Nulliparity in women with double primary cancers in both breast and endometrium.

A hospital-based diagnostic index revealed 340 women with endometrial carcinoma diagnosed over the 5-year period 1974 to 1979. On later review, 12 had histological evidence of a separate primary in the breast, developing either prior or subsequent to the endometrial primary. Fifty-eight per cent (n = 7) of these women were nulliparous, which was significantly greater than the nulliparity rate of 23% observed in a sample of the remaining women with endometrial cancer. The results from this small study suggest that the association of nulliparity with double primary cancers is greater than with endometrial cancer alone, though the findings need confirmation from the study of a larger series of such patients.