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 2 cm (1 in.) with no evidence of spread to lymph nodes or other organs.
Standard Treatment Small tumors of the skin around the anus and superficial well-differentiated cancers of the anal canal may be adequately treated by local excision with preservation of the sphincter muscle, with or without radiation therapy .