Breast cancer and pregnancy.

Breast cancer treatment during pregnancy involves a host of psychosocial, ethical, religious, and even legal considerations, as well as medical multidisciplinary decisions, since the effect of treatment on the fetus must be considered. For example, breast or chest wall radiotherapy should be avoided. The absorbed fetal dosage is at least 5 cGy early in pregnancy and increases to several hundred cGy late in pregnancy to the fetal part immediately below the diaphragm. In the second and third trimesters, chemotherapy is associated with intrauterine growth retardation and prematurity in about half of the babies; the risk of birth defects is a concern in the first several weeks. Typical anesthetic agents readily reach the fetus but are not known to be teratogenic. Although abortion will allow full and comprehensive treatment to the mother, it is not known whether the procedure itself is therapeutic. Early in pregnancy, abortion deserves strong consideration, since the effects of treatment on the fetus will not be a consideration. The poor prognosis of pregnancy-associated breast cancer in the past is probably attributable to a combination of initial delay of diagnosis and possibly to unfavorable biologic characteristics of the hormonal milieu of pregnancy. When pregnant patients are matched stage for stage with controls, survivals seem equivalent, although pregnant patients present with more advanced disease.