Citation Nr: 1340431 Decision Date: 12/06/13 Archive Date: 12/20/13 DOCKET NO. 99-18 926 ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in Newark, New Jersey THE ISSUES 1. Entitlement to service connection for nicotine dependence. 2. Entitlement to service connection for postoperative residuals of clear cell odontogenic carcinoma, claimed as secondary to tobacco dependence incurred in service. REPRESENTATION Veteran represented by: Daniel G. Krasnegor, Attorney at Law WITNESS AT HEARING ON APPEAL The Veteran ATTORNEY FOR THE BOARD Debbie A. Breitbeil, Counsel INTRODUCTION The Veteran, who is the appellant, served on active duty from October 1969 to September 1971. This case is before the Board of Veterans' Appeals (Board) on appeal from an April 1999 rating decision by the Department of Veterans Affairs (VA) Regional Office (RO) in Newark, New Jersey, which denied service connection for nicotine dependence and secondary service connection for odontogenic carcinoma. In July 2001, a Travel Board hearing was held before a Veterans Law Judge; a transcript of that hearing is associated with the claims file. In November 2001, the Board remanded the case to the RO for additional development, eliminating the issue of service connection for nicotine dependence and erroneously stating that "mere nicotine dependence is not a disorder for which service connection can be granted." The Veteran's attorney, in an October 2007 written statement, requested that the claim for nicotine dependence be reinstated. Although legislation enacted during the pendency of this appeal prohibits service connection of a disability on the basis that it resulted from disease attributable to the use of tobacco products by a veteran during his or her service, this statute applies only to claims filed after June 9, 1998. See 38 U.S.C.A. § 1103 (West 2002). In the instant case, VA received the Veteran's claims in January 1998, which is prior to the June 9, 1998 date. Because the Veterans Law Judge who conducted the July 2001 hearing retired, the Veteran was offered the opportunity for another hearing before a Veterans Law Judge who would decide his case. In December 2004, a Travel Board hearing was held before the undersigned; a transcript of this hearing is also associated with the claims file. A February 2005 Board decision denied the Veteran service connection for post-operative residuals of clear cell odontogenic carcinoma, claimed as secondary to tobacco dependence incurred in service. He appealed that decision to the United States Court of Appeals for Veterans Claims (Court). A February 2007 Court Memorandum Decision vacated the Board's February 2005 decision and remanded the matter to the Board for readjudication. In February 2008, April 2010, and April 2011, the Board remanded the case to the RO for further development. Then, in March 2013, the Board requested a medical expert opinion from the Veterans Health Administration (VHA) pursuant to 38 C.F.R. § 20.901(a). That opinion has been received, and in July 2013 the Board sent the Veteran a copy of the opinion for his review and any response; the Veteran's representative responded with a written statement in September 2013. FINDINGS OF FACT 1. Nicotine dependence was not shown to have onset in service; the evidence does not show a current diagnosis of nicotine dependence or a diagnosis of a disability attributable to tobacco use resulting from nicotine dependence. 2. Clear cell odontogenic carcinoma was not manifested in service or to a compensable degree within one year following the date of the Veteran's separation from service in September 1971; his clear cell odontogenic carcinoma, first diagnosed after service, is unrelated to an injury, disease, or event in service including tobacco use therein. CONCLUSIONS OF LAW 1. Service connection for nicotine dependence is not warranted. 38 U.S.C.A. §§ 1110, 5107(b) (West 2002); 38 C.F.R. §§ 3.102, 3.303 (2013); VAOPGCPREC 19-97, 62 Fed. Reg. 37954 (1997); VAOPGCPREC 2-93, 58 Fed. Reg. 42746 (1993). 2. Service connection for postoperative residuals of clear cell odontogenic carcinoma, claimed as secondary to tobacco dependence incurred in service, is not warranted. 38 U.S.C.A. §§ 1110, 1112, 1137, 5107(b) (West 2002); 38 C.F.R. §§ 3.303, 3.304, 3.307, 3.309 (2013). REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veterans Claims Assistance Act of 2000 (VCAA) The VCAA, codified in part at 38 U.S.C.A. §§ 5103, 5103A, and implemented in part at 38 C.F.R § 3.159, amended VA's duties to notify and to assist a claimant in developing information and evidence necessary to substantiate the claim. Under 38 U.S.C.A. § 5103(a), VA must notify the claimant of the information and evidence not of record that is necessary to substantiate a claim, which information and evidence VA will obtain, and which information and evidence the claimant is expected to provide. Also, the VCAA notice requirements apply to all five elements of a service connection claim. The five elements are: 1) veteran status; 2) existence of a disability; (3) a connection between the