Any excessive enlargement of the abdomen or the appearance of pressure symptoms should always lead one to make a carul examination, and in not a ew cases a tumour will be ound occupying the pelvic caviy. In rare instances malignant tumours of the rectum may so obstruct the pelvic canal as to render caesarean section imperative.
-J. Whitridge Williams (1903)
Any neoplasm can complicate pregnancy, and as written by Williams, physical examination often suggests the diagnosis. Current imaging also allows a greater number of these to be identiied antepartum. Most encountered neoplasms are benign, and uterine leiomyomas and ovarian cysts are the most frequent.
Cancer has an incidence approximating 1 per 1000 pregnancies (Parazzini, 2017; Salani, 2014). One third are diagnosed prenatally, and the others within 12 months of delivery. Some
FIGURE 63-1 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.) diagnosis, staging, or therapy. Fortunately, most procedures that do not interfere with the reproductive tract are well toler ated by both mother and fetus (Chap. 46, p. 901). Although many operations have classically been deferred until after 12 to 14 weeks' gestation to minimize miscarriage 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 (VTE). In one study, Bleau and coworkers (2016) reported a higher risk ofVTE in gravidas with myeloid leukemia, Hodgkin disease, cervical cancer, and ovarian cancer compared with that in pregnant women without a malignancy.
The risk was not increased in those with brain or thyroid cancer, melanoma, or lymphoid leukemia. That said, current guidelines ing surgeries for cancer. hus, depending on the complexity of the planned procedure, it seems reasonable to use prophylactic low-molecular-weight heparin combined with elastic stockings and/or intermittent pneumatic compression as described in
Chapter 52 (p. 1019).
Sonography is a preferred imaging tool during pregnancy. Even so, according to the American College of Obstetricians and Gynecologists (2017a), most diagnostic radiographic procedures deliver very low x-ray doses and should not be delayed if they would directly afect therapy (Chap. 46, p. 906). Magnetic resonance (MR) imaging can safely be performed in any trimester, but delay until after the irst trimester may lower potential risks. Gadolinium should not be used in the irst trimester and should be used later in pregnancy only when the beneits overwhelmingly outweigh the risks (American College of Radiology, 2016; Kanal, 2013). Computed tomography (CT) is less often selected due to ionizing radiation, and procedure-related doses are listed in Chapter 46 (p. 907). Accordingly, CT is used in pregnancy most often to evaluate acute concerns that include pulmonary embolism, bowel or renal obstruction, and acute neurological events. To enhance CT, oral and intravenous contrasts may be added. hese lack known fetal harm, and postpartum breastfeeding need not be interrupted. Last, some radioisotopes are relatively safe in pregnancy and are listed in Table 46-8 (p. 909).