Adenocarcinoma of Sigmoid Colon Diagnosed in Pregnancy: A Case Report

With more women getting pregnant at later ages than in the past, the incidence of malignancies in pregnancy is on the rise. Common malignancies of pregnancy are melanoma, breast cancer, cervical cancer, lymphomas, and leukemias. Colorectal carcinoma is rare in pregnancy, with an estimated incidence of 1 in 13',000 cases. We describe such a case of colorectal carcinoma in pregnancy (CRC-p), in a 31-year-old patient. She presented in the 21^st week of her second pregnancy with constipation of two weeks duration despite appropriate medical management. This prompted further evaluation with abdominal imaging revealing partial small bowel obstruction of unclear etiology. She was treated surgically with subtotal colectomy with ileostomy. Pathologic evaluation revealed Stage III B: pT3N2a adenocarcinoma with mucinous features of the sigmoid colon with lymph node metastases. Adjuvant FOLFOX chemotherapy was started in the third trimester and was continued postpartum for a total of 12 cycles. She is doing well, and ileostomy reversal is being planned at the time of writing this. Advancing maternal age is a significant risk factor for CRC-p. Common presenting symptoms in CRC-p include bleeding per rectum, abdominal pain, vomiting, and constipation. The frequent occurrence of many of these symptoms, as well as risks and restrictions associated with diagnostic modalities such as computed tomography scan and colonoscopy during pregnancy, makes the diagnosis challenging. Colonoscopy, followed by pathology evaluation, remains the standard diagnostic method in CRC-p. Management of CRC-p is determined by multiple variables such as the stage of the disease, gestational age, and most importantly, patient wishes. Surgical resection is performed following the diagnosis if the gestational age is less than 20 weeks and delayed until after delivery if gestational age is above 20 weeks. 5-fluorouracil based chemotherapy regimens are used in second and third trimesters, in patients with stage III CRC-p. Prognosis has been reported variably. Despite advanced stages at presentation, most of the studies indicate a similar prognosis compared to CRC in the non-pregnant population. Two-year survival was found to be 64.4% in one case series.