Surgery, radiotherapy and chemotherapy are all used to treat anal cancer.
The prognosis depends on the size and location of the tumor . The outlook is more favorable if the tumors are small (less than 2 in./5 cm), if there is no lymph node involvement or local extension and if the primary tumor is in the anal margin rather than the anal canal. Primary tumors less than 1 in. (2 cm) in size have a better prognosis, as do tumors that are well differentiated (more mature) rather than undifferentiated or poorly differentiated .
Options by Size of Tumor The choice of conservative surgery or radiotherapy (with or without chemotherapy) for anal or perianal cancer depends on the size of the tumor, local invasion and/or lymph node involvement. Radical surgery (an abdominal-perineal resection) is often required for larger or more extensive cancers, and will result in a loss of anal function, a colostomy , and urinary and sexual malfunction. It is reserved for larger or residual cancers.
• Superficial in situ tumors—those that invade less than 1 in. (2 cm) can be treated with local excision or
radiotherapy alone.
• Tumors 1 to 2 in. (2 to 5 cm) are best treated by chemotherapy (5-fluorouracil + mitomycin-C or 5-FU +
cisplatin) plus radiotherapy, leaving surgery for "salvage" therapy. Some physicians still use just
radiotherapy, but most oncologists today use combined chemotherapy and radiotherapy.
• Tumors larger than 2 in. (5 cm) are treated by chemotherapy, radiotherapy and surgery for residual disease.
