Breast cancer and pregnancy.

Previous studies have found a poor prognosis for breast cancer occurring during pregnancy due to the intense hormonal stimulation produced by the pregnancy. In our study of 176 patients, pregnancy did not seem directly to affect the prognosis of breast cancer. Rather, poor survival was related to the patients' youth (less than 40 years old) and to the large number of estrogen receptor-negative tumors. Of the pregnant patients, 71% had estrogen receptor-negative tumors, implying hormonal insensitivity. Terminating the pregnancy on this basis does not seem warranted. Subsequent pregnancies in young patients did not seem to affect survival adversely. Future pregnancy in patients with stage I tumors can be considered after two years. Survival is so poor in patients with stage II or III tumors that subsequent pregnancies should be discouraged for socioethical reasons.