veteran's service and the disability; 4) degree of disability; and 5) effective date of the disability. Dingess v. Nicholson, 19 Vet. App. 473 (2006). The VCAA notice, as required by 38 U.S.C.A. § 5103(a), must be provided to a claimant before the initial unfavorable adjudication by the RO. Pelegrini v. Principi, 18 Vet. App. 112 (2004). The RO provided post-adjudication VCAA notice by letters dated in February 2004 and July 2008. The Veteran was notified of the evidence needed to substantiate claims of service connection; that VA would obtain service records, VA records and records of other Federal agencies; and that he could submit records not in the custody of a Federal agency, such as private medical records or with his authorization VA would obtain any non-Federal records on his behalf. The July 2008 notice included the elements of a service connection claim regarding the effective date of an award and the degree of disability. To the extent that the VCAA notice letters came after the initial adjudication of the claim in April 1999, which was prior to the enactment of the statute, the timing of the notice did not comply with the requirement that the notice must precede the adjudication. The timing defect, however, was cured because after the RO provided content-complying VCAA notice the claims were readjudicated as evidenced by the supplemental statements of the case, dated in January 2009, September 2010, and October 2012. Mayfield v. Nicholson, 444 F.3d 1328 (Fed. Cir. 2006) (Timing error cured by adequate VCAA notice and subsequent readjudication without resorting to prejudicial error analysis.). Furthermore, under 38 U.S.C.A. § 5103A, VA must also make reasonable efforts to assist the claimant in obtaining evidence necessary to substantiate a claim. As is noted above, Board hearings were held before Veterans Law Judges, including the undersigned, in July 2001 and December 2004. In Bryant v. Shinseki, 23 Vet. App. 488 (2010), the United States Court of Appeals for Veterans Claims (Court) held that 38 C.F.R. § 3.103(c)(2) requires that the Veterans Law Judge who conducts a hearing fulfill two duties to comply with the above the regulation. These duties consist of (1) the duty to fully explain the issues and (2) the duty to suggest the submission of evidence that may have been overlooked. Here, during the Board hearings in July 2001 and December 2004, the Veterans Law Judges indicated that the hearings would focus on the issues of service connection for nicotine dependence and for postoperative residuals of clear cell odontogenic carcinoma, claimed as secondary to tobacco dependence incurred in service, and discussed the elements of the claims that were lacking to substantiate the claims. The Veteran was assisted at the hearing by his accredited representative at that time from The American Legion. The representative and the Veterans Law Judges asked questions to ascertain the nature and etiology of the conditions at issue. There was no pertinent evidence identified by the Veteran or his representative that might have been overlooked and that might substantiate the claims. The hearing focused on the elements necessary to substantiate the claims, and the Veteran, through his testimony, demonstrated that he had actual knowledge of the elements necessary to substantiate his claims. Neither the representative nor the Veteran has suggested any deficiency in the conduct of the hearing. Therefore, the Board finds that, consistent with Bryant, the Veterans Law Judge complied with the duties set forth in 38 C.F.R. § 3.103(c)(2). The RO has also obtained the Veteran's service treatment records. The Veteran has submitted various post-service medical records pertaining to his claimed oral carcinoma, to include Randolph Center for Oral & Maxillary Surgery, Northwest Covenant Medical Center, and several medical statements from Dr. McGuire. The Veteran has not identified any additional available evidence, such as VA outpatient records, that remains outstanding. VA has provided the Veteran with examinations to assist him to substantiate his claims. 38 U.S.C.A. § 5103A(d). He was examined by VA in April 2003, June 2003 (opinion only), August 2003 (opinion only), September 2008, January 2009, August 2010 (opinion only), March 2011 (opinion only), October 2011 (opinion only), and July 2012 (opinion only), to determine the nature and etiology of the Veteran's oral carcinoma. However, as the examination/opinion reports were not deemed to be wholly adequate in regard to all questions posed, the Board in March 2013 arranged to have a VHA medical expert provide an opinion, which was received in May 2013. The Veteran was provided a copy of the opinion, and afforded opportunity to respond. The Veteran's representative has argued in a September 2013 statement that the medical opinions of record are still inadequate and that an opinion must be obtained as to whether the Veteran's nicotine dependence began in service. It is contended that VA examiners have not provided sufficient explanation as to why they are unable to render an opinion, and