Anal CancerGeneral Information
Stages of Anal Cancer
Treatment by Stage
HIV and Anal Cancer
Anal cancer, an uncommon cancer, is a disease in which cancer (malignant) cells are found in the anus. The anus is the opening at the end of the rectum (the end part of the large intestine) through which body waste passes. Cancer in the outer part of the anus is more likely to occur in men; cancer of the inner part of the rectum (anal canal) is more likely to occur in women. If the anus is often red, swollen, and sore, there is a greater chance of getting anal cancer. Tumors found in the area of skin with hair on it just outside the anus are skin tumors, not anal cancer.
A doctor should be seen if one or more of the following symptoms appear: bleeding from the rectum (even a small amount), pain or pressure in the area around the anus, itching or discharge from the anus, or a lump near the anus.
If there are signs of cancer, a doctor will usually examine the outside part of the anus and give a patient a rectal examination. In a rectal examination, a doctor, wearing thin gloves, puts a greased finger into the rectum and gently feels for lumps. The doctor may also check any material on the glove to see if there is blood in it. The doctor may give the patient general anesthesia, medicine that puts patients to sleep, to continue the examination if pain is felt during it. The doctor may cut out a small piece of tissue and look at it under a microscope to see if there are any cancer cells. This procedure is called a biopsy.
Anal cancer is an uncommon malignancy, accounting for only a small percentage (4%) of all cancers of the lower alimentary tract. Clinical trials have evaluated the roles of chemotherapy, radiation therapy, and surgery in the treatment of this disease.
Overall, the risk of anal cancer is rising, with data suggesting that individuals with human papillomavirus, and male homosexuals in particular, are at increased risk of anal cancer.
The prognosis (chance of recovery) and choice of treatment depend on the stage of the cancer (whether it is just in the anus or has spread to other places in the body) and the patient's general health.
Anal cancer is an often curable disease. The 3 major prognostic factors are site, size, and differentiation (well-differentiated tumors are more favorable than poorly differentiated tumors). Squamous cell (epidermoid) carcinomas make up the majority of all primary cancers of the anus. The important subset of cloacogenic (basaloid transitional cell) tumors constitute the remainder. These two histologic variants are associated with human papillomavirus infection. Adenocarcinomas from anal glands or fistulae formation and melanomas are rare. Treatment of anal melanoma is not included in this summary.Treatment Overview
There are treatments for all patients with anal cancer. Three kinds of treatment are used:
Surgery (taking out the cancer in an operation). Surgery is a common way to diagnose and treat anal cancer. A doctor may take out the cancer using one of the following methods:
Local resection is an operation that takes out only the cancer. Often the ring of muscle around the anus that opens and closes it (the sphincter muscle) can be saved during surgery so that you will be able to pass the body wastes as before.
Abdominoperineal resection is an operation in which the doctor removes the anus and the lower part of the rectum by cutting into the abdomen and the perineum, which is the space between the anus and the scrotum (in men)or the anus and the vulva (in women). A doctor will then make an opening (stoma) on the outside of the body for waste to pass out of the body. This opening is called a colostomy. Although this operation was once commonly used for anal cancer, it is not used as much today because radiation therapy with or without chemotherapy is an equally effective treatment option but does not require a colostomy. If a patient has a colostomy, a special bag will need to be worn to collect body wastes. This bag, which sticks to the skin around the stoma with a special glue, can be thrown away after it is used. This bag does not show under clothing, and most people take care of these bags themselves. Lymph nodes may also be taken out at the same time or in a separate operation (lymph node dissection).
Radiation therapy uses x-rays or other high-energy rays to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external radiation therapy) or from putting materials that produce radiation (radioisotopes) through thin plastic tubes in the area where the cancer cells are found (internal radiation therapy). Radiation can be used alone or in addition to other treatments.
Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by pill, or it may be put into the body by a needle in a vein or muscle. Chemotherapy is called a systemic treatment because the drugs enter the bloodstream, travel through the body, and can kill cancer cells throughout the body. Some chemotherapy drugs can also make cancer cells more sensitive to radiation therapy. Radiation therapy and chemotherapy can be used together to shrink tumors and make an abdominoperineal resection unnecessary. When only limited surgery is required, the sphincter muscle can often be saved.Stages of Anal Cancer
Once anal cancer is found (diagnosed), more tests will be done to find out if cancer cells have spread to other parts of the body. This testing is called staging. To plan treatment, a doctor needs to know the stage of the disease.
A staging system for anal canal cancer that has been described by the American Joint Committee on Cancer (AJCC) and the International Union Against Cancer. Tumors of the anal margin (below the anal verge and involving the perianal hair-bearing skin) are classified with skin tumors. The following stages are used for anal cancer.
