Challenges to diagnosing colorectal cancer during pregnancy.

QUESTION: My patient is 13 weeks pregnant and has experienced rectal bleeding and vomiting. Should I send her for a colonoscopy to rule out colorectal malignancies or should I wait until after delivery? ANSWER: The data on colorectal cancer in pregnancy are scarce; however, as the presenting features of colorectal cancer overlap with those of pregnancy itself, there is a risk of development of advanced disease, with poorer prognosis at diagnosis. Therefore, it is strongly recommended that this patient, who is in her second trimester, undergo at least a flexible sigmoidoscopy, which is presumed safe during pregnancy, with or without a liver ultrasound and carcinoembryonic antigen detection based on pretest probability according to her other risk factors.