Cancer during pregnancy is uncommon but not rare. Reported rates for most cancers vary widely, reflecting not only differences in populations, but also differing methods of ascertainment and inconsistency of reporting. In a review of more than 4.8 million deliveries in California during a 9-year period, Smith and colleagues (2003) found the incidence of malignant neoplasms during pregnancy or in the subsequent 12 months to be 0.94 per 1000 live births. About a third were diagnosed in the prenatal period and the others within 12 months of delivery. Shown in Table 57-1 are some of the more common cancers associated with pregnancy. Breast, thyroid, and cervical cancers; lymphoma; and melanoma account for at least 85 percent of these malignancies. Although management of the pregnant woman with cancer is problematic, a basic tenet should be followed: she should not be penalized because she is pregnant. That said, treatment must be individualized and include consideration of the type and stage of cancer, her desire to continue the pregnancy, and risks of modifying or delaying treatment.
Table 57-1. Incidence of Malignant Tumors Associated with Pregnancy in 4.85 Million Women |Favorite Table|Download (.pdf)
Table 57-1. Incidence of Malignant Tumors Associated with Pregnancy in 4.85 Million Women
Incidence Per 100,000
Incidence Per Pregnancyb
Surgical intervention for cancer may be indicated for diagnostic, staging, or therapeutic purposes. Most procedures that do not interfere with the reproductive tract are well tolerated by both mother and fetus (see Chap. 41, Surgery during Pregnancy). Although many operative procedures have classically been deferred until after 12 to 14 weeks to minimize abortion risks, this probably is not necessary. Specifically, visualizing a live, normal-appearing fetus with sonography between 9 and 11 weeks forecasts a 95-percent chance that pregnancy will reach viability. We are of the opinion that surgery should be performed regardless of gestational age if maternal well-being is imperiled.
Most diagnostic radiographic procedures have very low x-ray exposure and should not be delayed if they would directly affect therapy (American College of Obstetricians and Gynecologists, 2004). Radiation dosimetry of many procedures is discussed in Chapter 41, Imaging Techniques. Conversely, therapeutic radiation often results in significant fetal exposure. The amount depends on the dose, tumor location, and field size. Although the most susceptible period is during organogenesis, there is no gestational age considered safe ...