Projected lifetime cancer risks @ C. E. Lanp er ac. A 0.40 1 T 0.35 T 0.35 207 B 0.35 Breast and Thyroid T 0.30 | 0.30 0.30 Solid Tumors other than Breast and Thyroid 0.25 + Probability > = re} o 2 4 | 020+ © 015 |} a 0.10 + 0.05 + 0.5 0.7 1.0 1.5 2.0 3.0 40 0.00 0.5 0.7 DDREF 1.0 1.5 2.0 3.0 4.0 5.0 DDREF Fig. 4. IREP uncertainty distributions for the dose-and-dose-rate effectiveness factors (DDREF) to be applied at low doses and low doserates to risk estimates for (a) breast and thyroid cancer(left panel), and (b) solid cancers other than breast and thyroid (right panel). 0.068 Ta Lognormal Distribution Parameters Mean = 0.170 GM =0.0805 GSD = 3.40 a 0.051 £2 5 8 GM Transfer of estimated excess relative risk to the exposed MI populations The tissue-specific BEIR VII parametric models for ERR (Table 3) apply mainly to the Japanese A-bomb survivor Life Span Study (LSS) cohort studied by the RERF (Preston et al. 2007), which we will denote as 0.034 ERR,ss. Two simple approaches can be used to transfer © a estimated ERR,sx from the population of Hiroshima and Mean 0.017 =e 0.000 PN 0.0 0.2 0.4 0.6 0.8 ERR Fig. 5. Results of a Monte Carlo simulation to evaluate the effects of adjusting an uncertain thyroid cancer excess relative risk (ERR) projection distributed as lognormal with geometric mean (GM) = 0.1197 and geometric standard deviation (GSD) = 3.127, by the DDREFwith uncertainty distribution shown in Fig. 4, left panel. The simulated uncertainty distribution is approximately lognormal with GM = 0.0688 and GSD = 3.40. upon the age/time dependence of the ERR. This is an important consideration for compensation claims adjudication in cases where the claim involves a cancer diagnosed within a few years after exposure, but it has relatively little importance for estimates of lifetime risk. In the present analysis, we follow IREP (NIH 2003; Kocher et al. 2008), using a sigmoid function multiplier like that used in the report of the NIH Ad Hoc Working Group to Develop Radioepidemiological Tables (NIH 1985), which is discussed in the Appendix. For thyroid cancer, the latent period is somewhat shorter than that for other solid cancers, increasing from zero at age | to its full value at 8 years and older (NIH 2003). Nagasaki A-bomb survivors to the MI population. One, called multiplicative transfer, involves assuming that dose-specific ERR values for the MI population (ERR,) are the same as those for the LSS population even though the two populations may have different baseline cancer rates, Le., ERRyg (mult) = ERRss. (1 1) The other, called additive transfer, involves the assump- tion that the product, ERR times the age-specific baseline rate (B), does not vary by population: ERR,ss X Byss = ERRui(add) X Buy; (12) ERRyg(add) = ERR,ss x Brss x Bur. (13) 1.e., The BEIR VII approach uses multiplicative transfer for thyroid cancer, additive transfer for breast cancer, and a weighted average, on the logarithmic scale, with weights of 0.7 on multiplicative transfer and 0.3 on additive transfer, for leukemia, stomach cancer, colon cancer, and for solid cancers other than thyroid, lung, and female breast. For lung cancer, the corresponding weights are 0.3 for multiplicative and 0.7 for additive transfer. The approach used in the present analysis is the same, except that the Monte Carlo weighted averages are on the arithmetic, rather than the logarithmic, scale. We