Citation Nr: 1322995 Decision Date: 07/18/13 Archive Date: 07/24/13 DOCKET NO. 06-04 300 ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in New York, New York THE ISSUES 1. Entitlement to service connection for residuals of colorectal cancer, to include on a direct basis or as due to Agent Orange or asbestos exposure. 2. Entitlement to service connection for a gastrointestinal disorder (other than the residuals of colorectal cancer), to include diverticulitis and gastroesophageal reflux disease (GERD) on a direct basis or as due to Agent Orange or asbestos exposure. REPRESENTATION Appellant represented by: Vietnam Veterans of America ATTORNEY FOR THE BOARD L. M. Barnard, Senior Counsel INTRODUCTION The Veteran had active service from September 1967 to September 1970. This appeal arose before the Board of Veterans' Appeals (Board) from a January 2005 rating decision of the New York, New York Department of Veterans Affairs (VA), Regional Office (RO) that denied, in pertinent part, service connection for a stomach disorder, to include as due to Agent Orange exposure. A September 2005 RO decision (issued in a statement of the case (SOC)) denied, in pertinent part, service connection for residuals of colorectal cancer (claimed as a stomach disorder), to include as due to either Agent Orange or asbestos exposure. In October 2008, the Board remanded the issue of entitlement to service connection for the residuals of colorectal cancer (claimed as a stomach condition), to include as due to Agent Orange or asbestos exposure. In October 2009, the Board requested a Veteran's Health Administration (VHA) opinion and the VHA opinion was obtained in December 2009. The Board, in January 2010, then requested clarification of, and an addendum to, the December 2009 VHA opinion. This addendum was provided in February 2010. The Veteran and his representative were provided copies of the VAH opinion and its addendum in March 2010. The Veteran and his representative then submitted additional argument in April 2010. The Board, in April 2010, denied entitlement to service connection for the residuals of colorectal cancer (claimed as a stomach disorder), to include as due to Agent Orange or asbestos exposure. The Veteran subsequently appealed this decision to the Court of Appeals for Veterans Claims (CAVC). In October 2010, the parties (the Veteran and the VA Secretary) filed a Joint Motion for Remand (JMR) that requested that the Board's decision be vacated and remanded. This motion was granted by CAVC in an October 2010 Order. Following the return of the case to the Board, it was remanded in January 2011 for further evidentiary development. In August 2012, the Board again remanded this case for further development. At that time, it was noted that the Veteran had been pursuing a claim for service connection for the residuals of colorectal cancer, claimed as due to either asbestos or Agent Orange exposure. The Veteran had also appeared to claim that the "stomach problems" he had in service demonstrated the onset of a gastrointestinal disorder. The record also indicates the concurrent presence of other gastrointestinal disorders, diagnosed as diverticulitis and GERD. This remand noted that in Clemons v. Shinseki, 23 Vet. App. 1 (2009), CAVC had held that the scope of a claim must be understood from the viewpoint of a lay claimant who may not be required to understand sophisticated legal or medical distinctions, and that "the claimant's intent in filing a claim is paramount to construing its breadth." CAVC, citing Ingram v. Nicholson, 21 Vet. App. 232, 254 (2007), which held that VA must apply a "sympathetic reading" to a lay person's pleadings, indicated that VA's attention should be focused upon the symptoms the claim is attempting to service connect. In reviewing the record, it appears that the Veteran has been diagnosed with colorectal cancer, diverticulitis, and GERD. Given the holdings of Clemons and Boggs v. Peake, 520 F.3d 1330, 1337 (Fed. Cir. 2008), which found that separate diagnoses may constitute separate claims for adjudication purposes, the Board has rephrased the issues as noted in the title page. FINDINGS OF FACT 1. The Veteran's residuals of colorectal cancer are not related to any event of service, to include exposure to Agent Orange or asbestos. 2. The Veteran's diverticulitis is not related to any event of service, to include exposure to Agent Orange or asbestos. 3. The Veteran's GERD is not related to any event of service, to include exposure to Agent Orange or asbestos. CONCLUSIONS OF LAW 1. The residuals of colorectal cancer were not incurred in or aggravated by service, nor may they be presumed to have been so incurred. 38 U.S.C.A. §§ 1110, 1111, 5102, 5103, 5103A, 5107 (West 2002 & Supp. 2012); 38 C.F.R. §§ 3.159, 3.303, 3.304, 3.307, 3.309(e) (2012). 2. Diverticulitis was not incurred in or aggravated by service, nor may it be presumed to have been so incurred. 38 U.S.C.A. §§ 1110, 1111, 5102, 5103, 5103A, 5107 (West 2002 & Supp. 2012); 38 C.F.R. §§ 3.159, 3.303, 3.304, 3.307, 3.309(e) (2012). 3. GERD was not incurred in or aggravated by service, nor may it be presumed to have been so incurred. 