gastrointestinal disorders
Anal Cancer
Diagnosis of Anal Cancer
Sigmoidoscopy or colonoscopy Biopsy A flexible sigmoidoscopy or rigid anoscopy or sigmoidoscopy is done to evaluate the area. Skin biopsy by a dermatologist or surgeon might be needed for lesions near the squamocolumnar junction (Z line). Whenever rectal bleeding occurs, even in patients with obvious hemorrhoids or known diverticular disease, coexisting cancer must be ruled out. Once anal cancer is diagnosed, staging by CT of the chest, abdomen, and pelvis; MRI; or positron emission tomography (PET) is required to rule out metastatic disease. 