Citation Nr: 1455083 Decision Date: 12/15/14 Archive Date: 12/24/14 DOCKET NO. 09-13 233 ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in St. Petersburg, Florida THE ISSUE Entitlement to service connection for the cause of the Veteran's death. REPRESENTATION Appellant represented by: The American Legion WITNESS AT HEARING ON APPEAL Appellant ATTORNEY FOR THE BOARD R. Williams, Counsel INTRODUCTION The appellant is the surviving spouse of a Veteran who served on active duty from October 1967 to December 1971. He died in January 2005. This appeal comes before the Board of Veterans' Appeals (Board) on appeal from a May 2008 rating decision by the St. Petersburg, Florida, Department of Veterans Affairs (VA) Regional Office (RO). In November 2010, a Travel Board hearing was held before a Veterans Law Judge who is no longer at the Board. A transcript of the hearing is associated with the claims file. In July 2012, the appellant was asked if she wanted to have another hearing. She responded by indicating that she did not want to appear at a hearing and to consider the case on the evidence of record; therefore, the Board will proceed. The Board previously remanded this matter for additional development in February 2011. The Appeals Management Center (AMC) made reasonable efforts to comply with the Board's remand directive and the claim was readjudicated in an October 2014 supplemental statement of the case. For this reason, the Board concludes that that the Board's remand orders have been substantially complied with, and it may proceed with a decision at this time. See Dyment v. West, 13 Vet. App. 141, 146-47 (1999) (remand not required under Stegall v. West, 11 Vet. App. 268 (1998), where the Board's remand instructions were substantially complied with), aff'd, Dyment v. Principi, 287 F.3d 1377 (Fed. Cir. 2002). FINDINGS OF FACT 1. The Veteran died in January 2005; a death certification lists esophageal cancer as the cause of death. 2. At the time of the Veteran's death, he was not service connected for any disabilities. 3. The Veteran is presumed to have been exposed to Agent Orange due to his service in Vietnam; there is no esophageal injury or disease in service. 4. Symptoms of esophageal cancer were not chronic in service. 5. Symptoms of esophageal cancer have not been continuous since service separation. 6. The esophageal cancer that caused the Veteran's death is not related to active service and is not related to any diagnoses presumptively related to Agent Orange. CONCLUSIONS OF LAW 1. Esophageal cancer was not incurred in service and is not presumed to have been so incurred. 38 U.S.C.A. §§ 1101, 1110, 1112, 1113, 1116, 1312, 5103, 5103A, 5107, 7104 (West 2002); 38 C.F.R. §§ 3.102, 3.159, 3.303, 3.307, 3.309, 3.310, 3.312 (2014). 2. The criteria for service connection for the cause of the Veteran's death have not been met. 38 U.S.C.A. §§ 1310, 5103, 5103A, 5107 (West 2002); 38 C.F.R. §§ 3.102, 3.159, 3.312 (2014). REASONS AND BASES FOR FINDINGS AND CONCLUSIONS Remand Compliance As noted above, this appeal involved a remand by the Board for additional evidentiary development. A remand by the Board confers on the claimant, as a matter of law, the right to compliance with the remand orders. Stegall v. West, 11 Vet. App. 268, 271 (1998). While substantial compliance is required, strict compliance is not. D'Aries v. Peake, 22 Vet. App. 97, 105 (2008) citing Dyment v. West, 13 Vet. App. 141, 146-47 (1999). In this case, the RO substantially complied with the Board's remand instructions by ensuring that all notification required by the VCAA is completed. A letter was sent to the appellant in February 2011 which included a statement that the Veteran was not service connected for any disabilities, and an explanation of the evidence and information required to substantiate a DIC claim based on disability not yet service connected. The RO did not address the element of effective date as required by Dingess; however, the notice defect is harmless error because the claim is being denied for reasons explained below, and no effective date will be assigned. In addition, the RO obtained an opinion (February 2012 ) and addendum (April 2012) regarding whether the Veteran's diabetes mellitus, hypertension, diabetic retinopathy, coronary artery disease, and prior myocardial infarction, considered to be related to Agent Orange exposure, at least as likely as not caused or aggravated the Veteran's esophageal cancer. The supporting rationale was provided. The addendum opinion reflects that the claims file was reviewed. As there is substantial compliance with the Board's remand instructions, a remand is not necessary. Duties to Notify and Assist The Veterans Claims Assistance Act of 2000 (VCAA) enhanced VA's duty to notify and assist claimants in substantiating their claims for VA benefits. 