Malignant melanoma associated with breast cancer.

The experience of the population-based Connecticut Tumor Registry was analyzed for the occurrence in the same patient of breast cancer and malignant melanoma. A total of 18,010 women with breast cancer were followed up for the subsequent development of malignant melanoma of the skin or eye. Similarly, 835 women with cutaneous or ocular malignant melanoma were followed up for the subsequent development of breast carcinoma. Survival experience for these cohorts and appropriate Connecticut Tumor Registry incidence rates were used to calculate an expected number of individuals with both types of malignant neoplasms. Twenty-three women had both types of tumors diagnosed at least one month apart. Fewer than 14 such occurrences were expected (P < .05). The two tumors may be related through hormonal factors, particularly when considered with regard to the findings of other laboratory and epidemiologic studies.