38 U.S.C.A. §§ 1110, 1111, 5102, 5103, 5103A, 5107 (West 2002 & Supp. 2012); 38 C.F.R. §§ 3.159, 3.303, 3.304, 3.307, 3.309(e) (2012). REASONS AND BASES FOR FINDINGS AND CONCLUSIONS Stegall considerations A remand by the Board confers on an appellant the right to VA compliance with the terms of the remand order and imposes on the Secretary a concomitant duty to ensure compliance with those terms. See Stegall v. West, 11 Vet. App. 268, 271 (1998). In Stegall the Court held that "where . . . the remand orders of the Board . . . are not complied with, the Board itself errs in failing to insure compliance." Id. This case was remanded by the Board in January 2011. The RO was to contact the National Personnel Records Center (NPRC) in order to search for records pertaining to the Veteran's alleged 1968 hospitalization for stomach problems in Cam Ranh Bay. The NPRC responded in September 2011 that no records could be located. The Veteran was asked if he had these records and, if so, to provide them to VA; he failed to respond. In December 2011, the RO prepared a formal Memorandum of Unavailability. The January 2011 remand also requested private treatments records pertaining to treatment of the Veteran's colorectal cancer; these were received and associated with the claims folder. Finally, the RO was instructed to conduct a VA examination, which was performed in March 2011. Therefore, the instructions of the January 2011 remand have been complied with. The Board remanded all three issues in August 2012. The remand instructed that another VA examination be conducted in order to respond to a list of specific questions about the Veteran's claimed disorders. This examination was conducted in September 2012. A review of the examination report indicates that the questions asked in the remand were answered. Therefore, there was been substantial compliance with the August 2012 remand order. Because the prior remands have been complied with, no further remand is necessary to ensure compliance. VCAA The VCAA describes VA's duties to notify and assist claimants in substantiating a claim for VA benefits. 38 U.S.C.A. §§ 5100, 5102, 5103, 5103A, 5107, 5126; 38 C.F.R. §§ 3.102, 3.156(a), 3.159 and 3.326(a). The notice requirements were met in this case by development letters sent to the Veteran in November 2004, February 2005, March 2006, April 2011, and August 2012. This correspondence advised the Veteran of the information necessary to substantiate his claims and of his and VA's respective obligations for obtaining specified types of evidence. See Quartuccio v. Principi, 16 Vet. App. 183 (2002); 38 C.F.R. § 3.159(b). It also advised the Veteran of how disability ratings and effective dates are determined. See Dingess/Hartman v. Nicholson, 19 Vet. App. 473 (2006). The Veteran has not alleged that VA failed to comply with the notice requirements of the VCAA, and he was afforded a meaningful opportunity to participate effectively in the processing of his claim, and has in fact provided additional arguments at every stage. See Mayfield v. Nicholson, 19 Vet. App. 103 (2005). The notice required by 38 U.S.C.A. § 5103(a) should be provided to a claimant before the initial unfavorable agency of original jurisdiction (AOJ) decision on a claim. Pelegrini v. Principi, 18 Vet. App. 112 (2004); see also Mayfield v. Nicholson, 19 Vet. App. 103 (2005). That was done in this case. The Board also concludes VA's duty to assist has been satisfied. The Veteran's service treatment records and VA treatment records are in the file. The VA has also obtained private treatment records and associated them with the claims file. As such, the Board finds the duty to assist with obtaining medical records has been satisfied. The duty to assist also includes providing a medical examination or obtaining a medical opinion when such is necessary to make a decision on the claim, as defined by law. The case of McLendon v. Nicholson, 20 Vet. App. 79 (2006), held that an examination is required when (1) there is evidence of a current disability, (2) evidence establishing an "in-service event, injury or disease," or a disease manifested in accordance with presumptive service connection regulations occurred which would support incurrence or aggravation, (3) an indication that the current disability may be related to the in-service event, and (4) insufficient evidence to decide the case. The Board notes that the Veteran was afforded VA examinations in January 2009, March 2011, and September 2012. See 38 C.F.R. § 3.159(c)(4). A VHA opinion was obtained in December 2009, with a clarification provided February 2010. These opinions were rendered by medical professionals following a thorough examination and interview of the appellant and review of the claims file. These examiners obtained an accurate history and listened to the appellant's assertions. The examiners laid a factual foundation and reasoned basis for the conclusions that were reached. Therefore, the Board finds that the examinations are adequate. Barr v. Nicholson, 21 Vet. App. 303, 311 (2007). In light of the foregoing, the Board is satisfied that all relevant facts have been adequately developed to the extent possible; no further assistance to the appellant in developing the facts pertinent to the issue on appeal is required to comply with the duty to assist. 38 U.S.C.A. §§ 5103 and 5103A; 38 C.F.R. § 3.159. Applicable laws and regulations Competent medical evidence means evidence provided by a person who is qualified through education, training, or experience to offer medical diagnoses, statements, or opinions. Competent medical evidence may also mean statements conveying sound medical principles found in medical treatises. It would also include statements contained in authoritative writings such as medical and scientific articles and research reports or analyses. 38 C.F.R. § 3.159(a)(1) (2012). Competent lay evidence means any evidence not requiring that the proponent have specialized education, training, or experience. Lay evidence is competent if it is provided by a person who has knowledge of facts or circumstances and conveys matters that can be observed and described by a lay person. 38 C.F.R. § 3.159(a)(2) (2012). Service connection may be established for disability resulting from personal injury suffered or disease contracted in line of duty in the active military, naval, or air service. 