have not stated what information they needed to be able to provide the necessary medical opinion. It is asserted that the VA examiners did not consider the competent and credible lay evidence establishing the Veteran's smoking history and habits while in service. The Board, however, finds that substantial compliance with opinion requests has been made and that in the context of the other medical opinions that were obtained, particularly the VHA opinion, and consideration of the Veteran's statements, a further delay in this case to obtain another opinion is unnecessary for the reasons that follow. The VHA expert did reference the Veteran's smoking history in service but still felt it would be speculative to opine on whether nicotine dependence developed during service. While she did not specify whether there was any additional evidence that might be procured in order to render a non-speculative opinion, she did provide an adequate and persuasive opinion finding that the Veteran's claimed oral cancer was not likely the result of his tobacco use in service. The Veteran was attempting to establish service connection for the oral cancer through his claim of service connection for nicotine dependence, and as the VHA specialist found no nexus between the cancer and the tobacco use, another medical opinion on the nicotine dependence matter would not change the opinion on the oral cancer issue. Moreover, as will be discussed below, the Veteran has not claimed or provided evidence of a nicotine dependence, or a disability caused by such dependence (other than the oral cancer) since he stopped smoking over 20 years ago. An opinion relative to the presence of nicotine dependency in service has no effect on whether there is a current diagnosis of a dependency or a disability caused by the dependency for VA compensation purposes. In short, there was substantial compliance with remand directives, and to delay this case to obtain further comment from an examiner would be pointless because there is no "reasonable possibility" that such assistance would aid the Veteran's nicotine dependence claim. 38 U.S.C.A. § 5103A(d). As there is no indication of the existence of additional evidence to substantiate the claims, the Board concludes that no further assistance to the Veteran in developing the facts pertinent to the claims is required to comply with the duty to assist. Principles of Service Connection Service connection may be granted for disability resulting from disease or injury incurred in or aggravated by active duty. 38 U.S.C.A. § 1110; 38 C.F.R. § 3.303. Where a veteran served 90 days or more of continuous, active service and a chronic disease, such as a malignant tumor, becomes manifest to a degree of 10 percent within one year from the date of separation from service, the disease shall be presumed to have been incurred in service even though there is no evidence of such disease during the period of service. 38 U.S.C.A. § 1112; 38 C.F.R. §§ 3.307, 3.309. Service connection means that the facts, shown by evidence, establish that a particular injury or disease resulting in disability was incurred in service. This may be accomplished by affirmatively showing inception during service. 38 C.F.R. § 3.303(a). For the showing of chronic disease in service there is required a combination of manifestations sufficient to identify the disease entity and sufficient observation to establish chronicity at the time, as distinguished from merely isolated findings or a diagnosis including the word "chronic." Continuity of symptomatology after discharge is required where the condition noted during service is not, in fact, shown to be chronic or where the diagnosis of chronicity may be legitimately questioned. 38 C.F.R. § 3.303(b). Service connection may also be granted for disability shown after service, when all of the evidence, including that pertinent to service, shows that it was incurred in service. 38 C.F.R. § 3.303(d). In regard to tobacco-related claims, on July 22, 1998, the President signed into law a new provision, codified at 38 U.S.C.A. § 1103, essentially barring service connection for disability or death on the basis that a disease or injury is attributable to the use of tobacco products during service. See also 38 C.F.R. § 3.300 (2013). This provision, however, only applies to claims filed after June 9, 1998, and therefore, given the date of this claim, such bans do not apply to the Veteran's claim. The law in effect prior to the revision in 1998 is found in precedent opinions of the VA General Counsel. In VAOPGCPREC 2-93, 58 Fed. Reg. 42746 (1993), it was held that direct service connection for a tobacco-related disability could be established where the evidence demonstrated that an underlying disease or injury was caused by tobacco use during service. VAOPGCPREC 19-97, 62 Fed. Reg. 37954 (1997), expanded on this opinion, stating that service connection could be awarded on a secondary basis based on tobacco use after military service if it was shown that nicotine addiction arose during service and was the proximate cause of