Citation Nr: 1752062 Decision Date: 11/14/17 Archive Date: 11/22/17 DOCKET NO. 10-18 719 ) DATE ) ) On appeal from the Department of Veterans Affairs Regional Office in Houston, Texas THE ISSUE Entitlement to service connection for prostate cancer, to include as due to ionizing radiation exposure. REPRESENTATION Veteran represented by: Texas Veterans Commission WITNESS AT HEARING ON APPEAL The Veteran ATTORNEY FOR THE BOARD M. Wulff, Associate Counsel INTRODUCTION The Veteran served on active duty from March 1951 to December 1954. This matter comes before the Board of Veterans' Appeals (Board) on appeal from a December 2007 rating decision by the Department of Veterans Affairs (VA) Regional Office (RO) in Jackson, Mississippi. In January 2013, the Board remanded the case to afford the Veteran a Board hearing. In July 2013, the Veteran testified at a hearing before the undersigned Veterans Law Judge. A transcript of that proceeding is associated with the record. The Board remanded the case for further development in September 2013 and June 2017. The case has since been returned to the Board for appellate review. This appeal was processed using the Veterans Benefits Management System (VBMS) electronic claims processing system. The Board notes that the Veteran submitted a private medical record after the August 2017 supplemental statement of the case (SSOC) without a waiver of initial consideration by the Agency of Original Jurisdiction (AOJ). However, a review of this evidence reveals that it is either not relevant or is cumulative of evidence previously of record at the time of the August 2017 SSOC. Therefore, a waiver of AOJ review is not required for this claim. This appeal has been advanced on the Board's docket pursuant to 38 C.F.R. § 20.900(c) (2017). 38 U.S.C. § 7107(a)(2) (2017). FINDINGS OF FACT 1. The Veteran was exposed to ionizing radiation during Operation CASTLE from March 1954 to May 1954. 2. The Veteran's prostate cancer did not manifest in service or for many years thereafter and is not otherwise related to his military service, including exposure to ionizing radiation therein. CONCLUSION OF LAW Prostate cancer was not incurred in active service and may not be presumed to have been so incurred. 38 U.S.C. § 1110, 1112, 1113, 1131, 1137, 5103A, 5107 (2012); 38 C.F.R. § 3.102, 3.159, 3.303, 3.307, 3.309, 3.311 (2017). REASONS AND BASES FOR FINDINGS AND CONCLUSION Neither the Veteran nor his representative has raised any other issues with the duty to notify or duty to assist. See Scott v. McDonald, 789 F.3d 1375, 1381 (Fed. Cir. 2015) (holding that "the Board's obligation to read filings in a liberal manner does not require the Board . . . to search the record and address procedural arguments when the veteran fails to raise them before the Board."); Dickens v. McDonald, 814 F.3d 1359, 1361 (Fed. Cir. 2016) (applying Scott to a duty to assist argument). Law and Analysis 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. §§ 1110, 1131. That an injury or disease occurred in service is not enough; there must be chronic disability resulting from that injury or disease. Service connection may also 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). 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 malignant tumors are considered to be a chronic disease for VA compensation purposes, if chronicity in service is not established, a showing of continuity of symptoms after discharge may support the claim. 38 C.F.R. § 3.303 (b), 3.309; Walker v. Shinseki, 708 F.3d 1331 (Fed. Cir. 2013). In addition, for veterans who have served 90 days or more of active service during a war period or after December 31, 1946, certain chronic disabilities, including malignant tumors, are presumed to have been incurred in service if they manifested to a compensable degree within one year of separation from service. 38 U.S.C. § 1101, 1112, 1113, 1137; 38 C.F.R. § 3.307, 3.309. Service connection for conditions claimed to be due to exposure to ionizing radiation in service can be established in any of three different ways. See Davis v. Brown, 10 Vet. App. 209, 211 (1997); Rucker v. Brown, 10 Vet. App. 67, 21 (1997). First, service connection may be presumptively established for specific diseases that are manifest in radiation-exposed veterans. 38 U.S.C. § 1112 (c); 38 C.F.R. § 3.309 (d). A "radiation-exposed veteran" is defined by 38 C.F.R. § 3.309(d)(3) as a veteran who, while serving on active duty or on active duty for training or inactive duty training, participated in a radiation-risk activity. A "radiation-risk activity" includes the onsite participation in a test involving the atmospheric detonation of a nuclear device. 