Citation Nr: 21007337 Decision Date: 02/09/21 Archive Date: 02/09/21 DOCKET NO. 19-15 645 DATE: February 9, 2021 ORDER Entitlement to service connection for chronic myelogenous leukemia (CML), to include as due to herbicide agent exposure, is granted. FINDING OF FACT The Veteran’s CML is due to in-service herbicide agent exposure. CONCLUSION OF LAW The criteria for entitlement to service connection for CML have been met. 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.303. REASONS AND BASES FOR FINDING AND CONCLUSION The Veteran had qualifying service from May 1967 to February 1969, including in the Republic of Vietnam. This matter comes before the Board of Veterans’ Appeals (Board) on appeal of a March 2018 rating decision by the Department of Veterans Affairs (VA) Regional Office (RO). Within one year of the March 2018 rating action, VA associated new and relevant medical evidence with the claims file. In a May 2018 rating decision, the RO continued the denial of the above claim. In May 2019, the Veteran timely appealed that denial. Although the Veteran did not appeal the March 2018 rating decision, new, relevant medical evidence was added to the claims file within one (1) year of that rating decision. Pursuant to 38 C.F.R. § 3.156 (b), new and material evidence received prior to the expiration of the appeal period will be considered as having been filed in connection with the claim which was pending at the beginning of the appeal period. Therefore, the Board finds that the March 2018 rating decision is the one on appeal. This case was previously remanded by the Board in October 2019. A review of the claims file shows that there has been substantial compliance with the Board’s remand directives. See Stegall v. West, 11 Vet. App. 268 (1998). The case has been returned to the Board for review. Entitlement to service connection for CML is granted The Veteran asserts his CML is due to his exposure to herbicide agents in service. In October 2019, the Board conceded the Veteran’s current disability of CML (diagnosed in November 2017 by Dr. RB) and the Veteran’s in-service exposure to herbicide agents in the Republic of Vietnam. Service connection may be granted for disability resulting from disease or injury incurred in or aggravated by active military service. 38 U.S.C. § 1110; 38 C.F.R. § 3.303. In order to establish a right to compensation for a present disability, a veteran must show: (1) the existence of a present disability; (2) the in-service incurrence or aggravation of a disease or injury; and (3) a causal relationship between the present disability and the disease or injury incurred or aggravated during service. Shedden v. Principi, 381 F.3d 1163, 1167 (Fed. Cir. 2004). VA laws and regulations provide that if a veteran was exposed to an herbicide agent during service, certain diseases associated with herbicide exposure are presumed to be service connected if the disease is manifested to a compensable degree within a specified time period. 38 U.S.C. § 1116 (a)(1); 38 C.F.R. §§ 3.307, 3.309. The Board notes that while CML is not one of the diseases listed under 38 C.F.R. § 3.309 (e) subject to presumptive service connection, the Veteran may establish service connection on a direct basis. Combee v. Brown, 34 F.3d 1039 (Fed. Cir. 1994). The Board notes that there are conflicting medical opinions in the claims file. When the evidence of record contains conflicting medical opinions, it is the responsibility of the Board to assess the credibility and weight to be given to the evidence. Hayes v. Brown, 5 Vet. App. 60, 6970 (1993) (citing Wood v. Derwinski, 1 Vet. App. 190, 19293 (1992)). When evaluating the probative value of a medical opinion, the Board notes that any opinion must be supported by sufficient evidence and cannot necessarily rely solely on the claims file alone. Nieves-Rodriguez v. Peake, 22 Vet. App. 295, 303 (2008). 