210726-175078, 210726-175078

Veteran appealed a March 2021 VA Regional Office denial of service connection for chronic myelomonocytic leukemia with autoimmune hemolytic anemia (CMML-AHA) and for prostate cancer (including as secondary to CMML-AHA).
Veteran alleges in-service toxin exposures (Southeast Asia and flight line: paints, solvents, jet fuel/benzene, oils/lubricants) and denies post-service exposures or family cancer history; service records show aviation duty and service in Japan.
Medical record includes a January 2020 private physician letter diagnosing CMML-AHA and opining exposures "potentially" etiologic; VA found this insufficient to meet the "at least as likely as not" nexus standard.
AOJ did not obtain a VA examination addressing etiology; the Board found this to be a pre-decisional duty-to-assist error under McLendon and AMA procedures.
Because the Veteran elected Board Direct Review under the AMA, the Board is limited to the AOJ record and remanded the claims to the AOJ to obtain VA examinations addressing nexus (including secondary causation), the cited medical literature, and Veteran lay statements, with a requirement for comprehensive rationales.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Service connection for CMML-AHA	In-service toxin exposures caused CMML-AHA	No nexus shown between service and CMML-AHA	Remanded for VA exam to opine whether CMML-AHA is at least as likely as not related to service exposures; insufficient evidence to decide now
Service connection for prostate cancer (including secondary)	Prostate cancer is related to service exposures and/or secondary to CMML-AHA	No nexus established; AOJ denied claim	Remanded for VA exam to address primary and secondary causation, including relationship to CMML-AHA
Duty to assist — failure to obtain VA examination	AOJ should have provided VA exam given evidence suggesting possible service nexus	AOJ did not obtain exam and denied claim	Board found a pre-decisional duty-to-assist error and remanded to AOJ for examinations per McLendon and AMA remand rules
Consideration of lay statements and medical literature	Veteran’s lay reports and submitted literature (e.g., benzene–jet fuel links) support nexus	AOJ did not adequately address or obtain an exam to reconcile these materials	Examiner must consider lay reports and referenced literature and provide a full rationale; lay evidence cannot be rejected solely for lack of medical documentation

McLendon v. Nicholson, 20 Vet. App. 79 (2006) (VA must provide a medical examination or opinion when the record contains evidence indicating that a claimed disability may be associated with service and an opinion is necessary to decide the claim)