the disability or death. See 38 C.F.R. § 3.310. The opinion set forth a two-pronged sequential analysis for determining whether secondary service connection was warranted: (1) The veteran must have acquired a chemical dependence on nicotine during service; and (2) the nicotine dependence must have been the proximate cause of the present disability. VAOPGCPREC 19-97. The General Counsel also stated that, in making determinations on proximate cause, adjudicative personnel must consider whether there is a supervening cause of the claimed disability or death that severs the causal connection to the service-acquired nicotine dependence. It was noted that such supervening causes could include sustained full remission of the service-related nicotine dependence and subsequent resumption of the use of tobacco products, creating a de novo dependence, or exposure to environmental or occupational agents. See also Davis v. West, 13 Vet. App. 178 (1999). Facts and Analysis Initially, the Board notes that it has reviewed all of the evidence in the Veteran's claims file, with an emphasis on the evidence relevant to these appeals. Although the Board has an obligation to provide reasons and bases supporting its decision, there is no need to discuss, in detail, every piece of evidence. Gonzales v. West, 218 F.3d 1378, 1380-81 (Fed. Cir. 2000) (VA must review the entire record, but does not have to discuss each piece of evidence.). Hence, the Board will summarize the relevant evidence, as appropriate, and the Board's analysis will focus specifically on what the evidence shows, or does not show, as to the claims. The Veteran claims that his postoperative residuals of clear cell odontogenic carcinoma are secondary to tobacco use and a nicotine dependence (i.e., a chemical addiction) that began during service. During hearings in October 1999 and July 2001, the Veteran testified that he began smoking cigarettes in service, that he never used any form of tobacco prior to service, and that he became addicted to nicotine in service, such that he was smoking two packs of cigarettes per day by the time he separated from service in September 1971. He further testified that he stopped smoking in approximately 1991 or 1992. An undated letter from the Veteran's mother states that he never smoked prior to entering service and that he told her he began smoking in service. In other statements provided in November 1998, November 2003, January 2004, and December 2012, the Veteran reiterated his smoking history. The Veteran served on active duty from October 1969 to September 1971. His service medical records show no evidence of an oral cancer, smoking, nicotine dependence, or any related disorders. Based on the service treatment records, clear cell odontogenic carcinoma and a nicotine dependence were not shown to have onset in service, and as for the clear cell odontogenic carcinoma, the Veteran has not argued that it was present during service. 38 U.S.C.A. § 1110; 38 C.F.R. § 3.303(a). Given that there is no competent evidence either contemporaneous with or after service that clear cell odontogenic carcinoma was noted, that is, observed, during service, the principles of service connection pertaining to chronicity and continuity of symptomatology under 38 C.F.R. § 3.303(b) do not apply to the oral cancer claim. For this reason, service connection based on continuity of symptomatology under 38 C.F.R. § 3.303(b) is not established for clear cell odontogenic carcinoma. As for nicotine dependence, the lay evidence of record shows that the Veteran began smoking during service and continued for about 20 years after discharge. Whether his smoking history is illustrative of signs or symptoms of a nicotine dependence from the time of service is debatable. Dr. McGuire believed the Veteran's oral cancer resulted from nicotine dependence, but he did not state whether such dependence was a manifestation of the Veteran's two-year smoking history during service or of his 20+ year smoking history after service. The Veteran essentially claims he had symptoms of nicotine dependence from the time of service. Ultimately, a finding of whether or not continuity of symptomatology has been shown in regard to nicotine dependence is not dispositive of the claim of service connection, as will be explained below. After service, private treatment records show that when the Veteran was seen for a routine check-up in May 1996, he mentioned some swelling near his right maxillary canine. Although X-rays were negative, a follow-up visit many days later showed irritation around this area. In September 1996, he was referred to an oral surgeon. Subsequent private procedures to include biopsy resulted in a diagnosis of clear cell odontogenic carcinoma upon testing of the palatal marginal gingiva, by pathology report. Therefore, after service, the earliest record showing the presence of clear cell odontogenic carcinoma was dated in 1996, which is well beyond the one-year presumptive period following separation from service in 1971 (for malignant tumor as a chronic disease under 38 U.S.C.A. § 1112 and 38 C.F.R. §§ 3.307(a)(3), 3.309(a)). As for service connection for clear cell odontogenic carcinoma based on a post-service initial diagnosis under 38 C.F.R. § 3.303(d) after service, there is no competent evidence that the Veteran's oral cancer, first documented after service beyond the one-year presumptive period, pertaining to a chronic disease, is otherwise related to an injury, disease, or event of service origin including tobacco use therein. 