20 CFR §30.215

An injury, illness, impairment or disease sustained as a consequence of a diagnosed cancer covered by the provisions of § 30.210 must be established with a fully rationalized medical report by a physician that shows the relationship between the injury, illness, impairment or disease and the cancer. Neither the fact that the injury, illness, impairment or disease manifests itself after a diagnosis of a cancer, nor the belief of the claimant that the injury, illness, impairment or disease was caused by the cancer, is sufficient in itself to prove a causal relationship.