38 U.S.C.A. §§ 5100, 5102, 5103, 5103A, 5107, 5126 (West 2002); 38 C.F.R. §§ 3.102, 3.156(a), 3.159, 3.326(a) (2012). Upon receipt of a complete or substantially complete application for benefits, VA is required to notify the claimant and his representative of any information, and any medical or lay evidence, that is necessary to substantiate the claim. 38 U.S.C.A. § 5103(a); 38 C.F.R. § 3.159(b). Proper notice from VA must inform the claimant of any information and evidence not of record (1) that is necessary to substantiate the claim; (2) that VA will seek to provide; and (3) that the claimant is expected to provide. 38 C.F.R. § 3.159(b)(1). This notice must be provided prior to an initial unfavorable decision on a claim by the RO. Mayfield v. Nicholson, 444 F.3d 1328 (Fed. Cir. 2006); Pelegrini v. Principi, 18 Vet. App. 112 (2004). The United States Court of Appeals for Veterans Claims (Court) issued a decision in the appeal of Dingess v. Nicholson, 19 Vet. App. 473 (2006), which held that the notice requirements of 38 U.S.C.A. § 5103(a) and 38 C.F.R. § 3.159(b) apply to all five elements of a service-connection claim, including the degree of disability and the effective date of an award. Those five elements include: (1) veteran status; (2) existence of a disability; (3) a connection between a veteran's service and the disability; (4) degree of disability; and (5) effective date of the disability. In the context of a claim for Dependency and Indemnity Compensation (DIC) benefits, which includes a claim of service connection for the cause of a veteran's death, section 5103(a) notice must be tailored to the claim. The notice should include: (1) a statement of the conditions, if any, for which a veteran was service connected at the time of his or her death; (2) an explanation of the evidence and information required to substantiate a DIC claim based on a previously service-connected condition; and (3) an explanation of the evidence and information required to substantiate a DIC claim based on a condition not yet service connected. Unlike a claim to reopen, an original DIC claim imposes upon VA no obligation to inform a DIC claimant who submits a nondetailed application of the specific reasons why any claim made during the deceased veteran's lifetime was not granted. Where a claimant submits a detailed application for benefits, VA must provide a detailed response. Hupp v. Nicholson, 21 Vet. App. 342 (2007). If complete notice is not provided until after the initial adjudication, such a timing error can be cured by subsequent legally adequate VCAA notice, followed by readjudication of the claim, as in a statement of the case (SOC) or a supplemental SOC (SSOC). Moreover, where there is an uncured timing defect in the notice, subsequent action by the RO which provides the claimant a meaningful opportunity to participate in the processing of the claim can prevent any such defect from being prejudicial. Mayfield v. Nicholson, 499 F.3d 1317, 1323-24 (Fed. Cir. 2007); Prickett v. Nicholson, 20 Vet. App. 370, 376 (2006). In this case, VCAA notice was sent to the appellant in February 2011, which was after the initial denial of the claim. The February 2011 letter provided notice to the appellant regarding what information and evidence is needed to substantiate a claim for service connection based on the cause of a Veteran's death, as well as what information and evidence must be submitted by the appellant, and what evidence VA would obtain. The RO did not address the element of effective date as required by Dingess; however, the notice defect is harmless error because the claim is being denied for reasons explained below, and no effective date will be assigned. After issuance of the February 2011 notice letter, the RO readjudicated the claim; therefore, the defect regarding the timing of the notice was remedied. 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. 