38 C.F.R. § 3.304(d). The record contains numerous medical opinions that address whether the Veteran's clear cell odontogenic carcinoma, initially diagnosed in 1996, may be traced back or attributed to the Veteran's in-service tobacco use, which is conceded. These opinions are discussed below, but it is noted that the opinions favorable to the Veteran's claim are derived from the Veteran's dentist, Dr. McGuire, and the opinions unfavorable to his claim are from various VA oral surgeons, oncologists, and a dentist. In assessing the probative value of the medical opinions in the record, greater weight may be placed on one physician's opinion over another depending on factors such as reasoning employed. Gabrielson v. Brown, 7 Vet. App. 36, 40 (1994). The probative value of a medical opinion is also generally based on the scope of the examination or review, as well as the relative merits of the analytical findings, and the probative weight of a medical opinion may be reduced if the physician fails to explain the basis for an opinion. Sklar v. Brown, 5 Vet. App. 140 (1993). Among the factors for assessing the probative value of a medical opinion are the thoroughness and detail of the opinion. Prejean v. West, 13 Vet. App. 444, 448-49 (2000). In a March 1999 letter, Douglas McGuire, D.M.D., noted that the Veteran's dental records dated back to 1956 (which were of record). He indicated that the Veteran was treated by C. Sheft from 1956 to 1984 and by him from 1984 to the present. Dr. McGuire opined that the Veteran's cancer was rare; that he had never seen this condition in non-smokers; and that the cancer was most likely due to smoking. In a November 1999 letter, Dr. McGuire opined that the Veteran's oral cancer resulted from nicotine addiction. To determine the onset and etiology of the Veteran's odontogenic carcinoma, the RO arranged for the Veteran to be examined by a VA oncologist, with the examiner requested to address the following questions: (A) is it at least as likely as not that the Veteran's odontogenic carcinoma developed in service; (B) is it at least as likely as not that the Veteran's odontogenic carcinoma was manifest during the initial post-service year from September 1971 to September 1972; (C) is the Veteran's odontogenic carcinoma otherwise related to service; (D) is it at least as likely as not that cigarette smoking by the Veteran during service from 1969 to 1971 (as opposed to smoking post service) caused his odontogenic carcinoma; and (E) is it at least as likely as not that the Veteran developed nicotine dependence in service. The Veteran underwent a VA dental and oral examination in April 2003 by Alan Mandel, D.D.S., who in a June 2003 addendum report suggested that an oncologist furnish an opinion as to the origin of the Veteran's type of oral cancer. In August 2003, the claims file was reviewed by a VA oncologist, M. Mohit-Tabdtabai, M.D., who noted that clear cell odontogenic carcinoma was derived from odontogenic epithelial cells known as clear cell, and had its origin in the embryonic oral ectoderm of the dental lamina. The oncologist stated the following: histological appearance and biological behavior of this tumor were not necessarily linked; the assessment of the growth potential of this tumor was very difficult; there was not a significant amount of clinical experience available, particularly in cases where the tumor is rare; and the age of the affected patients ranged from the 4th to the 8th decade and was markedly biased in women on a four to one ratio, with only about one-quarter of those occurrences found in the maxilla. The oncologist opined that there was no relationship between the Veteran's smoking and the tumor, in light of all of the available evidence in the literature and his personal experience in treating these tumors of the head and neck origin. The oncologist added that no studies or medical literature had established why odontogenic tumors became cancerous, and that because such tumors may be present at birth, it was impossible to establish the exact time such tumors converted to a malignancy. As the Veteran was not examined by an oncologist who reviewed his claims file and because the August 2003 VA oncologist's opinion was not totally responsive to each of the five questions (enumerated above, A to E), another examination was requested. However, in September 2008, the Veteran was examined by a dentist (and not an oncologist), who was unable to determine from the examination whether there was a relationship between the Veteran's smoking and his oral cancer condition. Thus, in January 2009, the Veteran was examined