What is anal cancer?
Anal cancer arises from the cells around the anal opening or in the anal canal just inside the anal opening. Anal cancer is often a type of cancer called “squamous cell carcinoma”. Other rare types of cancer may also occur in the anal canal and these require consultation with your physician or surgeon to determine the appropriate evaluation and treatment.
Cells that are becoming malignant or “premalignant”, but have not invaded deeper into the skin, are referred to as “high-grade anal intraepithelial neoplasia” or HGAIN (previously referred to by a number of different terms, including “high grade dysplasia”, “carcinoma-in-situ”, “anal intra-epithelial neoplasia grade III”, “high-grade squamous intraepithelial lesion”, or “Bowen’s disease”). While this condition is likely a precursor to anal cancer, this is not anal cancer and is treated differently than anal cancer. Your physician or colon and rectal surgeon can help clarify the differences.
How is anal cancer diagnosed?
Anal cancer is usually found on examination of the anal canal because of the presence of symptoms listed above, on routine yearly physical exams by a physician (rectal exam for prostate check or at the time of a pelvic exam), or on screening tests such as those recommended for preventing or diagnosing colorectal cancer (for example: colonoscopy or lighted scope exam of the colon and rectum or yearly stool blood tests). Anoscopy, or examination of the anal canal with a small, lighted scope, may be performed as well to assess any abnormal findings. If an abnormal area in the anal canal is identified based on the doctor’s exam, a biopsy will be performed to determine the diagnosis. If the diagnosis of anal cancer is confirmed, additional tests to determine the extent of the cancer may be recommended, which may include ultrasounds, Xrays, CT scans, and/or PET scans.
How are anal cancers treated?
Treatment for most cases of anal cancer is very effective in curing the cancer. There are 3 basic types of treatment used for anal cancer:
- Surgery – an operation to remove the cancer
- Radiation therapy – high-dose x-rays to kill cancer cells
- Chemotherapy – giving drugs to kill cancer cells
Combination therapy including radiation therapy and chemotherapy is now considered the standard treatment for most anal cancers. Occasionally, a very small or early tumor may be removed surgically (local excision) without the need for further treatment and with minimal damage to the anal sphincter muscles that are important for bowel control. On occasion, more major surgery to remove the anal cancer is needed, and this requires the creation of a colostomy where the bowel is brought out to the skin on the belly wall where a bag is attached to collect the fecal matter.