Cancer dose-response analysis of the radium dial workers

Bone (46 deaths) and head (19 deaths) cancers have been analyzed using Cox proportional hazard models with cumulative dose treated as a time dependent covariate. For bone cancers, the best models separate the 226Ra and 228Ra isotopes and use a single linear dose-response function with a threshold dose at about 9Gy. Covariates for age-at-first exposure and a tumour latency of 5 years were also important. Head carcinomas depend only on 226Ra, and the best-fitted dose-response function is linear with a threshold at about 5 Gy. For head carcinomas, the inclusion of covariates for age-at-first exposure and tumour latency into the model was not necessary. (orig.)