38 U.S.C.A. § 1110. That an injury or disease occurred in service is not enough; there must be chronic disability resulting from that injury or disease. If there is no showing of a resulting chronic condition during service, then a showing of continuity of symptomatology after service is required to support a finding of chronicity. 38 C.F.R. § 3.303(b). Service connection may also be granted for any injury or disease diagnosed after discharge, when all the evidence, including that pertinent to service, establishes that the disease or injury was incurred in service. 38 C.F.R. § 3.303(d). In order to establish service connection for the claimed disorder on a direct basis, generally there must be probative evidence of (1) a current disability; (2) in-service incurrence or aggravation of a disease or injury; and (3) a nexus between the claimed in-service disease or injury and the current disability. See Hickson v. West, 12 Vet. App. 247, 253 (1999). A veteran who, during active military service, served in Vietnam during the period beginning in January 1962 and ending in May 1975, is presumed to have been exposed to herbicides. 38 C.F.R. §§ 3.307, 3.309 (2012). The last date on which such a veteran shall be presumed to have been exposed to an herbicide agent shall be the last date on which he or she served in the Republic of Vietnam during the Vietnam era. "Service in the Republic of Vietnam" includes service in the waters offshore and service in other locations if the conditions of service involved duty or visitation in the Republic of Vietnam. 38 C.F.R. § 3.307 (2012). For the purposes of this section, the term "herbicide agent" means a chemical in an herbicide used in support of the United States and allied military operations in the Republic of Vietnam during the Vietnam era. The diseases listed at 38 C.F.R. § 3.309(e) shall have become manifest to a degree of 10 percent or more at any time after service, except that chloracne or other acneform disease consistent with chloracne, porphyria cutanea tarda, and acute and subacute peripheral neuropathy shall have become manifest to a degree of 10 percent or more within a year, after the last date on which the veteran was exposed to an herbicide agent during active military, naval, or air service. If a veteran was exposed to an herbicide agent during active military, naval, or air service, the following diseases shall be service-connected even though there is no record of such disease during service: chloracne or other acneform disease consistent with chloracne, Type 2 diabetes, Hodgkin's disease, multiple myeloma, non-Hodgkin's lymphoma, acute and subacute peripheral neuropathy, porphyria cutanea tarda, prostate cancer, respiratory cancers (cancer of the lung, bronchus, larynx or trachea), and soft-tissue sarcoma (other than osteosarcoma, chondrosarcoma, Kaposi's sarcoma, or mesothelioma). 38 C.F.R. § 3.309(e). On August 31, 2010, the Secretary published a final rule in the Federal Register amending 38 C.F.R. § 3.309(e). See 75 Fed. Reg. 53.202. The final rule was effective August 31, 2010. Specifically, VA amended 38 C.F.R. § 3.309(e) to add hairy cell leukemia and other chronic B-cell leukemias, Parkinson's disease, and ischemic heart disease (including, but not limited to, acute, subacute, and old myocardial infarction; atherosclerotic cardiovascular disease including coronary artery disease (including coronary spasm) and coronary bypass surgery; and stable, unstable and Prinzmetal's angina) to the list of diseases associated with exposure to certain herbicide agents. A newly added Note 3 at the end of § 3.309 states that: "for purposes of this section, the term ischemic heart disease does not include hypertension or peripheral manifestations of arteriosclerosis such as peripheral vascular disease or stroke, or any other condition that does not qualify within the generally accepted medical definition of Ischemic heart disease." The availability of presumptive service connection for a disability based on exposure to herbicides does not preclude a veteran from establishing service connection with proof of direct causation. Stefl v. Nicholson, 21 Vet. App. 120 (2007); see also Combee v. Brown, 34 F.3d 1039 (Fed. Cir. 1994). The Secretary of VA, however, has reiterated on several occasions that there is no positive association between exposure to herbicides and any other condition for which it has not specifically determined that a presumption of service connection is warranted. See, e.g., 72 Fed. Reg. 32,395 (Jun. 12, 2007). There is no specific statutory or regulatory guidance with regard to claims for service connection for asbestosis or other asbestos-related diseases. However, in 1988, VA issued a circular on asbestos-related diseases that provided guidelines for considering asbestos compensation claims. See Department of Veterans Benefits, Veterans' Administration, DVB Circular 21-88-8, Asbestos-Related Diseases (May 11, 1988). The information and instructions contained in the DVB Circular have since been included in VA Adjudication Procedure Manual, M21-1MR, Part IV, Subpart ii, Chapter 2, Section C (hereinafter "M21-1MR"). Also, an opinion by VA's Office of General Counsel discusses the development of asbestos claims. VAOPGCPREC 4-00. VA must analyze the veteran's claim of entitlement to service connection for asbestosis under these administrative protocols using the following criteria. Ennis v. Brown, 4 Vet. App. 523, 527 (1993); McGinty v. Brown, 4 Vet. App. 428, 432 (1993). The M21-1MR contains guidelines for the development of asbestos exposure cases. Paragraph (a) lists common materials that may contain asbestos including steam pipes for heating units and boilers, ceiling tiles, roofing shingles, wallboard, fire-proofing materials, and