38 C.F.R. § 3.309(d)(3)(ii)(A). The term "onsite participation" means presence at the test site, or performance of military duties in connection with ships, aircraft, or other equipment used in direct support of the nuclear test, during the official operational period of an atmospheric nuclear test. 38 C.F.R. § 3.309 (d)(3)(iv)(A). For tests conducted by the United States, the term "operational period" for Operation CASTLE means the period March 1, 1954, through May 31, 1954. 38 C.F.R. § 3.309 (d)(3)(v)(J). Diseases presumptively service connected for radiation-exposed veterans under the provisions of 38 U.S.C. § 1112 (c) and 38 C.F.R. § 3.309 (d)(2) are: leukemia (other than chronic lymphocytic leukemia), cancer of the thyroid, cancer of the breast, cancer of the pharynx, cancer of the esophagus, cancer of the stomach, cancer of the small intestine, cancer of the pancreas, multiple myeloma, lymphomas (except Hodgkin's disease), cancer of the bile ducts, cancer of the gall bladder, primary liver cancer (except if cirrhosis or hepatitis B is indicated), cancer of the salivary glands, cancer of the urinary tract; bronchiolo-alveolar carcinoma; cancer of the bone; cancer of the brain; cancer of the colon; cancer of the lung; and cancer of the ovary. 38 U.S.C. § 1112(c)(2); 38 C.F.R. § 3.309(d). Second, if a claimant does not qualify as a "radiation-exposed veteran" under 38 C.F.R. § 3.309(d)(3) and/or does not suffer from one the presumptive conditions listed in 38 C.F.R. § 3.309(d)(2), a veteran may still benefit from the special development procedures provided in 38 C.F.R. § 3.311 if the veteran suffers from a radiogenic disease and claims exposure to ionizing radiation in service. Under 38 C.F.R. § 3.311, "radiogenic disease" means a disease that may be induced by ionizing radiation. 38 C.F.R. § 3.311(b)(2). Prostate cancer is listed as a radiogenic disease. 38 C.F.R. § 3.311(b)(2)(xxiii). Section 3.311(b)(5) requires that prostate cancer become manifest five years or more after exposure. 38 C.F.R. § 3.311(b)(5)(iv). Under the special development procedures in § 3.311(a), dose data will be requested from the Department of Defense in claims based upon participation in atmospheric nuclear testing, and claims based upon participation in the American occupation of Hiroshima or Nagasaki, Japan, prior to July 1, 1946. 38 C.F.R. § 3.311 (a)(2). In all other claims, 38 C.F.R. § 3.311 (a) requires that a request be made for any available records concerning the Veteran's exposure to radiation. These records normally include, but may not be limited to, the Veteran's Record of Occupational Exposure to Ionizing Radiation (DD Form 1141), if maintained; service medical records; and other records which may contain information pertaining to the Veteran's radiation dose in service. All such records will be forwarded to the Under Secretary for Health, who will be responsible for preparation of a dose estimate, to the extent feasible, based on available methodologies. 38 C.F.R. § 3.311(a)(2)(iii). When it has been determined that: (1) a veteran has been exposed to ionizing radiation as a result of participation in the atmospheric testing of nuclear weapons; (2) the veteran subsequently develops a specified radiogenic disease; and, (3) the disease first becomes manifest five years or more after exposure, the claim will be referred to the VA Under Secretary for Benefits for further consideration in accordance with 38 C.F.R. § 3.311 (c). When such a claim is forwarded for review, the VA Under Secretary for Benefits shall consider the claim with reference to 38 C.F.R. § 3.311 (e) and may request an advisory medical opinion from the VA Under Secretary of Health. 38 C.F.R. § 3.311 (b), (c)(1). After referral, the Under Secretary for Benefits must determine whether sound scientific and medical evidence supports a conclusion that it is "at least as likely as not" that the disease resulted from in-service radiation exposure or whether there is "no reasonable possibility" that the disease resulted from such exposure. 38 C.F.R. § 3.311(c)(1). Third, direct service connection can be established under 38 C.F.R. § 3.303 (d) by showing that the disease was incurred during or aggravated by service without regard to the statutory presumptions. See Combee v. Brown, 34 F.3d 1039, 1043-44 (Fed. Cir. 1994). Except as otherwise provided by law, a claimant has the responsibility to present and support a claim for benefits. VA shall consider all information and lay and medical evidence of record in a case and when there is an approximate balance of positive and negative evidence regarding any issue material to the determination of a matter, VA shall give the benefit of the doubt to the claimant. 