A descriptive study of second primary malignancies associated to breast cancer in a mexican Hispanic population.

Breast cancer is the second most frequent tumor in Mexico. Patients diagnosed with this cancer have a higher risk of developing a second malignancy. The objective of our study was to see the frequency, types of second cancers, and its impact on survival, in order to be able to deliver a proper and efficient follow up to these patients, because our patients differ from the population of breast cancer in the rest of the world. Our patients are younger and therefore at higher risk. The clinical records of breast cancer patients treated at the Instituto Nacional de Cancerologia Mexico from 1983 to 1992 were reviewed. In 1370 evaluable patients, 77 (5.6%) developed a second neoplasm, of those, 56 (72.7%) in the contralateral breast and 21 in other sites (27.3%), thyroid was the most frequent followed by ovary and endometrium. Mean age of the patients was 51.5 yr, 45.5 for the other breast and 55.5 for other malignancies (p = 0.01). Median survival for all the group was of 180 mo (3-238). Patients were significantly younger in the contralateral breast group, although all our breast cancer patients are younger. The most frequent second malignancy after the other breast, was thyroid followed by ovary and endometrium with similar survival for both groups.