thermal insulation. Paragraph (b) in essence acknowledges that inhalation of asbestos fibers can result in fibrosis, the most commonly occurring of which is interstitial pulmonary fibrosis or asbestosis. Inhaling asbestos fibers can also lead to pleural effusions and fibrosis, pleural plaques, mesotheliomas of the pleura and peritoneum, and cancer of the lung, bronchus, gastrointestinal tract, larynx, pharynx, and urogenital system (except the prostate). Paragraph (c) notes as important that all persons with significant asbestosis develop cor pulmonale, heart disease secondary to disease of the lung or its blood vessels, and those who do not die from cancer often die from heart failure secondary to cor pulmonale. Also of significance is that disease-causing exposure to asbestos may be brief, and/or indirect. Paragraph (d) states that the latency period for development of disease due to exposure to asbestos ranges from 10 to 45 or more years between the first exposure and the development of the disease. Paragraph (e) provides that a clinical diagnosis of asbestosis requires a history of exposure and radiographic evidence of parenchymal lung disease. Symptoms and signs include dyspnea on exertion, end-respiratory rales over the lower lobes, compensatory emphysema, clubbing of the fingers at late stages, and pulmonary function impairment and cor pulmonale that can be demonstrated by instrumental methods. Paragraph (f) indicates that some of the major occupations involving exposure to asbestos include mining; milling; work in shipyards; insulation work; demolition of old buildings; carpentry and construction; manufacture and servicing of friction products, such as clutch facings and brake linings; and manufacture and installation of products, such as roofing and flooring materials, asbestos cement sheet and pipe products, and military equipment. Paragraph (g) notes that high exposure to asbestos and high prevalence of disease have been noted in insulation and shipyard workers. During World War II, several million people employed in U.S. shipyards and U.S. Navy veterans were exposed to chrysotile products as well as amosite and crocidolite since these varieties were used extensively in military ship construction. Paragraph (h) provides that VA must determine whether service records demonstrate evidence of asbestos exposure during service; whether there is pre-service and/or post-service evidence of occupational or other asbestos exposure; and then make a determination as to the relationship between asbestos exposure and the claimed disease, keeping in mind the latency and exposure information pertinent to the veteran. In rendering a decision on appeal, the Board must analyze the credibility and probative value of the evidence, account for the evidence that it finds to be persuasive or unpersuasive, and provide the reasons for its rejection of any material evidence favorable to the claimant. See Gabrielson v. Brown, 7 Vet. App. 36, 39-40 (1994); Gilbert v. Derwinski, 1 Vet. App. 49, 57 (1990). Competency of evidence differs from weight and credibility. The former is a legal concept determining whether testimony may be heard and considered by the trier of fact, while the latter is a factual determination going to the probative value of the evidence to be made after the evidence has been admitted. See Rucker v. Brown, 10 Vet. App. 67, 74 (1997); Layno v. Brown, 6 Vet. App. 465, 469 (1994); see also Cartwright v. Derwinski, 2 Vet. App. 24, 25 (1991) ("Although interest may affect the credibility of testimony, it does not affect competency to testify."). Factual background and analysis The Veteran has stated his belief that his colorectal cancer, diverticulitis, and GERD are either directly related to his service, or were caused by in-service exposure to Agent Orange or asbestos. He served in Vietnam from April 28, 1968 to December 12, 1969; therefore, exposure to herbicides is presumed. See 38 C.F.R. § 3.307. During service, he worked as a vehicle mechanic, repairing and replacing various parts, to include brakes. As a consequence, the Board will concede that it is likely that he was exposed to asbestos in service. Colorectal cancer A review of the Veteran's service treatment records was negative for any complaints of, treatment for, or diagnosis of colorectal cancer. His July 1970 separation examination noted no stomach complaints and the objective examination was normal. The record indicates that the Veteran was diagnosed with, and surgically treated for, colorectal cancer in 2000. In June 2005, the Veteran's physician, C.W.R., provided a statement in which it was noted that the Veteran had been treated a few years before for colorectal cancer. This condition was considered to have been cured. The physician stated that "...common diseases associated with asbestosis include cancers of the gastrointestinal tract. I would like to make the statement that he has had colorectal cancer, and he has had exposure to asbestosis during his service connection, which could have been aggravated by this exposure." A VA examination performed in January 2009 referred to the Veteran's 2000 diagnosis and the surgical treatment (16 inches of bowel were resected). The examiner stated that there was no relationship between the Veteran's cancer and service, noting that there was no evidence of asbestosis in the record. C.W.R., the Veteran's physician, provided another statement in September 2009. He stated that "[t]he patient clearly has no other risk factor for having colon cancer....He had a colon resection and did very well and I believe that there is a 50% chance that the colon cancer was a result of his serving in the war." In November 2009, Dr. C.W.R. submitted another statement. He indicated that he had been the