38 U.S.C. § 5107; 38 C.F.R. § 3.102; Gilbert v. Derwinski, 1 Vet. App. 49, 53 (1990). To deny a claim on its merits, the weight of the evidence must be against the claim. Alemany v. Brown, 9 Vet. App. 518, 519 (1996). In considering the evidence of record under the laws and regulations as set forth above, the Board finds that service connection is not warranted for prostate cancer. The Veteran has contended that his prostate cancer is due to exposure to ionizing radiation during his participation in Operation CASTLE. Specifically, the Veteran has reported that he was stationed at the United States Naval Station at Kwajalein Atoll during five nuclear detonations. In addition, he has recounted that he witnessed the detonation of Test Shot Bravo in March 1954. During a July 2013 hearing, the Veteran testified that he had additional exposure to radiation when he delivered water to a local community in a location where an unexpectedly high amount of radiation was released after the detonation of Test Shot Bravo. The Veteran stated that he was not issued a film badge during service, and he did not recall that any precautions were taken to minimize his exposure to radiation. See, e.g., October 2007 radiation information sheet; November 2007 radiation exposure scenario. In a July 2002 statement, the Veteran reported that he worked for a city public service utility company after service as a meter reader, investigator, and inspector. He retired in 1988. He stated that he smoked approximately one pack of cigarettes per day from the age of 18 to 34 and that he quit around 1963. He indicated that he occasionally smokes a cigar or pipe. The Veteran also reported that his brother was diagnosed with melanoma. In support of his claim, the Veteran submitted internet articles regarding Operation CASTLE. According to a July 2006 article, Test Shot Bravo was the largest accidental nuclear weapon ever detonated by the United States and released energy equivalent to 15 megatons of trinitrotoluene (TNT), which was 250 percent of its predicted yield. It was also noted that local inhabitants of the Marshall Islands were exposed to radiation. In addition, the Veteran submitted an article regarding the effects of radiation. It was noted that a 10 to 50 rem radiation dose to the entire body received in a short period or over a long period would not be expected to show observable health effects, but chances of getting cancer were slightly increased with a radiation dose above 50 rem. It was also noted that there may be short-term blood cell decreases for doses of about 50 rem received in a matter of minutes. The Veteran's service treatment records are negative for any complaints, treatment, or diagnosis of prostate cancer. In fact, his December 1954 separation examination showed a normal clinical evaluation of the abdomen, viscera, and genitourinary system. The post-service private medical records reflect that the Veteran complained of prostate problems in 1979. Thereafter, a January 1986 pathology report showed a diagnosis of adenocarcinoma of the prostate. In addition, a May 2007 private medical record noted that a prostate needle biopsy showed moderately differentiated adenocarcinoma. Therefore, the Veteran has had a diagnosis of prostate cancer during the appeal period. In a July 2007 private medical statement, Dr. G.W. (initials used to protect privacy) reported that the Veteran was under his care for adenocarcinoma of the prostate. Dr. G.W. stated that he was a retired physician of the United States Air Force and Chief of Radiation Sciences for the United States Air Force School of Aerospace Medicine. He indicated that he reviewed a number of case studies for exposure from inhalation of particulate radiation after nuclear weapon detonation and subsequent exposure of military personnel. He stated that the Veteran related a history of being in the Marshall Islands and being exposed to radiation test fallout, which was retrospectively identified as a significant hazard and associated with benign tumors of various types. Dr. G.W. believed that the Veteran's history of exposure to radiation should be taken into account in evaluating his claim for benefits. However, he specifically indicated that he personally did not have any of