Anorectal cancer (anal cancer) is a disease in which cancer cells grow in the tissues of the anus. It is rare, with approximately 5,000 Americans being diagnosed with this cancer each year.
Symptoms of anal cancer include bleeding from the rectum or anus, pain or pressure in the region surrounding the anus, an itching or discharge from the anus, a lump in the region, and a change in bowel habits. Other conditions may also cause these symptoms, so it is important to check with a physician if you have any of these symptoms.
Risk factors for anal cancer include infection with human papillomavirus (HPV; including strains that cause anal or genital warts), infection with HIV/AIDS, use of certain medications after organ transplantation, anal intercourse, multiple sex partners, tobacco use, and being over age 50. Frequent anal soreness, redness, and inflammation, or having anal fissures increases the risk as well.
Diagnosis is based upon physical examination and a full medical history. The examination may include a digital rectal examination, anoscopy or proctoscopy to examine the anus and lower rectum, ultrasound, and colonoscopy to evaluate the rest of the colon. Finally, a biopsy may be taken to check for cancer if an area appears abnormal.
The treatment for anorectal cancer depends on the stage of cancer, and may involve radiation therapy, chemotherapy, and/or surgery. Chemotherapy and radiation are generally the first line of treatment for anal cancers. Radiation may be administered externally or internally using radioactive seeds or catheters placed in or near the cancer. Surgery for small, contained cancer or cancer in the lower part of the bowel is usually done as a local resection, in which diseased tissue is removed along with some surrounding healthy tissue. This procedure can preserve sphincter muscles.
For more extensive cancer, a resection is performed, in which the anus, rectum, part of the lower colon, and lymph nodes are removed. The surgeon then attaches the end of the intestine to an opening, called a stoma, made in the abdomen where stool collects in a bag attached to the outside of the abdomen.