Veteran's family physician since 1999. He noted that the Veteran had no family history of colon cancer and that he had served in Vietnam. He had worked as a brakeman in Vietnam, where he routinely and on a daily basis worked on and fixed brake shoes/pads that contained asbestos. He was also exposed to Agent Orange in Vietnam. He opined that Clearly this would connect him to asbestosis and it has been shown by the military that asbestos fibers can cause cancer of the gastrointestinal tract. The patient has been diagnosed with colon cancer and I am 50% sure that this colon cancer was the result of him serving in the war and being exposed to asbestos when he worked on the brakes of military vehicles. The Board requested a VHA opinion that was provided in December 2009. A review of the Veteran's service treatment records noted a history of hepatitis with jaundice at the time of his entrance examination. However, an examination of the gastrointestinal system was normal, and this illness was considered to have resolved. Colon cancer was not diagnosed until 2000, 30 years after his separation from service. It was stated that "[t]here is no evidence this colorectal cancer and symptoms of alternating constipation and diarrhea are due to any aspect of his period of service including possible in-service exposure to Agent Orange or asbestos." It was further stated that "[t]he accuracy of Dr. R[ ] comments in 2005 and 2009 are questionable. There is no evidence of asbestosis or that an exposure to asbestos would have 'aggravated' his colorectal cancer or its response to surgical treatment." The Veteran's submitted an Internet article, obtained from the Environmental Protection Agency's website. This noted that airborne exposure could be from asbestos-related industries or from clutches and brakes on cars and trucks. Studies reported an increase in gastrointestinal cancer from the inhalation exposure and subsequent oral ingestion. Another VA examination was performed in March 2011. His medical history was noted, as well as the fact that his cancer had been in remission for 10 years. Exposure to Agent Orange was presumed by the examiner. The examiner referred to the National Academy's Institute of Medicine, which has yet to establish a relationship between exposure to Agent Orange and colon cancer. The medical literature was also equivocal as to any increased risk of colon cancer and exposure to asbestos. Some studies had shown an increased risk of 1.5 when compared to the unexposed population. The examiner said that in service the Veteran had replaced worn or broken parts of wheel and track vehicles. The examiner further commented that the Veteran had not repaired these parts but had only replaced them; he had not refurbished brakes or clutches, which might have caused significant risk of exposure. It was noted that there was an increased incidence of colon cancer in those who drank water contaminated with asbestos, but there was no evidence of such exposure in the Veteran's case. The examiner stated that given his work in the Department of Corrections for the past 32 years, there was no risk of post-service occupational exposure. Because the most common port of entry for asbestos is the lungs, an x-ray was taken to look for pathognomonic changes reflective of such exposure (such as pleural thickening, pleural masses, or pleural plaques); nothing was found. The examiner commented that the private physicians ....letter shed no on the potential association of colon cancer in relation to Agent Orange or asbestos exposure. In light of the previous discussion, it is the opinion of this evaluator that the Veteran's colon cancer was not as least as likely as not related to his presumed exposure to Agent Orange during military service or putative exposure to asbestos during military service. An article from the Agency for Toxic Substances and Disease Registry was submitted by the Veteran. This stated that it was considered prudent to consider an increased risk of gastrointestinal cancer as a possible effect of asbestos exposure. It was further stated that asbestos exposure might be associated with colon cancer, although the association was considered controversial. Private outpatient treatment records developed between 2005 and 2009 noted the Veteran's history of smoking less than one pack per day for 12 years; he quit in 1977. He drank alcohol (beer and whiskey sours) on the weekends. He was also noted to be 5 feet, 9 inches tall and weighed 224 pounds. In April 2012, the Veteran's physician, C.W.R. provided another statement. He stated that he disagreed with the March and December 2011 VA opinions. He stated that "[i]t is my medical opinion that it is at least as likely as not that [the Veteran's] colon cancer was the result of his exposure to asbestos in the military." He listed various medical treatises the he had reviewed and which were attached to his statement. He indicated that he had relied on his relationship with the Veteran and his 12 years of treatment of the Veteran. Based on the history provided by the Veteran, the physician stated that the Veteran had had both inhaled and oral exposure to asbestos. The reviewed studies indicated that auto mechanics, who used compressed air hoses to clean dust from brake parts, were exposed to asbestos. The physician referred to one of the VA examinations that had stated that the Veteran had only replaced parts and had not refurbished them, thus having a reduced risk of exposure. The examiner stated that this conclusion by the VA examiner was not supported by the evidence of record. He also commented that the VA examiners had not considered all the new articles on this topic, which noted that a relationship between colon cancer and asbestos was suggested. Dr. R. again