38 U.S.C.A. § 5103A; 38 C.F.R. § 3.159(c); McLendon v. Nicholson, 20 Vet. App. 79, 81-82 (2006). Regarding VA's duty to assist in claims development, the Federal Circuit has held that 38 U.S.C.A. § 5103A(a) applies to DIC claims. Wood v. Peake, 520 F.3d 1345, 1348 (Fed. Cir. 2008); DeLaRosa v. Peake, 515 F.3d 1319 (Fed. Cir. 2008). Under such statutory authority, VA is required to make reasonable efforts to assist a claimant in obtaining evidence necessary to substantiate his or her claim. 38 U.S.C.A. § 5103A (a)(1). According to the Federal Circuit, this requirement obligates VA to assess whether it is necessary to obtain a medical opinion in order to substantiate the appellant's claim. Wood, 520 F.3d at 1348. VA is only excused from making reasonable efforts to provide assistance, if requested, when "no reasonable possibility exists that such assistance would aid in substantiating the claim." 38 U.S.C. § 5103A(a)(2). However, VA is not required to provide assistance to a claimant if no reasonable possibility exists that such assistance would aid in substantiating the claim. The Board is satisfied VA has made reasonable efforts to obtain relevant records and evidence. Specifically, the information and evidence that has been associated with the claims file includes the Veteran's service treatment records, post-service VA and private treatment records, and the appellant's written assertions and hearing testimony regarding her claim. In addition, a VA opinion was obtained in February 2012, and an addendum opinion was obtained in April 2012. These opinions satisfy the duty to assist. Regarding the appellant's assertion that the Veteran's presumed exposure to herbicide agents during service caused or substantially contributed to his death, the Board notes that esophageal cancer is not enumerated as a disease associated with herbicide exposure under 38 U.S.C.A. § 3.159(e), and the appellant has not provided competent evidence of a relationship between the Veteran's esophageal cancer and presumed exposure to herbicide agents during service. As discussed below, the appellant offers only her own conclusory opinion regarding causation. The etiology of esophageal cancer is outside the realm of common lay knowledge. See Jandreau v. Nicholson, 492 F.3d 1372, 1377 , n.4 (Fed. Cir. 2007) (lay persons not competent to diagnose cancer); Rucker v. Brown, 10 Vet. App. 67, 74 (1997) (stating that a lay person is not competent to diagnose or make a competent nexus opinion about a disorder as complex as cancer). The appellant has not provided competent lay evidence derived from personal knowledge or what she has been told by a medical professional. This is insufficient to satisfy the criteria of 38 U.S.C.A. § 5103A(d)(2). See id. As there is no competent evidence of record demonstrating an indication that the current disability may be related to an in-service event, a medical examination or opinion is not warranted for the claimed esophageal cancer. See McLendon, 20 Vet. App. at 81-82. Also, the Veteran's service treatment records are absent of any complaints, findings, or treatment for esophageal problems, and the Veteran's esophageal cancer is shown to have first manifested many years after service. Neither the appellant nor the representative has made the RO or the Board aware of any other evidence relevant to the appeal that needs to be obtained. Based on the foregoing, the Board finds that all relevant facts have been properly and sufficiently developed in this appeal and no further development is required. In view of the foregoing, the Board will proceed with appellate review. Legal Criteria and Analysis It is the Board's responsibility to evaluate the entire record on appeal. See 38 U.S.C.A. § 7104(a) (West 2002). The Board has thoroughly reviewed all the evidence of record in this case. The analysis below focuses on the most relevant evidence and on what this evidence shows, or fails to show, on the claim. See Gonzales v. West, 218 F.3d 1378, 1380-81 (Fed. Cir. 2000) (the Board must review the entire record, but does not have to discuss each piece of evidence). When there is an approximate balance in the evidence regarding the merits of an issue material to the determination of the matter, the benefit of the doubt in resolving each such issue shall be given to the claimant. 38 U.S.C.A. § 5107(b) (West 2002); 38 C.F.R. § 3.102 (2014). Dependency and indemnity compensation (DIC) is payable to the surviving spouse of a veteran if the veteran died from a service-connected disability. 