Cancer risk following radiotherapy of cervical cancer: A preliminary report

Women treated for cervical cancer were selected for study because (a) doses to body organs following radiotherapy can be accurately determined and vary sufficiently to permit dose-response evaluations, (b) organs remote from the cervix receive low-dose exposures in the range of current scientific interest, (c) treatment is relatively successful and many patients survive long enough to be at risk of late complications of radiotherapy, and (d) several nonexposed groups of women with cervical cancer are also available for comparison. In addition, population-based cancer registries provide an opportunity to inexpensively study large numbers of individuals over many decades. The careful procedures normally used by cancer registries to record second primary cancers facilitate the study of cancer incidence for which a wider view of radiation risk is expected than can be seen in investigations of mortality. Other special features of studies of cervical cancer patients include the ability to assess the effects of very large partial-body exposures, differences in organ sensitivities to radiation, interactions of radiation with biological factors such as age, and the duration of carcinogenic response