stated that the Veteran had no family history of colon cancer and that he had had no exposure outside the military. VA re-examined the Veteran in September 2012. The Veteran's history of having reported severe left lower quadrant abdominal pain in 1968 was noted. He was treated for several days, and there had been no further recurrence since that time. His cancer was detected on a routine colonoscopy in 2000; he underwent a resection and there has been no recurrence. He complained of alternating diarrhea and constipation, but denied any weight loss. After reviewing the entire record, to include the Veteran's and his physician's statements, the prior examinations, and the various articles, the examiner found that the colon cancer had not had its onset in service. The acute episode of abdominal pain in service in Vietnam was not related to a diagnosis of colon cancer made some 33 years later. It was pointed out that, if the Veteran had had colon cancer in service, he would not have been symptoms-free for some 33 years. The examiner also found it not at least as likely as not that the colon cancer was caused or aggravated by asbestos exposure. The Institute of Medicine of the National Academy had reviewed 120 studies concerning a relationship between asbestos and cancers of the digestive tract. While the evidence was suggestive, there was insufficient evidence to infer a causal link. The World Health Organization's Agency for Research on Cancer Working Group (which had been referred to by the Veteran's private physician) suggested but could not confirm a causal link. The authors had stated that a major limitation of the study was the absence of individual data on co-founding factors such as tobacco and alcohol use and diet, all of which are known risk factors in the development of colon cancer. In the instant case, the Veteran was noted to have smoked until 1977 (1 to 2 packs per day); he has used alcohol regularly; and he is overweight. All of these are risk factors for the development of colon cancer. After a careful review of the evidence of record it is found that entitlement to service connection for colon cancer and its residuals is not warranted. There is no indication in the service treatment records that this disorder was present in service. There were no complaints of, treatment for, or diagnosis of colon cancer in service. After a thorough review of the record, it was determined that the colon cancer, diagnosed in 2000, was not related to one acute episode of abdominal pain in service, particularly since this complaint was never noted again in service, his separation examination was normal, and the record was silent for treatment for over 30 years. The Board notes that the passage of time can be taken into consideration in determining whether a disorder developed as a result of an injury sustained in service. See Maxson v. Gober, 230 F.3d 1330, 1333 (Fed. Cir. 2000) (noting that it was proper to consider the veteran's entire medical history, including the length period of absence of complaint with respect to the condition now raised). Therefore, there is no evidence to support a finding of direct service connection. The Veteran has also alleged that his colon cancer was caused or aggravated by exposure to either Agent Orange or asbestos. There is no question that the Veteran was exposed to Agent Orange during his period of service in Vietnam. See 38 C.F.R. § 3.307. It is also likely, given the Veteran's military occupational specialty, that he was exposed to asbestos. However, colon cancer is not listed as one of the diseases that may be presumed to be related to Agent Orange exposure. See 38 C.F.R. § 3.309(e). However, he may still establish that Agent Orange was the cause of this condition, pursuant to Combee, supra. Unfortunately, after reviewing all of the evidence, it cannot be found that the Veteran's colon cancer is related to his conceded exposure to Agent Orange. The Board has considered all of the opinions provided, to include those from the Veteran's private physician and the VA examiners, as well as the VHA opinion. None of these opinions supports a finding that Agent Orange was the direct cause of his colon cancer, diagnosed some 30 after his discharge from service. The Veteran has also alleged that his in-service exposure to asbestos resulted in the development of colon cancer. His private physician, relying on several articles on the subject, concluded that the asbestos exposure the Veteran suffered, both oral and inhaled, caused him to develop colon cancer. This physician also repeatedly stated that the Veteran had no other risk factors for the development of this disease and that, therefore, the only remaining cause was his asbestos exposure during service. VA obtained examinations in January 2009, March 2011, and September 2012, and a VHA opinion in December 2009. In contrast to the private opinions, these examiners, after reviewing the same studies referred to by the private physician, noted that they were merely suggestive of a link between asbestos exposure and colon cancer. However, despite this suggestion, these studies were unable to confirm a causal link. Moreover, it was pointed out that these studies did not deal with individual data, nor did they consider other contributing factors to the development of colon cancer (smoking history, weight, and alcohol use). After taking all of this into consideration, these examiners all concluded that asbestos exposure had not caused the Veteran's colon cancer. After weighing these various opinions, the Board affords greater probative weight to the opinions provided by the VA examiners. This is particularly true since it does not appear that the private physician considered all the factors that could result in the