38 U.S.C.A. § 1310; 38 C.F.R. § 3.5 (2014). The death of a veteran will be considered as having been due to a service-connected disability when the evidence establishes that such disability was either the principal or a contributory cause of death. The issue involved will be determined by exercise of sound judgment, without recourse to speculation, after a careful analysis has been made of all the facts and circumstances surrounding the death of the veteran, including, particularly autopsy reports. 38 C.F.R. § 3.312(a). The service connected disability will be considered as the principal (primary) cause of death when such disability, singly or jointly with some other condition, was the immediate or underlying cause of death or was etiologically related thereto. 38 C.F.R. § 3.312(b). Contributory cause of death is inherently one not related to the principal cause. In determining whether the service-connected disability contributed to death, it must be shown that it contributed substantially or materially; that it combined to cause death; that it aided or lent assistance to the production of death. It is not sufficient to show that it casually shared in producing death, but rather it must be shown that there was a causal connection. 38 C.F.R. § 3.312(c)(1). In order to establish service connection for the cause of death, there must be (1) evidence of death; (2) evidence of in-service incurrence or aggravation of a disease or injury; and (3) medical evidence of a nexus between the claimed in-service disease or injury and death. Hickson v. West, 12 Vet. App. 247, 253 (1999). In rendering a decision on appeal the Board must analyze the credibility and probative value of the evidence, account for the evidence which it finds to be persuasive or unpersuasive, and provide the reasons for its rejection of any material evidence favorable to the claimant. 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. Competency is a legal concept determining whether testimony may be heard and considered by the trier of fact, while credibility is a factual determination going to the probative value of the evidence to be made after the evidence has been admitted. Rucker v. Brown, 10 Vet. App. 67, 74 (1997); Layno v. Brown, 6 Vet. App. 465, 469 (1994); see also Cartright v. Derwinski, 2 Vet. App. 24, 25 (1991) ("although interest may affect the credibility of testimony, it does not affect competency to testify"). Lay testimony is competent when it regards the readily observable features or symptoms of injury or illness and "may provide sufficient support for a claim of service connection." See Layno v. Brown, 6 Vet. App. 465, 469 (1994); 38 C.F.R. § 3.159(a)(2). Lay statements may serve to support a claim for service connection by supporting the occurrence of lay-observable events or the presence of disability or symptoms of disability subject to lay observation. See Jandreau v. Nicholson, 492 F.3d 1372 (Fed. Cir. 2007); Buchanan v. Nicholson, 451 F.3d 1331, 1336 (Fed. Cir. 2006) (addressing lay evidence as potentially competent to support presence of disability even where not corroborated by contemporaneous medical evidence). The Court has emphasized that when a condition may be diagnosed by its unique and readily identifiable features, the presence of the disorder is not a determination "medical in nature" and is capable of lay observation. In such cases, the Board is within its province to weigh that testimony and to make a credibility determination as to whether that evidence supports a finding of service incurrence and continuity of symptomatology sufficient to establish service connection. See Barr v. Nicholson, 21 Vet. App. 303 (2007); Davidson v. Shinseki, 581 F.3d 1313 (Fed. Cir. Sept. 14, 2009). In this case, the Veteran died of esophageal cancer in January 2005. The death certificate identifies no other causes or significant contributory conditions for the Veteran's death. At the time of the Veteran's death, service connection was not in effect for any disability. The appellant alleges that the Veteran's exposure to herbicide agents during active service caused esophageal cancer and, ultimately, the Veteran's death, or in the alternative that the Veteran's diabetes mellitus was a contributing factor in the Veteran's death. See hearing transcript at page 17. She asserts that the Veteran experienced gastrointestinal problems in service, and that he later developed esophageal cancer. She further asserts that the Veteran's diabetes mellitus contributed to the cause of the Veteran's death. In order to establish presumptive service connection for a disease associated with exposure to certain herbicide agents, the evidence must show the following: (1) that the Veteran served in the Republic of Vietnam during the period beginning on January 9, 1962 and ending on May 7, 1975; (2) that he suffered from a disease associated with exposure to certain herbicide agents enumerated under 38 C.F.R. § 3.309(e); and (3) that the disease process manifested to a degree of 10 percent or more within the specified time period prescribed in section 3.307(a)(6)(ii). 