the pertinent medical records. Initially, the Board notes that the Veteran's service personnel records confirm that he participated in Operation CASTLE during the requisite operational period. However, prostate cancer is not a disease presumptively service connected for radiation-exposed veterans under the provisions of 38 C.F.R. § 3.309(d)(2). Accordingly, the presumptive provisions of 38 C.F.R. § 3.309(d) are not for application in this case. The record shows that the Veteran has been diagnosed with prostate cancer, which is a radiogenic disease as defined under 38 C.F.R. § 3.311(b)(2)(xxiii). In addition, the Veteran has indicated that this radiogenic disease manifested more than five years after his claimed exposure. See 38 C.F.R. § 3.311(b)(5)(iv). Thus, the Veteran was provided with the special development procedures of this section. A September 2001 Personnel Information Exchange System (PIES) response to a request for the Veteran's Record of Occupational Exposure to Ionizing Radiation (DD Form 1141) noted that the document or information requested was not a matter of record. In a December 2006 memorandum, the Chief Public Health and Environmental Hazards Officer, on behalf of the Under Secretary for Health, provided instructions for expedited methodology processing using worst-case dose assessments. The instructions specifically noted that the prostate screening doses developed by the Defense Threat Reduction Agency (DTRA) were based on gamma/beta radiation and needed to be adjusted for neutron and alpha radiation. It was further noted that the adjustments are made by multiplying both the neutron and alpha doses by 4 before adding all the doses together. The adjusted total prostate dose for Pacific Proving Ground cases was listed as 40 rem. In November 2007, DTRA prepared a radiation exposure scenario based on the evidence of record and requested that the Veteran review the scenario for accuracy. The scenario provided a detailed account of the medical and lay evidence of record, including the Veteran's reported exposure to radiation while delivering water to a local community following the detonation of Test Shot Bravo. The Veteran acknowledged that he had the opportunity to review the scenario and agreed that it fully included his best and most current representations on the details of his participation; contained reasonable conditions, estimates, and assumptions to be used for his dose assessment; and that he had no additional information to provide. In December 2007, DTRA confirmed that the Veteran was a participant of Operation CASTLE and provided a radiation dose assessment using an expedited methodology based on worst-case doses. DTRA explained that the expedited process established conservative theoretical maximum doses utilizing actual radiation measurement and technical calculations from atmospheric nuclear test detonations, previously established skin and prostate, bounding assumptions about exposure scenarios, and radiation science fundamentals. It was also noted that the maximum doses were much higher than doses that were estimated in previous radiation dose assessments in order to provide maximum benefit of the doubt to the Veteran and to ensure that the reported doses were not less than actual doses. DTRA further explained that the worst-case parameters and assumptions should adequately encompass any activities that the Veteran performed. Moreover, it was noted that a November 2007 radiation exposure scenario and the Veteran's lay statements were carefully reviewed to ensure that no activities reported would result in a higher dose than that generated through the expedited process. The Veteran's dose estimate was as follows: 18 rem external gamma; 0.5 rem external neutron; 4.5 rem internal committed dose to the prostate (alpha); 2 rem internal committed dose to the prostate (beta plus gamma); and 550 rem total skin dose to any skin area (beta plus gamma). In September 2013, the Board remanded the case to ensure that Veteran's dose estimate fully considered his reported history of radiation exposure. In February 2016, DTRA responded that the dose assessment provided in December 2007 remained current. In October 2016, the Director of Compensation Service requested an advisory opinion from the Under Secretary for Health. In so doing, the Director listed the findings from the December 2007 DTRA dose assessment. She noted that the Veteran was a confirmed participant in the atmospheric nuclear testing that was conducted during Operation CASTLE at the Pacific Proving Ground in 