development of colon cancer. For example, the private physician had unequivocally stated that the Veteran had no risk factors for the development of colon cancer other than his exposure to asbestos. However, the record clearly indicates that the Veteran had a 12-year history of smoking, having quit in 1977; was a regular user of alcohol; and was overweight, all of which are risk factors in the development of colon cancer. The private physician had also referred to various articles that suggested a link between colon cancer and asbestos, particularly the oral ingestion of asbestos. However, upon review of these articles, it is clear that they do not provide evidence of a confirmed causal link. A suggestion of a link is far too speculative in nature and does not provide sufficient evidence of service connection. Moreover, the private physician had stressed that the Veteran had orally ingested asbestos. The objective evidence does not support a finding of such exposure; there is no indication that he had ever ingested contaminated water. Therefore, the Board finds that the VA examiners who, after thorough examinations, had considered the Veteran's various risk factors and had clearly noted the equivocal and speculative nature of the articles, should be afforded great probative weight. See Prejean v. West, 13 Vet. App. 444, 448-9 (2000) (holding that among the factors for assessing the probative value are the physician's access to the claims file and the thoroughness and detail of the opinion). The Board also notes that the private physician had based his opinions on the fact that he was familiar with the Veteran, having been his treating physician since 1999. The Board acknowledges that it is neither free to ignore the opinion of a treating physician nor required to accord it additional or dispositive weight. CAVC has declined to adopt a "treating physician rule" under which a treating physician's opinion would presumptively be given greater weight than that of a VA examiner or another doctor. See Winsett v. West, 11 Vet. App. 420, 424-25 (1998); Guerrieri v. Brown, 4 Vet. App. 467, 471-73 (1993). The United States Court of Appeals for the Federal Circuit (Federal Circuit) also has declined to adopt a "treating physician rule," which would give preference, i.e., additional evidentiary weight, to this type of evidence. See White v. Principi, 243 F 3d. 1378 (Fed. Cir. 2001). As a consequence, as noted above, the Board has accorded the greatest probative weight to the various VA examinations and the VHA opinion, particularly when considered in the totality of all the evidence of record. The Board has read and considered the medical treatises and articles provided by the Veteran that are "suggestive" of a link between his colon cancer and his acknowledged exposure to asbestos. The Board notes that medical treatise evidence can, in some circumstances, constitute competent medical evidence. See Wallin v. West, 11 Vet. App. 509, 514 (1998); see also 38 C.F.R. § 3.159(a)(1) (competent medical evidence may include statements contained in authoritative writings such as medical and scientific articles and research reports and analyses). Similarly, medical treatise evidence could "discuss generic relationships with a degree of certainty such that, under the facts of a specific case, there is at least a plausible causality based upon objective facts." Mattern v. West, 12 Vet. App. 222, 229 (1999); Sacks v. West, 11 Vet. App. 314, 317 (1998), Libertine v. Brown, 9 Vet. App. 521 (1996); Beausoleil v. Brown, 8 Vet. App. 459 (1996). However, the articles submitted by the Veteran and his representative are of a general nature and do not contain any information or analysis specific to the Veteran's case. As such, the evidence submitted by the Veteran is not persuasive as to the etiology of his colon cancer. CAVC has held on several occasions that medical evidence that is speculative, general or inconclusive in nature cannot support a claim. See generally Obert v. Brown, 5 Vet. App. 30, 33 (1993); Tirpak v. Derwinski, 2 Vet. App. 609, 611 (1992). The Board acknowledges that competent medical evidence is not necessarily required where the determinative issue in a case involves medical causation or a medical diagnosis. Davidson v. Shinseki, 581 F.3d 1313, 1316 (Fed. Cir. Sept. 14, 2009), citing Jandreau v. Nicholson, 492 F.3d 1372, 1376-77 (Fed. Cir. 2007); see also Barr v. Nicholson, 21 Vet App 303 (2007) (lay testimony is competent to establish the presence of varicose veins); Woehlaert v. Nicholson, 21 Vet. App. 456, 462 (2007) (unlike varicose veins or a dislocated shoulder, rheumatic fever is not a condition capable of lay diagnosis). However, unlike the varicose veins in Barr or dislocated shoulder in Jandreau, colon cancer is not a condition that can be causally related to asbestos or Agent Orange exposure without medical expertise. Davidson, 581 F.3d 1313; Buchanan, 451 F.3d 1331; Jandreau, 492 F.3d 1372. Thus, the Board concludes that, although the Veteran is competent to report symptoms, his statements as to the cause of his colon cancer do not constitute competent evidence. Although lay persons are competent to provide opinion on some medical issues, see Kahana v. Shinseki, 24 Vet. App. 428, 435 (2011), as to the specific issue in this case, whether colon cancer is related to Agent Orange or asbestos exposure, falls outside the realm of common knowledge of a lay person. In light of the above, the Board finds that the preponderance of the evidence is against the Veteran's claim for service connection for colon cancer. Because the preponderance of the evidence is against the Veteran's claim, the benefit of the doubt provision does not apply. Accordingly, the Board concludes that service connection for colon