38 U.S.C.A. § 1116; 38 C.F.R. §§ 3.307(a)(6), 3.309(e). After reviewing the lay and medical evidence of record, the Board finds that the weight of the evidence is against finding that the Veteran's presumed exposure to herbicide agents caused or contributed substantially or materially to the development of esophageal cancer, the cause of his death. Initially, the Board notes that the Veteran has qualifying Vietnam service and is, therefore, presumed to have been exposed to herbicide agents during active service. Thus, exposure to herbicide agents during service is not in dispute in this case. Nonetheless, the Veteran is not shown to have died due to any disability subject to presumptive service connection based on herbicide exposure, to include diabetes mellitus or coronary artery disease. As stated above, the only cause of death identified on the death certificate is esophageal cancer. Esophageal cancer is not enumerated as a disease associated with herbicide exposure under 38 U.S.C.A. § 3.309(e), and the record does not reflect competent medical evidence of a relationship between the later developed esophageal cancer and the presumed herbicide exposure during service. Therefore, a preponderance of the evidence is against finding that presumptive service connection for esophageal cancer based on the Veteran's presumed in-service herbicide exposure is warranted. Nonetheless, the unavailability of presumptive service connection for a disability based on exposure to herbicides does not preclude service connection with proof of direct incurrence in service or, based on chronic symptoms in service, a continuity of symptoms since service, or manifestation of a chronic disease to a compensable degree within the first post-service year. See Stefl v. Nicholson, 21 Vet. App. 120 (2007); see also Combee v. Brown, 34 F.3d 1039 (Fed. Cir. 1994). Service connection may be granted for a disability resulting from disease or injury incurred in or aggravated by active military, naval, or air service. 38 U.S.C.A. § 1110; 38 C.F.R. § 3.303(a). Service connection may be granted for any disease diagnosed after discharge, when all the evidence, including that pertinent to service, establishes that the disease was incurred in service. 38 C.F.R. § 3.303(d). As a general matter, service connection for a disability requires evidence of: (1) the existence of a current disability; (2) the existence of the disease or injury in service, and; (3) a relationship or nexus between the current disability and any injury or disease during service. Shedden v. Principi, 381 F.3d 1163 (Fed. Cir. 2004); see also Hickson v. West, 12 Vet. App. 247, 253 (1999), citing Caluza v. Brown, 7 Vet. App. 498, 506 (1995), aff'd, 78 F.3d 604 (Fed. Cir. 1996). The cause of the Veteran's death, esophageal cancer (adenocarcinoma) is a malignant tumor, which is a "chronic disease" listed under 38 C.F.R. § 3.309(a); therefore, the presumptive service connection provisions under 38 C.F.R. § 3.303(b) for service connection based on "chronic" symptoms in service and "continuous" symptoms since service are applicable. Walker v. Shinseki, 708 F.3d 1331 (Fed. Cir. 2013). After review of the lay and medical evidence of record, the Board finds that the evidence weighs against finding that the Veteran's esophageal cancer had its onset during service, manifested to a compensable degree within a year of service separation, or is otherwise causally or etiologically related to the period of active service, including due to chronic symptoms in service. The Board notes that the Veteran complained of vomiting, cough, and abdominal cramps during service. The Veteran's service treatment records reflect diagnoses of strep throat and gastroenteritis in response to the Veteran's in-service complaints. See service treatment records dated in December 1967 and November 1970. However, the Veteran's service treatment records are absent of any complaints, findings, or treatment for esophageal cancer or any tumors. Further, the Veteran's abdomen and viscera were