Subsequent mammary and other malignant neoplasms in participants of the Breast Cancer Detection Demonstration Project.

Among 3,528 BCDP-USC screenees, women who had breast cancer before entering the screening program (Group IA) or who had breast cancer detected during the program (Group IB) had a much higher chance of developing a breast cancer later (second primary) than those without any breast cancers (Group II, III, IV). With a median follow-up of seven years after the initial visit (1974-1976), the chances of developing a breast cancer during follow-up study are 24%, 7%, and 0.8% respectively. On the other hand, the chances of developing non-mammary malignancy are not too different between the various cohort groups (2.0-3.3%). Computer analysis of a selected Triad subgroups (487 screenees) also showed that the overall age-specific cancer incidences of our population are similar to that of the 1973-1977 SEER's data. When the relative frequency of specific site of 137 malignancies is concerned, we did see a few more cases of leukemia and melanoma than the SEER's data. However, the number of cases involved is small. Follow-up of all screenees will be continued, and this is only a preliminary report.