1954. She further noted that surgical pathology reports from January 1986 showed adenocarcinoma of the prostate. She indicated that the Veteran was first exposed to ionizing radiation at age 22 and that his prostate cancer was initially diagnosed 31 years after his first exposure to ionizing radiation. It was also noted that the evidentiary record contained no information concerning post-service employment, family history of cancer, or tobacco use. In addition, the Director of Compensation Service noted that the Veteran testified that he was present at Test Shot Bravo and that he was tasked with delivering water back to the region after it was determined that the water was unsafe due to the unexpectedly high amount of radiation released. She also noted that the Board had indicated that the Veteran's testimony appeared consistent with articles that he submitted indicating that the payload of Test Shot Bravo was 250 percent of its predicted value and that it resulted in environmental contamination. In January 2017, the Director of the Post-9/11 Environmental Health Program provided an advisory opinion on behalf of the Under Secretary for Health. The Director stated that he agreed with the dose estimate provided by DTRA. He explained that it was an upper bound estimate that gave the Veteran great benefit of the doubt and fully quantified the radiation exposure incurred by the Veteran during his participation in Operation CASTLE. The Director of the Post-9/11 Environmental Health Program also stated that the Interactive Radioepidemiological Program (IREP) of the National Institute for Occupational Safety and Health (NIOSH) was used to estimate the likelihood that exposure to ionizing radiation caused the Veteran's prostate cancer. For purposes of the IREP calculation, the Veteran's external radiation doses were assumed to have been received as a single acute dose in the earliest year of exposure. The Director explained that this assumption would tend to increase the probability of causation as calculated by IREP. The program calculated a 99th percentile value for the probability of causation of 22.80 percent for prostate cancer. The Director of the Post-9/11 Environmental Health Program further noted that the Veteran was a confirmed participant in the atmospheric nuclear testing conducted during Operation CASTLE at the Pacific Proving Ground in 1954. He also noted that surgical pathology reports from January 1986 confirmed adenocarcinoma of the prostate. In addition, he indicated that the Veteran was first exposed to ionizing radiation at age 22 and that his prostate cancer was initially diagnosed 31 years after his first exposure to ionizing radiation. Based on the foregoing, the Director of the Post-9/11 Environmental Health Program opined that it was unlikely that the Veteran's prostate cancer was caused by exposure to ionizing radiation in service. In January 2017, the Director of Compensation Service opined that, based on the opinion provided on behalf of the Under Secretary of Health, and following review of the evidence in its entirety, there was no reasonable possibility that the Veteran's prostate cancer resulted from radiation exposure in service. In June 2017, the Board noted that a December 2006 memorandum from the Chief Public Health and Environmental Hazards Officer provided instructions for adjusting prostate screening doses for cases where dose assessments were provided using expedited methodology. The Board remanded the case to clarify whether it was necessary for the Director of Compensation Service and the Director of the Post-9/11 Environmental Health Program to consider adjusted total prostate doses. The Board also remanded the case to ensure that the Under Secretary for Benefits or the Director of Compensation Service had the opportunity to consult the factors set forth in 38 C.F.R. § 3.311(e). In a June 2017 memorandum, the Director of Compensation Service requested an advisory opinion from the Under Secretary for Health. In so doing, the Director provided pertinent information regarding the Veteran's post-service employment, family history of cancer, and tobacco use. Specifically, the Director noted that the Veteran's brother was diagnosed with melanoma; the Veteran worked for a public utility company as a meter reader, investigator, and inspector from 1955 to 1988; and the Veteran had a history of smoking one pack of cigarettes per day from the age of 18 to 34 and occasional cigar smoking. In July 2017, the Director of the Post-9/11 Environmental Health Service provided