The majority of pregnant women with breast cancer can undergo surgery, chemotherapy, or both, but radiation therapy is generally not advised.
Expectant mothers with breast cancer can be given chemotherapy in their second and third trimesters of pregnancy per standard guidelines for nonpregnant women. There is no evidence to suggest that chemotherapy administered correctly harms the fetus, according to a review of meta-analyses, previous systematic reviews, retrospective case series, and case reports published on the topic in English or German between 1980 and mid-2011 (Lancet. 2012;379:570-579).
Core biopsy under local anesthesia, the standard examination used to obtain a histologic diagnosis, can be done safely during pregnancy with a sensitivity of approximately 90%. The information included in the review indicated that breast cancer during pregnancy is not an emergency and the time needed to consult an expert team does not worsen the prognosis, nor is termination of the pregnancy likely to improve the woman’s outcome. The multidisciplinary team should discuss a diagnostic strategy that minimizes fetal radiation exposure, and then determine the best treatment approach, which should adhere as closely as possible to standard protocols for nonpregnant patients.
Most pregnant women are diagnosed with infiltrating ductal adenocarcinomas, which often are aggressive. Radiographic examinations to determine disease stage are possible in pregnancy, but should be performed only when the results will change clinical management. If the estimated risk of metastatic disease is low, staging may be postponed until after the woman delivers the baby.
According to the authors of The Lancet review, a major concern in management of breast cancer during pregnancy is premature birth of the baby, but cancer treatment during pregnancy will reduce the need for early delivery. Preterm delivery or unnecessary delay in diagnosis or treatment to the postpartum period should be avoided as there is no apparent survival benefit for women who undergo treatment after delivery. Termination of pregnancy does not seem to improve maternal outcome.
In general, surgery and sentinel lymph node staging can be done safely during any stage of pregnancy. Most women receive chemotherapy after conservative breast surgery, with radiotherapy delayed until after delivery. Chemotherapy is contraindicated until 10 weeks’ gestation to protect the fetus. The decision to administer chemotherapy should follow the same guidelines as for nonpregnant women, taking into account the gestational age and the overall treatment plan, such as timing of surgery and need for radiotherapy. Pregnancy can change the pharmacokinetics of some chemotherapy agents.
Radiotherapy is generally not advised during pregnancy, especially in later stages when the fetus becomes more difficult to shield. Although in most cases, radiotherapy becomes necessary only after the woman has given birth, the need for this treatment should not be used as a reason to deliver the baby prematurely.
The report includes algorithms for treatment of breast cancer diagnosed at different stages of pregnancy.