Imaging • CT and MRI scans of the pelvis to assess local invasion and whether the iliac and groin (inguinal) lymph nodes are involved (30 percent have inguinal metastases and 10 percent have liver metastases at the time of diagnosis). • Rectal ultrasound may help assess local cancer and lymph node invasion. • Pelvic and abdominal ultrasound. • Abdominal CT scan if the liver is enlarged or if liver function tests are abnormal. • Chest x-ray. Endoscopy and Biopsy • Anoscopy/proctosigmoidoscopy under local or general anesthesia if necessary.