by Dr. M. Mohit-Tabdtabai, the same VA oncologist who had previously provided a medical opinion. He reiterated that the Veteran had had a rare developmental tumor (particularly so in the upper alveolar ridge), more common in women, which arose from the ectoderm of the dental lamina. He stated that it was "completely different" from the squamous cell cancer of the head and neck origin that has been shown to be related to smoking. He found from a review of the literature and evidence in the file that it was unlikely to be related to smoking or military service. He disagreed with Dr. McGuire's finding that there was evidence in literature to show a correlation between odontogenic carcinoma and smoking. Despite his clear opinion unfavorable to the Veteran's oral cancer claim, the answers were not wholly adequate in that they lacked some explanation. For example, the oncologist did not explain why the fact that the Veteran's tumor was a "developmental tumor" meant the tumor was less likely to be related to smoking; did not reconcile his conclusions with the statement of Dr. McGuire who had only ever seen the Veteran's type of cancer in smokers; and did not provide specific references to the medical literature he reviewed. Also, the oncologist was unable to say when the Veteran developed dependence to tobacco "without speculation," but the oncologist did not explain why such an opinion would be speculative. In An addendum opinion in August 2010, the oncologist furnished additional rationale, which was consistent with the prior opinion given but which was in part still insufficient. Notably, the oncologist did not identify the specific medical literature referred to in the medical opinion. Thus, the Board sought a medical opinion from another VA oncologist, but in a March 2011 statement, Chaitanya Dave, M.D., who is board-certified in hematology/oncology, could not add more to the oncology opinions already offered. He agreed that the Veteran's "tumor" was rare and that literature about it was likewise rare and not based on scientific studies. He suggested that a dentist would be a better adviser than an oncologist in this case (he did not state why he felt this would be so). Dr. Dave felt that Dr. McGuire should be asked about his statement that he had only seen the Veteran's type of oral cancer in smokers and should provide literature that justified smoking as a cause. He cautioned that "cause and effect are two different things." In a statement, received in June 2011, Dr. McGuire reiterated that the Veteran's oral cancer was caused by smoking, asserting that the "Medical Community has already determined that smoking causes oral cancer." He stated that, after his 30 years of experience, he had only ever detected cancer in smokers, and that "[a]ll medical studies have already proven this fact." As to the type of the Veteran's cancer, he felt that it was for the pathologists to comment upon and that his job was to detect the cancer as early as possible. In October 2011, a VA oral surgeon, Kenneth Cheng, D.D.S., furnished an opinion with a list of medical references, followed by an addendum opinion in July 2012. His opinion was responsive to only five of the seven questions posed in an April 2011 Board remand. His opinion was consistent with those of previous VA examiners. He found it was not at least as likely as not that the Veteran's oral cancer developed in service, was manifest during the initial post-service year, or was otherwise related to service (he stated he had not seen any connection of tobacco use as the cause of such cancer in the literature). He further opined that based on his clinical experience treating odontogenic tumors, it was less likely than not that the Veteran's cigarette smoking during service (as opposed to smoking after service) caused his odontogenic carcinoma. He could not answer whether the Veteran developed nicotine dependence in service, not knowing the Veteran's smoking history prior to and post service (he said it would be speculative to state the Veteran's dependence on tobacco developed in service). Due to the incomplete answers or inadequate rationale provided in the latest opinion, the Board referred the case to a VHA medical expert in March 2013, posing essentially the same questions: (A) Is it at least as likely as not that the Veteran's odontogenic carcinoma developed in or was manifest during service?; (B) Is it at least as likely as not that the Veteran's odontogenic carcinoma was manifest during the initial post service year from September 1971 to September 1972?; (C) Is it at least as likely as not that the Veteran's odontogenic carcinoma is otherwise related to his service, to include his use of tobacco therein?; (D) Is it at least as likely as not that cigarette smoking by the Veteran during service from 1969 to 1971 (as opposed to smoking after service) caused the Veteran's odontogenic carcinoma?; (E) Is it at least as likely as not that the Veteran developed nicotine dependence in service? (F) Provide an opinion, with rationale, as to Dr. M. Mohit-Tabdtabai's statement