an advisory opinion on behalf of the Under Secretary for Health. In so doing, the Director specifically indicated that the opinion was provided in response to the June 2017 Board remand and June 2017 memorandum from the Director of Compensation. The Director of the Post-9/11 Environmental Health Service clarified that the reported doses provided by DTRA did not need to be adjusted before performing the IREP calculation. He explained that the adjusted dose of 40 rem should only be considered when using screening tables as part of expedited processing. He further stated that the Under Secretary of Health did not use screening table methodology because it is less accurate than IREP. Moreover, if the screening table methodology was used in the Veteran's case, the dose required to achieve a 50 percent probability of causation would be greater than a 68 rem adjusted dose. The Director of the Post-9/11 Environmental Health Service concluded that the January 2017 advisory medical opinion remained accurate and opined that it was unlikely that prostate cancer was caused by exposure to ionizing radiation while the Veteran was in military service. In so doing, the Director noted the findings from the December 2007 DTRA dose assessment and stated that the IREP calculated a 99th percentile value for the probability of causation of 22.80 percent for prostate cancer. He acknowledged that the Veteran was a confirmed participant in atmospheric nuclear testing conducted during Operation CASTLE at the Pacific Proving Ground in 1954. In addition, he noted that surgical pathology reports from January 1986 confirmed adenocarcinoma of the prostate. He also indicated that the Veteran was first exposed to ionizing radiation at age 22 and that the prostate cancer was initially diagnosed 31 years after his first exposure to ionizing radiation. In July 2017, the Director of Compensation Service observed that the July 2017 opinion from the Under Secretary for Health (Director of the Post-9/11 Environmental Health Service) advised that it was unlikely that the Veteran's prostate cancer resulted from his exposure to ionizing radiation in service. The Director of Compensation Services noted that the Director of the Post-9/11 Environmental Health Service reviewed the additional information contained in the June 2017 memorandum and the Board's June 2017 remand instructions prior to rendering his opinion. She stated that, based on the opinion provided by the Director of the Post-9/11 Environmental Health Service, and following a review of the evidence in its entirety, there was no reasonable possibility that the Veteran's prostate cancer resulted from radiation exposure in service. The Director of Compensation's review of the claims file and consideration of the factors set forth in 38 C.F.R. § 3.311(e) is supported by the information contained in the June 2017 memorandum to the Under Secretary for health, as described above. After review of the evidence of record, the Board assigns substantial probative value to the opinions provided by Director of Compensation and Director of the Post-9/11 Environmental Health Service. The opinions considered the Veteran's medical history, the nature of his exposure to ionizing radiation, and the radiation dose information. The Board does acknowledge that the July 2017 opinion from the Director of the Post-9/11 Environmental Health Service noted that the evidentiary record contained no information concerning the Veteran's post-service employment, family history of cancer, or tobacco use. However, the Director of the Post-9/11 Environmental Health Service specifically indicated that he considered the June 2017 memorandum from the Director of Compensation and the June 2017 Board remand that provided pertinent information regarding such factors. Moreover, the Director of the Post-9/11 Environmental Health Service addressed the factors that he considered most dispositive, including the Veteran's medical history and radiation dose estimates. He also provided a thorough rationale relying on his medical training, knowledge, and expertise. See Nieves-Rodriguez v. Peake, 22 Vet. App. 295, 304 (2008) (most of the probative value of a medical opinion comes from its reasoning). Therefore, the Board finds the opinion to have significant probative value. The Board also acknowledges that the Veteran has contended that his exposure to ionizing radiation was not fully accounted for in the dose estimate obtained by VA. See, e.g., April 2010 substantive appeal. However, the December 2007 DTRA dose estimate