Stage 0 or carcinoma-in-situ Stage 0 anal cancer is very early cancer. The cancer is found only in the top layer of anal tissue.
Stage I The cancer has spread beyond the top layer of anal tissue, is smaller than 2 centimeters in diameter (less than 1 inch), but has not spread to the muscle tissue of the sphincter.
Stage II Cancer has spread beyond the top layer of anal tissue and is larger than 2 centimeters in diameter, but has not spread to nearby organs or lymph nodes (small, bean-shaped structures found throughout the body that produce and store infection-fighting cells).
Stage IIIA Cancer has spread to the lymph nodes around the rectum or to nearby organs such as the vagina or bladder.
Stage IIIB Cancer has spread to the lymph nodes in the middle of the abdomen or in the groin, or the cancer has spread to both nearby organs and the lymph nodes around the rectum.
Stage IV Cancer has spread to distant lymph nodes within the abdomen or to organs in other parts of the body.
Recurrent Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may come back in the anus or in another part of the body.Treatment by Stage
Treatments for anal cancer depend on the type of disease, stage of disease, and the patient's age and general health.
Standard treatment may be considered, based on its effectiveness in patients in past studies, or participation in a clinical trial. Not all patients are cured with standard therapy, and some standard treatments may have more side effects than are desired. For these reasons, clinical trials are designed to find better ways to treat cancer patients and are based on the most up-to-date information. Clinical trials are ongoing in most parts of the country for most stages of anal cancer. For more information about clinical trials, call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237); TTY at 1-800-332-8615.
Treatment of Stage 0 Anal Cancer Treatment will probably be local resection to remove all of the cancer.
Treatment of Stage I Anal Cancer Treatment may be one of the following: 1. Local resection to remove all of the cancer. 2. Radiation therapy with or without chemotherapy. Some patients may also receive therapy that involves placing radioactive substances in the tissues surrounding the cancer to destroy the cancer (interstitial radiation therapy). 3. If cancer cells remain following therapy, surgery removing the anus and lower part of the rectum may be performed. An opening will be made for waste to pass of out the body (colostomy) into a disposable bag attached near the colostomy (colostomy bag). 4. If cancer cells remain following therapy, additional chemotherapy plus radiation therapy may be performed. 5. Radiation therapy followed by interstitial radiation therapy.
Treatment of Stage II Anal Cancer Treatment may be one of the following: 1. Local resection to remove all of the cancer. 2. Radiation therapy plus chemotherapy. Some patients may also receive therapy that involves placing radioactive substances in the tissues surrounding the cancer to destroy the cancer (interstitial radiation therapy). 3. If cancer cells remain following therapy, surgery removing the anus and lower part of the rectum may be performed. An opening will be made for waste to pass of out the body (colostomy) into a disposable bag attached near the colostomy (colostomy bag). 4. If cancer cells remain following therapy, additional chemotherapy plus radiation therapy may be performed.
Treatment of Stage IIIA Anal Cancer Treatment may be one of the following: 1. Radiation therapy plus chemotherapy. 2. Surgery to remove the lining around the colon and stomach plus removal of the lymph nodes followed by radiation therapy.
Treatment of Stage IIIB Anal Cancer Treatment will probably be radiation therapy plus chemotherapy followed by surgery. Depending on how much cancer remains following chemotherapy and radiation, surgery to remove the cancer or surgery to remove the anus and the lower part of the rectum (abdominoperineal resection) may be done. During surgery, the lymph nodes in the groin may be removed (lymph node dissection).
Treatment of Stage IV Anal Cancer Treatment may be one of the following: 1. Surgery to relieve symptoms caused by the cancer. 2. Radiation therapy to relieve symptoms caused by the cancer. 3. Chemotherapy and radiation therapy to relieve symptoms caused by the cancer. 4. A clinical trial evaluating new treatments.
Treatment Recurrent Anal Cancer The choice of treatment will be based on what treatment the patient received when the cancer was first treated. If the patient was treated with surgery, radiation therapy may be given if the cancer recurs. If the patient were treated with radiation, surgery may be used if the cancer recurs. The patient may also receive additional chemotherapy and radiation therapy.
Clinical trials are exploring the use of radiation therapy with chemotherapy and/or radiosensitizers to improve local control.HIV and Anal Cancer
The tolerance of patients with human immunodeficiency virus (HIV) and anal carcinoma to standard fluorouracil/mitomycin chemoradiation is not well defined. Patients with pretreatment CD4 counts of less than 200 may have increased acute and late toxic effects; chemoradiation doses may require modification in this subset of patients.