that because the Veteran's tumor was a "developmental tumor," the tumor was less likely to be related to smoking; and (G) Provide an opinion, with rationale, as to Dr. McGuire's statement that he had only ever seen the Veteran's type of cancer in smokers. The specialist was asked to reconcile conclusions with the opinions of March 1999, November 1999, and June 2011 from Dr. McGuire (discussed above). With rationale, the specialist, who is an oral surgeon, explained the conclusions she reached. In simple, clear terms she described the development of odontogenic tumors (and their histologic patterns) and cited to and provided copies of various medical abstracts for reference. She then provided details on what was known of the Veteran's own oral cancer. She explained how it was "very unlikely" that the Veteran's tumor (which largely demonstrated an aggressive clinical course) developed in or manifested during service, or manifested during the initial post-service year. She stated emphatically that it was not likely that the Veteran's oral cancer was otherwise related to his service including tobacco use therein, because there was nothing in the literature that indicated a correlation between the development of odontogenic tumors including clear cell odontogenic carcinoma and the smoking of cigarettes (she noted she could not find any articles or pathology books to show such an association). She referred to the Veteran's statements in the file as to the onset of his smoking during service, but also indicated there was no mention of a smoking history in service treatment records; her conclusion was that it would be speculating for her to make any comment as to whether the Veteran developed nicotine dependence in service, as the Veteran's entire smoking history including after service was not known. She agreed in whole with the opinion of Dr. M. Mohit-Tabdtabai in January 2009 that there was no relationship between the Veteran's smoking and his clear cell odontogenic carcinoma, explaining that his oral cancer was distinguishable from squamous cell carcinoma, which accounted for 94 percent of all oral malignancies and for which extensive research and literature existed to show that tobacco smoking was a factor that increased the risk of developing squamous cell carcinoma. Finally, she addressed the opinions of Dr. McGuire, strongly cautioning that his opinions should not be taken into consideration as he had no credentials to give an opinion on the matter at hand (he was a general dentist) and had not substantiated his statements with any scientific articles. In assessing the probative value of the medical opinions discussed above, the Board accords the most evidentiary weight to that opinion obtained from the VHA specialist in May 2013. She reviewed the Veteran's records, recorded his history, and provided a reasoned conclusion based on the facts gathered and her own medical expertise. She explained the medical principles underlying her conclusions that the oral cancer was not manifest during service or in the first post-service year, indicating in part that the nature of the Veteran's type of oral cancer (i.e., one with an aggressive clinical course) was such that it was unlikely that the Veteran would not have developed symptoms, signs, and/or have metastasis for 25 years. Her conclusions that found the Veteran's oral cancer was not related to smoking were derived from research, resulting in no medical literature to support a correlation with smoking. There is no indication that Dr. McGuire undertook any research on the matter, despite his assertions that the Veteran's oral cancer was likely attributable to smoking. His statements to the effect that he had only ever seen the Veteran's type of rare cancer in smokers were not supported by any literature to justify smoking as the cause. As pointed out by the VA examiner in an August 2010 addendum opinion, the fact that Dr. McGuire has not seen clear cell odontogenic carcinoma in a non-smoker does not mean that the rare tumor was caused by smoking. Dr. McGuire subsequently declared, in a general statement, that the medical community recognized that smoking causes oral cancer (stating that he would leave it up to the pathologists to comment upon the type of cancer). This statement was corroborated by the VHA specialist, but only with respect to the occurrence of squamous cell carcinoma that accounted for the majority of oral cancers, and not with respect to the Veteran's specific type of oral cancer which was rare. Moreover, the VHA specialist gave convincing reasons why Dr. McGuire's statements relating the Veteran's cancer to his smoking should be rejected. In short, the Board finds that the VHA specialist's opinion warrants substantial probative weight, particularly as it involved a careful review of the entire record (including contradictory opinions) and consideration of the degree of likelihood that the Veteran's oral cancer was related to service and particularly tobacco use therein, as claimed. Further, the opinion provided the necessary medical explanation for finding