clinically evaluated as normal at the November 1971 service separation examination. On the November 1971 service separation report of medical history, the Veteran checked "No" when asked if he then had or had ever had "throat trouble," "chronic cough," "frequent indigestion," or "tumor." Thus, the medical and lay evidence contemporaneous to service does not show that esophageal cancer, or chronic symptoms related to the diagnosis, manifested during service. The Veteran's own histories and the findings as recorded in service and VA treatment records do not reflect chronic esophageal cancer symptoms in service or continuous esophageal cancer symptoms post-service. VA treatment records dated prior to 2004 do not reflect that the Veteran was diagnosed with esophageal cancer or reflect any report of chronic esophageal cancer symptoms in service, or continuous symptoms since service separation. For treatment purposes the Veteran would be expected to give a full and accurate history. The Board finds it unlikely that the Veteran would report vomiting, cough, diarrhea, abdominal cramps, but not report difficulty or pain when swallowing, had the symptoms been present, when the treatment notes of record are otherwise complete. Kahana v. Shinseki, 24 Vet. App. 428, 438 (2011) (Lance, J., concurring); Cf. AZ v. Shinseki, 731 F.3d 1303 (Fed. Cir. 2013); Buczynski v. Shinseki, 24 Vet. App. 221, 224 (2011); see also Fed. R. Evid. 803(7) (indicating that the absence of an entry in a record may be evidence against the existence of a fact if such a fact would ordinarily be recorded). In December 1967 and November 1970, when the Veteran complained of cough, vomiting, abdominal pain, and diarrhea, there is no indication he reported difficulty or pain when swallowing or tumors of any kind. In none of the clinical visits does the Veteran mention chronic esophageal cancer symptoms in service, or continuous esophageal cancer symptoms since service. If the Veteran had been experiencing these symptoms at the time and believed the symptoms to be related to an in-service event, the Board finds it unlikely that he would not have reported the symptoms and his in-service event, both because he reported other, specific symptoms, and because the reports of history and complaints were being made for treatment purposes. Kahana , 24 Vet. App. at 438; Cf. AZ, 731 F.3d 1303; Buczynski, 24 Vet. App. at 224; see also Fed. R. Evid. 803(7). Because the service medical evidence and lay history by the Veteran was generated contemporaneous to service and is likely to reflect accurately the Veteran's physical state and symptoms during that time, the evidence is of great probative value and weighs against finding that the Veteran had chronic symptoms of esophageal cancer during service. Buczynski at 226-27 (where there is a lack of notation of medical condition or symptoms where such notation would normally be expected, the Board may consider this as evidence that the condition or symptoms did not exist). The Board next finds that the weight of the evidence demonstrates that symptoms of esophageal cancer have not been continuous since separation from service in November 1971. The earliest evidence of cancer is over 30 years after service separation. See September 2004 VA treatment records. While the claims file includes earlier treatment records, they contain no reference to or indication of esophageal cancer. This evidence, in the context of no symptoms or findings in service or at service separation, weighs against finding that a continuity of symptoms of esophageal cancer has manifested since service or that esophageal cancer manifested to a compensable degree within one year of service separation; therefore, presumptive service connection for a chronic disease (i.e., cirrhosis of the liver) is not warranted. See Buchanan, 451 F.3d 1336 (the lack of contemporaneous medical records is one fact the Board can consider and weigh against the other evidence, although the lack of such medical records does not, in and of itself, render the lay evidence not credible). The Board further finds that the weight of the evidence is against finding a direct relationship between esophageal cancer and service. According to the February 2012 VA examination report, the VA examiner characterized the Veteran's cancer as rapidly progressive and stated that the Veteran had increasing problem tolerating oral foods and lost 50 pounds within the 6 months prior to his death. The Veteran's