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; 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). In March 2018 the Veteran submitted an epidemiological article showing an increased risk of death from Agent Orange in Korean Vietnam veterans, including a positive association between CML and herbicide agent exposure. The Veteran’s physician, Dr. A.F., stated in May 2019 it was his opinion that the Veteran’s CML is more likely than not related to his Agent Orange exposure. Dr. A.F. did not provide a rationale; thus, the Board assigns it minimal probative value. In a November 2019 VA medical opinion, the examiner opined that the Veteran’s CML was less likely than not incurred in or caused by the claimed in-service injury, event, or illness. The examiner noted that the Veteran has an established diagnosis of CML with a positive Philadelphia chromosomal abnormality. The examiner stated that exposure to ionizing radiation is the only known risk factor for CML. CML is almost invariably associated with an abnormal chromosome 22, known as the Philadelphia chromosome, which is acquired. The National Academies of Sciences assessed there is inadequate or insufficient evidence to establish an association between herbicide agents and CML. Regarding the Korean Vietnam Agent Orange risk study submitted by the Veteran, the examiner stated the relative risk for CML was 1.55 based on only 15 deaths. This is less than 2, and thus less than 50:50 in any event. The examiner also pointed out this study did not control for other risks. The Board finds the opinion to be adequate in that it provides a full rationale and is based on a review of the record. The Veteran submitted a private medical opinion in August 2020, from C.H., MSN, NP-C, who opined that after a review of the record and medical research, it is at least as likely as not that the Veteran’s CML is a result of prolonged exposure to benzene, an inherent part of herbicide agents. He pointed out that while previous examiners have opined that exposure to radiation is the only known risk factor for CML and “is almost invariably associated with an abnormal chromosome 22 known as the Philadelphia chromosome” there is significant evidence linking benzene, an inherent part of the Agent Orange structure, and CML. He stated CML is a rare form of leukemia, with an incidence of CML in persons up to age 70 is approximately 2 cases per 100,000 and 8-13 cases per 100,000 in persons aged 80 years and older. Due to its rarity, CML cannot be adequately studied in cohort studies, and the available epidemiologic date is largely from case control studies. To counter the November 2019 VA examiner’s contention that ionizing radiation is the only known risk factor for CML, C.H. provided numerous case reports and case series showing a causal relationship between benzene and CML, and hence the Philadelphia chromosome abnormality. C.H. also provided numerous epidemiological studies regarding benzene and CML. Among the studies, a 1996 expanded cohort study of Chinese workers exposed to benzene showed a relative risk for CML of 2.6. Another 2003 Chinese study showed a statistically significant increased relative risk of 2.5 was found for those with CML who had been exposed to benzene, which increased to a relative risk of 5 among those with over 15 years of benzene exposure. The Board notes that the private medical opinion is based on a review of the record and accurate factual premise; it also provides an adequate rationale and cites to medical research. As such, the Board finds it to be adequate and affords significant probative weight to this opinion. The Board notes the November 2019 VA opinion, in part, rejected the Korean Vietnam Agent Orange study submitted by the Veteran because the relative risk of CML from herbicide agents was shown to be only 1.55. The November 2019 VA opinion suggests that a relative risk of 2 or greater amounts to a 50:50 chance of causation. C.H. has provided a positive opinion and has supported the opinion with studies showing an increased relative risk of greater than 2 of acquiring CML from benzene exposure, thus exceeding the 50:50 benchmark proposed by the November 2019 VA examiner. Further, C.H. has explained, that due to CML’s rarity among the population at large, epidemiologic studies have a limited ability to evaluate causal factors of the disease. Upon consideration of the above, the Board concludes that the evidence is at least in equipoise as to whether the Veteran’s CML is related to conceded herbicide agent exposure. Accordingly, the Board must resolve reasonable doubt in the Veteran’s favor and finds that service connection for CML is warranted. 38 U.S.C. § 5107(b); 39 C.F.R § 3.102; Gilbert v. Derwinski, 1 Vet. App. 49 (1990). R. FEINBERG Veterans Law Judge Board of Veterans’ Appeals Attorney for the Board A. St. Laurent, Associate Counsel The Board’s decision in this case is binding only with respect to the instant matter decided. This decision is not precedential and does not establish VA policies or interpretations of general applicability. 38 C.F.R. § 20.1303.