the Veteran's oral cancer was unrelated to service, post-service, or smoking, which was lacking or not always clear in the previous VA opinions. As for the Veteran's statements attributing his clear cell odontogenic carcinoma to tobacco use in service, although he is competent to describe symptoms of his oral cancer, the claimed disability is not a condition under case law where lay observation has been found to be competent. The determinations as to the diagnosis and causation of the Veteran's clear cell odontogenic carcinoma are medical in nature, that is, beyond the capability of lay observation. Where, as here, the questions involve a medical diagnosis not capable of lay observation, and of medical causation, competent medical evidence is required to substantiate the claim because the Veteran as a lay person is not qualified through education, training, and expertise to offer an opinion on a medical diagnosis or on medical causation. For these reasons, the Board rejects the Veteran's statements as competent evidence to substantiate that his clear cell odontogenic carcinoma is related to his period of service, and particularly smoking during service. 38 C.F.R. § 3.159; Jandreau v. Nicholson, 492 F.3d 1372 (Fed. Cir. 2007). In sum, in consideration of the lay and medical evidence, there is no competent evidence of record linking the Veteran's clear cell odontogenic carcinoma, first shown decades after active duty, to any incident of service including tobacco use therein. In view of the foregoing, the preponderance of the evidence is against the claim for service connection for postoperative residuals of clear cell odontogenic carcinoma, and the benefit-of-the-doubt standard of proof does not apply. 38 U.S.C.A. § 5107(b). The Board will now address whether service connection for nicotine dependence is warranted. It finds that it is not. As noted earlier, the lay evidence of record indicates that the Veteran had a history of smoking from the time of service until 1991 or 1992, by his own report. A clear diagnosis of nicotine dependence has not been made, except in the context of Dr. McGuire's comments as to the Veteran's nicotine dependence causing his oral cancer in 1996; there is no evidence of a current nicotine dependence since the Veteran quit the use of tobacco products in the early 1990s. Moreover, VA opinions including the VHA specialist's opinion reflect that resort to speculation was necessary to address whether the Veteran developed nicotine dependence during service. As for these opinions, it is emphasized that service connection may not be based on resort to speculation or remote possibility. 38 C.F.R. § 3.102; Obert v. Brown, 5 Vet. App. 30, 33 (1993). The Board acknowledges that before it can rely on an examiner's conclusion that an etiology opinion would be speculative, the examiner must explain the basis for such an opinion. Jones v. Shinseki, 23 Vet. App. 382, 389-90 (2010). While examiners did not all furnish reasons for their speculative opinions, as is evident in the opinions of Dr. M. Mohit-Tabdtabai in January 2009 and August 2010 and the opinion of Dr. Cheng in October 2011, the VHA specialist in March 2013 provided some rationale, noting the Veteran's reported smoking history in service and the lack of service treatment evidence of such, but asserting that without a full picture of the Veteran's smoking history including after service there would only be speculation on the matter. It appears that she had considered all the assembled evidence and relied on her medical knowledge. For this reason, the Board finds that the Veteran may not be found to have had nicotine dependence during service. In any case, despite the foregoing discussion regarding a speculative opinion on the nicotine dependence issue, the Board notes that the Veteran by his own admission ceased smoking in 1991 or 1992 and has not indicated any ongoing chemical addiction to nicotine since then. Therefore, nicotine dependence, as a disease for compensation purposes, has not been shown currently. Further, the Veteran has not claimed that he currently has a disability attributable to tobacco use resulting from nicotine dependence arising in service (other than clear cell odontogenic carcinoma, which, as earlier discussed, is not shown to be related to tobacco use/smoking). In light of the foregoing, there is no current diagnosis of nicotine dependence or of a disability caused by tobacco use from a nicotine dependence. In the absence of proof of present disability, there is no valid claim of service connection for nicotine dependence. Brammer v. Derwinski, 3 Vet. App. 223, 225 (1992). Accordingly, the appeal in this matter must be denied. ORDER The appeal seeking service connection for nicotine dependence is denied. The appeal seeking service connection for postoperative residuals of clear cell odontogenic carcinoma, claimed as secondary to tobacco dependence incurred in service, is denied. ____________________________________________ George R. Senyk Veterans Law Judge, Board of Veterans' Appeals Department of Veterans Affairs