Neoplasms are commonly found in pregnant women. Although most are benign, if a malignancy complicates pregnancy, then usual management schemes become problematic. Uterine leiomyomas and ovarian cysts are the most frequently encountered benign neoplasms during pregnancy. Malignancies have an incidence of approximately 1 per 1000 pregnancies (Brewer, 2011). One third are diagnosed prenatally and the others within 12 months of delivery. Some of the more common cancers found in pregnant women are shown in Figure 63-1. Of these, the three most common are breast—1 per 5000 pregnancies, thyroid—1 per 7000, and cervical—1 per 8500 (Smith, 2003). These, along with lymphoma and melanoma, account for 65 percent of cancer cases in pregnancy (Eibye, 2013).
Proportion of malignancies during pregnancy and within 12 months of delivery in 4.85 million women from the California Cancer Registry. GI = gastrointestinal. (Data from Smith, 2003.)
Principles of Cancer Therapy Related to Pregnancy
Management of the pregnant woman with cancer poses unique problems related to fetal concerns. Because of these, treatment must be individualized. Considerations include the type and stage of cancer and the desire for pregnancy continuation with the inherent risks associated with modifying or delaying treatment.
Operative procedures indicated for cancer include those for diagnosis, staging, or therapy. Fortunately, most procedures that do not interfere with the reproductive tract are well tolerated by both mother and fetus (Chap. 46, Surgical Procedures During Pregnancy). Although many procedures have classically been deferred until after 12 to 14 weeks’ gestation to minimize abortion risks, this probably is not necessary. We are of the opinion that surgery should be performed regardless of gestational age if maternal well-being is imperiled.
Both pregnancy and malignancy are risk factors for venous thromboembolism. There are no guidelines specific for thromboprophylaxis in pregnant women undergoing surgical procedures for cancer. Thus, depending on the complexity of the planned procedure, it seems reasonable to use mechanical prophylaxis compression or pneumatic stockings, low-molecular-weight heparin, or both (Chap. 52, Thromboprophylaxis). There are general evidenced-based practice guidelines available from the American College of Chest Physicians (Guyatt, 2012).
Sonography is a preferred imaging tool during pregnancy when appropriate. In addition, according to the American College of Obstetricians and Gynecologists (2009), most diagnostic radiographic procedures have very low x-ray exposure and should not be delayed if they would directly affect therapy (Chap. 46, Therapeutic Radiation). Computed tomography is useful for imaging extraabdominal tumors, and abdominal shielding usually helps to decrease fetal exposure. Routine magnetic resonance (MR) imaging use is not recommended, and if needed, is used preferentially after the first trimester. Gadolinium contrast administered with MR imaging ...