death certificate indicates that the approximate interval/onset regarding the Veteran's esophageal cancer to his death was months. From these facts, the Board reasonably infers that it was the opinion of the medical certification at the time of the Veteran's death that the Veteran's esophageal cancer was not manifested in service and not related to service. If the Veteran did suffer esophageal cancer, or symptoms thereof, in service or since, then the service treatment records, September 2004 VA treatment record, death certificate, and/or the 2012 VA examination report would so indicate. Rather, VA treatment records, the death certificate, and the 2012 VA examination report also reflect that the Veteran's esophageal cancer did not manifest until decades after service in 2004. The appellant does not allege, and the record does not otherwise show, that she has any medical education, training, or experience; therefore, she is a lay witness. 38 C.F.R. § 3.159(a). Lay persons are generally not competent to identify cancer without a diagnosis from a medical professional. Jandreau v. Nicholson, 492 F.3d 1372, 1377, n.4 (Fed. Cir. 2007) (lay persons not competent to diagnose cancer); Rucker, 10 Vet. App. at 74 (stating that a lay person is not competent to diagnose or make a competent nexus opinion about a disorder as complex as cancer). In order for the appellant to report a competent diagnosis of esophageal cancer during service, or at a particular time since service, because the appellant is not competent to diagnose cancer, the evidence must show that the appellant was told by a private doctor that the Veteran had esophageal cancer during service. The record reflects that the Veteran's esophageal cancer was diagnosed decades after service in September 2004 and was indicated by medical opinion evidence to have begun only a few months prior to his death. Thus, the Board finds that any lay statement of esophageal cancer beginning over 30 years prior is not competent evidence of onset of the cancer. The Board affords such statement no probative weight. Finally, the Board finds that the weight of the evidence is against finding that the Veteran's diabetes mellitus and coronary artery disease caused or substantially or materially contributed to the Veteran's death. As noted above, the appellant contends that the Veteran's diabetes mellitus contributed to his cause of death. Diabetes mellitus 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) are deemed associated with herbicide exposure, by VA regulation. The foregoing diseases shall be service connected if a veteran was exposed to a herbicide agent during active military, naval, or air service, if the requirements of 38 C.F.R. § 3.307(a)(6) are met, even though there is no record of such disease during service, provided further that the rebuttable presumption provisions of 38 C.F.R. § 3.307(d) are also satisfied. See 38 C.F.R. § 3.309(e). Under section 3.310(a) of VA regulations, service connection may be established on a secondary basis for a disability which is proximately due to or the result of service-connected disease or injury. 38 C.F.R. § 3.310(a). Establishing service connection on a secondary basis requires evidence sufficient to show (1) that a current disability exists and (2) that the current disability was either (a) proximately caused by or (b) proximately aggravated by a service-connected disability. Allen v. Brown, 7 Vet. App. 439, 448 (1995) (en banc). Where a service-connected disability aggravates a nonservice-connected condition, a veteran may be compensated for the degree of disability (but only that degree) over and above the degree of disability existing prior to the aggravation. Allen, 7 Vet. App. at 448. Temporary or intermittent flare-ups of symptoms of a condition, alone, do not constitute sufficient evidence aggravation unless the underlying condition worsened. Cf. Davis v. Principi, 276 F. 3d 1341, 1346-47 (Fed. Cir. 2002); Hunt v. Derwinski, 1 Vet. App. 292, 297 (1991). According to the 2012 VA examination report and addendum, the VA examiner opined that it is less likely than not that the Veteran's Agent Orange diagnoses, to include diabetes mellitus, hypertension, diabetic retinopathy, coronary artery disease, and prior myocardial infarction, caused or aggravated the Veteran's esophageal cancer. The VA physician explained that, due to the palliative treatment for the cancer and the progression of the cancer itself, the Veteran had problems