was based on conservative theoretical maximum doses utilizing actual radiation measurement and technical calculations from atmospheric nuclear test detonations. Those values were much higher than previous radiation dose assessments, providing maximum benefit of the doubt to the Veteran and ensuring that reported doses were not less than actual doses. In addition, it was noted that a November 2007 radiation exposure scenario was carefully reviewed to ensure that no activities reported would result in a higher dose than that generated through the expedited process. As discussed above, the November 2007 radiation exposure scenario provided a detailed account of the Veteran's exposure to radiation. Indeed, as previously noted, the Veteran specifically acknowledged that it fully included his best and most current representations on the details of his participation. Moreover, in September 2013, the Board remanded the case to ensure that the Veteran's dose assessment fully accounted for his radiation exposure. In February 2016, DTRA indicated that the dose assessment provided in December 2007 remained current. In addition, in July 2017, the Director of the Post-9/11 Environmental Health Service provided a detailed explanation of the DTRA reported doses and clarified that the findings did not need to be adjusted before performing the IREP calculation. The Board also notes that the Veteran has not submitted a specific dose estimate from a credible source that represents a material difference from the dose estimate of record. As such, the claim does not warrant referral to an independent expert (selected by the Director of the National Institute of Health (NIH)) for a separate radiation dose estimate. 38 C.F.R. 3.311(a)(3). Based on the foregoing, the Board finds that the evidence does not warrant a grant of the benefit sought under 38 C.F.R. § 3.311. The Board also finds that service connection for prostate cancer is not warranted on a direct basis. See Combee v. Brown, 34 F.3d 1039, 1043-44 (Fed. Cir. 1994). The Veteran has not contended that his prostate cancer manifested in service or within one year thereafter, nor has there been any allegation that the disorder is related to his military service other than radiation exposure. Moreover, as noted above, the Veteran's service treatment records are negative for any complaints, treatment, or diagnosis of prostate cancer. In addition, the post-service medical record shows that prostate cancer was diagnosed more than 30 years after the Veteran's separation from service. Indeed, the evidence shows that the Veteran was diagnosed in January 1986, and he has not contended otherwise. As such, the Veteran is not entitled to service connection on a presumptive basis, either as a chronic disease during service or within one year of service. 38 U.S.C.A. §§ 1101, 1112, 1113; 38 C.F.R. §§ 3.307(a)(3); 3.309(a); Walker, 708 F.3d 1335-37. Furthermore, the evidence does not show, and the Veteran does not contend, that he had continuity of symptomatology since service. Indeed, the earliest documented medical treatment for complaints of prostate problems was in 1979, and the Veteran was diagnosed with prostate cancer in 1986. In addition to the lack of evidence showing that prostate cancer manifested during service or within close proximity thereto, the weight of the evidence of record does not otherwise link the Veteran's prostate cancer to service. In reaching this determination, the Board has considered the July 2007 private medical statement from Dr. G.W. However, Dr. G.W. merely stated that the Veteran's reported radiation exposure should be taken into consideration. Dr. G.W. expressed no knowledge of the Veteran's radiation dose estimates. Indeed, he specifically stated that he did not personally have access to the pertinent medical records. In addition, although Dr. G.W. stated that he reviewed a number of case studies pertaining to exposure from inhalation of particulate radiation after nuclear weapon detonation and subsequent exposure of military personnel, he did not relate such studies to the Veteran's specific case. Moreover, Dr. G.W. indicated that the Veteran reported having exposure to radiation test fallout that was retrospectively identified as a significant hazard and associated with benign tumors of various types; however, Dr. G.W. he did not specifically address prostate cancer. The Board notes that medical opinions that are speculative, general, or inconclusive in nature do not provide a sufficient basis upon which to support a claim. See e.g. McLendon