that most past claims would not be affected by a reassessment of doses on the basis of the findings described in this report, it believes that some claims that were not granted would have been.
The implications of the committee’s findings on deficiencies in methods of dose reconstruction used in the NTPR program with regard to the number of claims for nonpresumptive diseases that might be granted in the future are similar to those described above. If methods of dose reconstruction were changed to be consistent with these findings, the committee expects that the outcome of most future claims would not be affected. That expectation is based on the presumption that the distribution of doses in future claims will be similar to the distribution in past claims and, therefore, that credible upper bounds of dose to most claimants would be too low for the VA to conclude that the veteran’s disease was as least as likely as not caused by his radiation exposure and thus qualify the veteran for compensation.
Two additional factors that have not been important in the past may affect future claims for compensation. First, the list of presumptive diseases has been expanded to include 21 cancer types (see Section I.B.4). Of the cancer types for which radiation risks have been estimated from studies of the Japanese atomic-bomb survivors (Thompson et al., 1994), only cancers of the rectum, skin, uterus, prostate, and nervous system are now nonpresumptive; of these, skin and prostatic cancer appear frequently in veterans’ claims, but the others apparently are rare. Estimates of the risk per unit dose for these cancers tend to be lower than estimates of risks for many cancers that are presumptive diseases, and this results in higher screening doses that might qualify a veteran for compensation.16
Second, VA is updating its methods of evaluating the probability of causation of radiation-related cancers (see Section III.E). Consequently, the lowest dose that would qualify a veteran for compensation will increase for many cancers. Such increases are a direct result of improvements in the data on cancer risks in humans and attendant decreases in uncertainty in cancer risk estimates (that is, decreases in credible upper bounds of cancer risks per unit dose).
Thus, if methods of dose reconstruction used by the NTPR program are changed to be consistent with the committee’s findings, the effect on future claims for compensation for nonpresumptive diseases is not likely to be substantial. However, the importance of the committee’s findings could increase when veterans file claims for compensation for presumptive diseases. In such cases, requirements for establishing a veteran’s status as a participant are more demand