Radiation and Chemotherapy
Radiation therapy is contraindicated during pregnancy because of its potential for fetal injury. Radiation doses used in cancer therapy are typically
40 to 70 Gy, about 104 to 105 times higher than diagnostic radiation levels. Teratogenic effects
(abnormal fetal development) can result from exposure to radiation in the first 12 weeks of pregnancy, when the embryo is undergoing organogenesis.
Carcinogenic effects may result from exposure to radiation in the second and third trimesters of pregnancy, and these effects are manifested in the first decade of life. National Comprehensive Cancer Network (NCCN) guidelines state that radiotherapy is contraindicated at all stages of pregnancy.
Chemotherapy for the pregnant cancer patient is undertaken using a multidisciplinary approach. Patients should visit an MFM specialist before chemotherapy is initiated, so that the growth and well-being of the fetus and the status of the mother can be monitored. Chemotherapy is contraindicated during the first trimester. Chemotherapy agents inhibit cell division through various mechanisms that may directly or indirectly alter DNA, RNA, and protein synthesis, or microtubule function, leading to induction of apoptosis and cell death.[7,14,16] Cytotoxic agents predominantly affect rapidly dividing cells.
Adverse fetal effects of receiving chemotherapy during the first trimester are spontaneous abortion, congenital malformations, and premature birth. Leslie et al state that “there is virtually no information about long-term effects such as learning or behavior problems that may result from the chronic prenatal exposure to chemotherapy.” In a 2006 report, researchers concluded that breast cancer can be treated with FAC (5-fluorouracil, doxorubicin(Drug information on doxorubicin), cyclophosphamide(Drug information on cyclophosphamide)) in the adjuvant (n = 32) or neoadjuvant (n = 25) setting during the second and third trimesters of pregnancy without significant short-term complications for the majority of children exposed to chemotherapy in utero, but cautioned that longer follow-up of the children is required to evaluate possible late effects of FAC on cardiac function and fertility. 
Nurses and health care workers strive to make pregnant patients as comfortable as possible during their treatment without harming the fetus, bearing in mind that placental transport of drugs from mother to fetus must be considered beginning with the fifth week of gestation. Patients may experience symptoms common to both pregnancy and chemotherapy (eg, nausea, vomiting, anemia, pain, deep venous thrombosis [DVT], and fatigue); they should be encouraged to practice good self-care, with plenty of rest, proper nutrition, prenatal vitamins, and adequate fluid intake.[7,18]
Nausea and vomiting can be treated with ondansetron (Zofran).[7,19] Ondansetron is reasonably safe to use during the second and third trimesters.[7,20] Recombinant human erythropoietin(Drug information on erythropoietin) (epoetin alfa; Epogen, Procrit) is indicated for chemotherapy-induced anemia. It is always important to check blood pressure during pregnancy. Pregnant patients are given the low-molecular-weight heparin(Drug information on heparin) enaxaparin (Lovenox) for treatment of DVT.
Treatment of infection and cutaneous, pulmonary, cardiac, and renal complications resulting from cancer therapy should be a collaborative effort between the oncologist and the MFM specialist, to adequately treat the patient while reducing the risk to the fetus.
The goal is to provide safe surgical treatment and anesthesia to the mother while minimizing the risk of preterm labor or fetal demise.[7,10] The greatest risk of spontaneous abortion is before the 12th week of gestation. When possible, surgery should be postponed until after the first trimester.[8,21] The ideal time for a patient to undergo surgery is during the second trimester.
Premature labor is more likely to occur during the third trimester. This is a very important risk to consider when deciding when to schedule a surgery. If surgery is being performed after the 24th week, the surgeon and hospital must be prepared to deliver a viable fetus. It is recommended that major surgeries, performed on patients with a viable pregnancy, be undertaken at a hospital with obstetrical and neonatal services.
A multidisciplinary approach is important in surgical planning, and should include the oncologist, surgeon, anesthesiologist, MFM specialist, and the patient. Patients are strongly advised to consult with the MFM specialist prior to surgery. General recommendations of the MFM regarding surgery are:
• Assess fetal heart tones both preoperatively and postoperatively. This is done by one of the gynecologists at our cancer center. Monitoring of the fetus during surgery usually is not necessary.
• Aspirin(Drug information on aspirin) and nonsteroidal analgesics are contraindicated during pregnancy.
• Anesthesia and analgesia can be used as in the nonpregnant state as long as precautions are taken. Pregnant patients are at a greater risk for aspiration with general anesthesia and more apt to have oxygen desaturation.
• Intraoperative mapping using isosulfan blue dye
has not been approved for use in pregnant patients and is contraindicated because anaphylaxis can occur with its use.
It is important to understand the anatomic and physiologic changes during pregnancy. Adequate uteroplacental blood flow, blood pressure, and oxygenation must be maintained. The mother must be positioned correctly during surgery to avoid aortocaval compression, especially in advanced gestation.[7,10,21]
NCCN Guidelines for Breast and Cervical Cancer in Pregnancy