v. Nicholson, 20 Vet. App. 79, 83 (2006) (doctor's opinion that "it is possible" and "it is within the realm of medical possibility" too speculative to establish medical nexus); Goss v. Brown, 9 Vet. App. 109, 114 (1996) (using the word "could not rule out" was too speculative to establish medical nexus); Warren v. Brown, 6 Vet. App. 4, 6 (1993) (medical opinion expressed only in terms such as "could have been" is not sufficient to reopen a claim of service connection); Tirpak v. Derwinski, 2 Vet. App. 609, 611 (1992) (medical opinion framed in terms of "may or may not" is speculative and insufficient to support an award of service connection for the cause of death); Beausoleil v. Brown, 8 Vet. App. 459, 463 (1996) (a generic statement about the possibility of a link between chest trauma and restrictive lung disease was "too general and inconclusive" to support an award of service connection). Applicable regulations also provide that a finding of service connection may not be based on a resort to speculation or a remote possibility. See 38 C.F.R. § 3.102. Therefore, to the extent that Dr. G.W.'s statement may be considered to be a medical opinion in support of a direct service connection, the Board finds that it has limited probative value. In contrast, the Board affords significant probative value to the opinions provided by the Director of Compensation and Director of the Post-9/11 Environmental Health Service, as these opinions were based on the Veteran's radiation dose estimates and were supported by rationale. In particular, the July 2017 advisory opinion from the Director of the Post-9/11 Environmental Health Service provided detailed information regarding the Veteran's dose assessment and noted that that the IREP program calculated a 99th percentile value for the probability of causation of 22.80 percent for prostate cancer. The Board has also considered the Veteran's and his representative's contentions that his prostate cancer is due to exposure to ionizing radiation during service. Generally, lay persons are competent to report as to the observable symptoms and its history. Jandreau v. Nicholson, 492 F.3d 1372 (Fed. Cir. 2007); Layno v. Brown, 6 Vet. App. 465 (1994); Kahana v. Shinseki, 24 Vet. App. 428, 435 (2011). However, the Veteran and his representative are not competent to provide etiology opinions regarding this issue, as it is a complex medical determination based upon internal medical processes and is not capable of lay observation. Neither the Veteran nor his representative have contended otherwise, and the evidence does not show that they have the medical expertise to provide such opinions. See Jandreau, 492 F.3d 1372; Layno, 6 Vet. App. 465 Nevertheless, even assuming that the Veteran and his representative are competent to opine on this medical matter, the Board finds that the opinions of the Director of the Post-9/11 Environmental Health Service and Director of Compensation have greater probative weight than these more general lay assertions. As noted above, the opinions were based on a substantial review of the relevant evidence of record, including the Veteran's in-service radiation exposure and dose assessment. The opinions were also supported by rationale relying on medical training, knowledge, and expertise. Furthermore, as noted above the Veteran submitted an article that pertained to the effects of radiation exposure. However, the article only provided general information and did not address the specific circumstances of the Veteran's radiation exposure and prostate cancer. The Board finds that the opinions from the Director of Compensation Service and the Director of the Post-9-11 Environmental Health Service are more probative with respect to whether the Veteran's prostate cancer resulted from radiation exposure. For these reasons, the Board finds that the preponderance of the evidence is against the Veteran's claim for service connection for prostate cancer, to include as due to exposure to ionizing radiation. Because the preponderance of the evidence is against the Veteran's claim, the benefit of the doubt provision does not apply. 38 U.S.C. § 5107 (b); Gilbert v. Derwinski, 1 Vet. App. 49, 53 (1990). Accordingly, the Board concludes that service connection for prostate cancer is not warranted. ORDER Entitlement to service connection for prostate cancer, to include as due to exposure to ionizing radiation, is denied. ____________________________________________ J.W. ZISSIMOS Veterans Law Judge, Board of Veterans' Appeals Department of Veterans Affairs