tolerating oral foods and lost 50 pounds within the 6 month period prior to his death. According to the treatment notes, a rapid decline in functional status and overall health are shown. The VA physician also stated in the rationale that the Veteran's diabetes was fairly well controlled up until the point of being diagnosed with and starting treatment for stage IV esophageal cancer, and the Veteran was started on insulin which could be more easily adjusted to control blood sugars due to his poor oral intake and weight loss/vomiting. The VA physician also noted that the Veteran's blood pressure was fluctuant, but not in the range to compromise any organ function, that there were no cardiac complaints within the year prior to his death, and that a May 2004 echocardiogram showed normal heart function and ejection fraction of 55 percent. Lastly, the VA physician stated that there is no indication anywhere in the medical records that any of the service-connected conditions had any adverse effects on the Veteran's treatment or prognosis, and that there is no evidence in the current literature that the elevated blood sugars/hypertension have any known influence in the overall outcome of this type of rapidly progressive cancer. Although the appellant has asserted that the Veteran's diabetes mellitus contributed to the Veteran's cause of death, she is a lay person and lacks the requisite medical training, expertise, and credentials to provide a competent medical opinion under the facts of this case regarding the relationship between the Veteran's esophageal cancer, which first manifested many years after service, and herbicide exposure related disabilities. The etiology of the Veteran's esophageal cancer is a complex medical etiological question dealing with the origin and progression of cancer and relationship to the digestive system. Adenocarcinoma is diagnosed primarily on clinical findings and physiological testing. Thus, while the appellant is competent to relate symptoms of the Veteran's disability for which she had first-hand knowledge, she is not competent to opine on whether there is a link between the esophageal cancer and active service, including the asserted exposure to herbicide agents or diseases presumptively related to Agent Orange, because such diagnosis and nexus requires specific medical knowledge and training, regarding interrelationship between cancer involving the digestive system and disabilities involving the endocrine system (diabetes mellitus) or circulatory system (retinopathy, hypertension, or coronary artery disease). Cf. Jandreau, 492 F.3d at 1377, n.4 (lay persons not competent to diagnose cancer); see also Rucker at 74 (stating that a lay person is not competent to diagnose or make a competent nexus opinion about a disorder as complex as cancer). Thus, there is no other opinion of record that addresses the question regarding whether the Veteran's diabetes mellitus or coronary artery disease contributed to the Veteran's esophageal cancer, provides a reasoned opinion, provides explanation and logically consistent support for the opinion, and which evinces such a comprehensive understanding of the questions of relationships. As such, the Board finds the February 2012 opinion and its conclusion to be the most probative competent opinion evidence on the question. The evidence of record weighs against a finding that the Veteran had esophageal cancer during service, had a continuity of symptoms of esophageal cancer from service to his death, that esophageal cancer manifested to a compensable degree in the first post-service year, or that esophageal cancer was caused or aggravated by diabetes mellitus or coronary artery disease. Consequently, the appellant's lay assertion of relationship between the cause of the Veteran's death by esophageal cancer and active service is afforded no probative value. In consideration of the foregoing, the Board finds that a preponderance of the lay and medical evidence that is of record weighs against the claim of service connection for the cause of the Veteran's death and, consequently, the claim must be denied. Because the preponderance of the evidence is against the claim, the benefit of the doubt doctrine is not for application. See 38 U.S.C.A. § 5107; 38 C.F.R. § 3.102. ORDER Service connection for the cause of the Veteran's death is denied. ____________________________________________ J. Parker Veterans Law Judge, Board of Veterans' Appeals Department of Veterans Affairs