## Facts

- James Mattern, a World War II veteran, served in the Pacific theater, including areas in or near Southeast Asia, where he lived among the local population and consumed locally prepared food.
- In 1992, he was diagnosed with a rare liver cancer that is uncommon in the United States and Europe but more prevalent in certain Southeast Asian regions; literature associated the disease with regional environmental factors, including a fungus.
- He died in 1993 from the cancer.
- His widow, Dolores Mattern, sought dependency and indemnity compensation and related survivors’ benefits, alleging the fatal cancer was caused by service-related exposure to local food and environmental conditions in Southeast Asia.
- She submitted private treating-physician statements linking the cancer to his Southeast Asia service and medical/epidemiological literature supporting a relationship between the disease and exposure in that region.
- The VA Regional Office denied service connection for the cause of death.
- The Board of Veterans’ Appeals affirmed, finding the claim not well grounded due to an asserted lack of competent nexus evidence.

## Issues

1. Whether the widow’s cause-of-death service-connection claim was well grounded under 38 U.S.C. § 5107(a) based on the submitted medical opinions and scientific/epidemiological literature.
2. Whether medical treatise and epidemiological evidence, when combined with competent medical opinion applying it to the claimant’s facts, can satisfy the nexus component for well groundedness.

## Decision

- The Court of Appeals for Veterans Claims vacated the Board’s determination that the claim was not well grounded.
- The court held that the treating physicians’ opinions, supported by medical and epidemiological literature, made the nexus theory plausible and therefore well grounded.
- The court explained that generic treatise evidence alone is typically too general and inconclusive to establish nexus, but it can support well groundedness when linked to the veteran’s circumstances by competent medical evidence.
- The case was remanded to the Board for further development and readjudication on the merits consistent with the finding that the claim was well grounded.

## Legal Principles

- A well-grounded claim under 38 U.S.C. § 5107(a) requires evidence sufficient to make the claim plausible; at the threshold stage, claimants are not required to prove causation conclusively.
- In a cause-of-death service-connection claim, plausibility depends on competent evidence of a link between service and the condition causing death.
- Generic medical treatise information, standing alone, is generally too general and inconclusive to establish medical nexus.
- Treatise or epidemiological evidence may be probative for well groundedness when it describes relationships with sufficient certainty and is applied to the specific facts by a competent medical professional to show plausible causality grounded in objective facts.
- Adjudicators must distinguish the low plausibility threshold for well groundedness from the later merits determination based on the weight of the evidence.

## Conclusion

The court held that a survivor’s cause-of-death claim is well grounded where competent treating-physician opinions, supported by relevant epidemiological and medical literature, make a service-related nexus plausible; it vacated the Board’s contrary finding and remanded for further proceedings on the merits.


Mattern v. West, 12 Vet. App. 222 (1999)