cancer is not warranted. See 38 U.S.C.A. § 5107(b) (West 2002); 38 C.F.R. §§ 3.102, 3.303, 3.304 (2012). Diverticulitis The Veteran's service treatment records include his June 1967 entrance examination, which made no reference to diverticulitis. His July 1970 separation examination was also within normal limits, with no gastrointestinal complaints noted. While he reported one episode in 1968 of acute left lower quadrant abdominal pain, there is no suggestion that diverticulitis was diagnosed. There were no other complaints in service. Following service, there were notations in private treatment records developed between 2005 and 2009 of a history of diverticulitis. A VHA opinion obtained in December 2009 noted a history of colonic diverticulosis. In February 2010, a clarification of the VHA opinion was provided to the Board. The examiner stated that the Veteran's history of diverticulitis would not be as likely as not related to any aspect of his period of service, to include possible in-service exposure to Agent Orange or asbestos. Diverticulitis was noted to be a common medical disorder that appears in the normal adult population and was not related to or aggravated by any aspect of his service. There is no opinion of record that contradicts this VHA opinion. After a careful review of the evidence, the Board finds that entitlement to service connection for diverticulitis has not been established. Significantly, this disorder has been noted by history only; there is no current diagnosis of diverticulitis. Because entitlement to service connection requires the presence of a current disability, the Board finds that service connection for this disorder has not been established. See Brammer v. Derwinski, 3 Vet. App. 223 (1992) (indicating that service connection presupposes a current diagnosis of the condition claimed). GERD A review of the Veteran's service treatment records do not show any complaints of, treatment for, or diagnosis of, GERD. His June 1967 entrance and his July 1970 separation examinations make no reference to this disorder. Private outpatient treatment records show treatment for GERD. In December 2008, he was under medical care for reflux disease. A VHA opinion obtained by the Board in December 2009 referred to the Veteran's diagnosis of GERD. A clarification obtained in February 2010 stated that his GERD was not related to any aspect of his service, to include possible exposure to asbestos or Agent Orange. This was noted to be an extremely common disease in the normal adult population, which was not caused or aggravated by any aspect of his service. Clearly, the Veteran suffers from GERD; therefore, a current disability is present. However, there is no indication that this disorder was present in service; in fact, it was not noted in his treatment records until after 2000, over 30 years after service. Since there is no evidence that this condition was present in service, direct service connection cannot be granted. The Board has also considered whether the Veteran's GERD could be related to his acknowledged in-service exposure to Agent Orange or asbestos. This condition is not listed as one of those disease that may be presumed to be related to Agent Orange under 38 C.F.R. § 3.309(e); however, direct service connection could be awarded pursuant to Combee, supra. A review of the evidence of record does not support a finding that the Veteran's diagnosed GERD is related to either Agent Orange or asbestos. The VHA opinion provided in February 2010 ruled out such a causal connection and there is no evidence of record to contradict this opinion. Therefore, service connection on this basis cannot be awarded. The Board acknowledges that competent medical evidence is not necessarily required where the determinative issue in a case involves medical causation or a medical diagnosis. Davidson v. Shinseki, 581 F.3d 1313, 1316 (Fed. Cir. Sept. 14, 2009), citing Jandreau v. Nicholson, 492 F.3d 1372, 1376-77 (Fed. Cir. 2007); see also Barr v. Nicholson, 21 Vet App 303 (2007) (lay testimony is competent to establish the presence of varicose veins); Woehlaert v. Nicholson, 21 Vet. App. 456, 462 (2007) (unlike varicose veins or a dislocated shoulder, rheumatic fever is not a condition capable of lay diagnosis). However, unlike the varicose veins in Barr or dislocated shoulder in Jandreau, GERD is not a condition that can be causally related to asbestos or Agent Orange exposure without medical expertise. Davidson, 581 F.3d 1313; Buchanan, 451 F.3d 1331; Jandreau, 492 F.3d 1372. Thus, the Board concludes that, although the Veteran is competent to report symptoms, his statements as to the cause of his GERD do not constitute competent evidence. Although lay persons are competent to provide opinion on some medical issues, see Kahana v. Shinseki, 24 Vet. App. 428, 435 (2011), as to the specific issue in this case, whether GERD is related to Agent Orange or asbestos exposure, falls outside the realm of common knowledge of a lay person. In light of the above, the Board finds that the preponderance of the evidence is against the Veteran's claim for service connection for GERD. Because the preponderance of the evidence is against the Veteran's claim, the benefit of the doubt provision does not apply. Accordingly, the Board concludes that service connection for GERD is not warranted. See 38 U.S.C.A. § 5107(b) (West 2002); 38 C.F.R. §§ 3.102, 3.303, 3.304 (2012). ORDER Entitlement to service connection for the residuals of colorectal cancer is denied. Entitlement to service connection for diverticulitis is denied. Entitlement to service connection for GERD is denied. ____________________________________________ DENNIS F. CHIAPPETTA Veterans Law Judge, Board of Veterans' Appeals Department of Veterans Affairs