Carcinoma in situ—a very early, microscopic, non-invasive cancer that has not spread below the membrane of the first layer of anal tissue .
Standard Treatment Surgical removal of the tumor .
Five-Year Survival 100 percent
Stage I
TNM T1, N0, M0
A tumor less than 1 in. (2 cm) found only in the anal mucosa with no evidence of spread to lymph nodes or other organs. There is no sphincter muscle involvement.
Standard Treatment Small tumors of the skin around the anus and of the anal margin may be adequately treated by local excision with or without radiation therapy with preservation of the sphincter muscle.
When surgery that will preserve the sphincter is possible, both radiation and chemotherapy can be used before the operation to reduce the size of the tumor. Selected tumors may also be treated by implanting iridium in the tissue. Careful follow-up is mandatory.