Cancer of the anus or anal canal is rare and its cause is unknown, although it may be linked with infection with human papillomaviruses (HPV), which cause genital warts and are also associated with cervical cancer .
Symptoms of anal cancer usually develop gradually. They may include bleeding from the anus, itching and pain around the anus, a frequent need to defecate or fecal incontinence, a discharge of mucus from the anus, and a lump in or near the anus.
The usual treatment is chemotherapy combined with radiation therapy. In many cases, this causes the tumor to shrink so that surgery is not needed. However, if this treatment is ineffective, surgery to remove the anus and part of the rectum is necessary.