Mammary carcinoma and pregnancy.

Among premenopausal women approximately 7 per cent of newly diagnosed breast cancers are accompanied by pregnancy, with most patients being in the fourth decade of life. The prognosis of these patients, and of those whose cancers are diagnosed soon after pregnancy, is generally less favorable than that of nonpregnant females, but if age and stage of disease are comparable, pregnancy per se has little influence upon prognosis. Mastectomy is as effective for pregnant patients as for others and the chance of spontaneous abortion is small. Therapeutic abortion does not improve the chances for cure of patients with clinically localized cancer. Effective endocrine therapy or chemotherapy for advanced or disseminated breast cancer does require therapeutic abortion, and an early pregnancy is best terminated without delay. For pregnancies near term the decision depends greatly upon the desire of the patient for a child. Unless therapeutic needs are urgent, intervention can often be delayed temporarily without significant deterioration of the patient. Pregnancies subsequent to a mastectomy have little bearing upon continued well-being, and as long as the patient is clinically free of cancer no therapeutic benefit can be expected from interrupting them. A decision for future pregnancies should be individualized with due regard for the risk of recurrence and the desirability of completing one's family while still reasonably young. Progress with the treatment of breast cancer depends in part upon the appreciation that cancers do occur during pregnancy and lactation, that they are best diagnosed early and that they are curable. Pregnancy should neither deter a prompt diagnosis nor delay definitive treatment.