The short answer
Most anal cancer that has not spread far is treated with chemoradiation — chemotherapy and radiation given together. This can avoid the larger surgery that removes the anus and rectum. Surgery is generally used for very early tumors, or if cancer remains or returns after chemoradiation. For stage IV disease NCI describes palliative surgery, palliative radiation, and palliative chemotherapy with or without radiation.
Chemoradiation — radiation therapy combined with chemotherapy — is a main treatment NCI lists for stage I, II and III anal cancer.
NCI lists capecitabine, cisplatin, fluorouracil and mitomycin as the chemotherapy drugs used, and says combinations of them may be used.
NCI says the major operation that removes the anus and rectum is used only if cancer remains or comes back after radiation and chemotherapy.
Surgery is generally used for a very small, early tumor. NCI says abdominoperineal resection is used only for cancer that remains or comes back after radiation therapy and chemotherapy.
On this page
Choose how you want to read this
The whole article, with every detail and caution.
This page is for people with anal cancer, and their families, who want an overview of treatment. It covers the main approach, when surgery is used, advanced cancer, HIV, and when to call for help.
The simple version
This page explains how anal cancer is usually treated. It is for people who have just been diagnosed and the people helping them.
Most anal cancer that has not spread far is treated with chemoradiation. That means chemo and radiation given together. NCI says the major surgery is used only if cancer remains or comes back.
The main approach
For stage I, II and III anal cancer, treatment often combines two things.
- Radiation therapy from a machine outside the body. It is aimed at the tumor and nearby lymph nodes. Ask your team how long your own course will run, since NCI does not publish a set number of weeks.
- Chemotherapy, given during the same weeks. NCI lists capecitabine, cisplatin, fluorouracil and mitomycin, and says combinations of them may be used.
NCI lists this pairing for stage I, II and III cancer. Treatment that saves the sphincter muscles lets a person keep control of bowel movements. Ask your team whether your plan does this.
When surgery is used
- A small tumor that has not spread may be removed with local resection. This may save the sphincter muscles.
- Cancer may remain after chemoradiation or come back later. Then a larger operation may be needed. It is called abdominoperineal resection. It removes the anus, rectum, and part of the colon. It also creates a permanent colostomy. That is a surgical opening that lets stool leave the body into a bag.
Advanced or metastatic cancer
Anal cancer can spread to far-off organs. Palliative treatment means treatment aimed at easing symptoms. For stage IV disease NCI lists:
- palliative chemotherapy with or without radiation
- palliative radiation therapy
- palliative surgery to relieve symptoms and improve quality of life
Immunotherapy is one of the options NCI lists when cancer remains or comes back after radiation and chemotherapy.
If you have HIV
NCI says treatment for people who have anal cancer and HIV is generally similar to treatment for other people, with similar outcomes. It adds two cautions. The treatment can further damage an already weakened immune system. And people with a history of AIDS-related complications may need lower doses of anticancer drugs and radiation. So make sure your HIV team and your cancer team talk to each other.
When to get help sooner
Chemoradiation for anal cancer is hard on the skin in the treatment area, on the bowel, and on blood counts. Most side effects are managed, but some need a call right away. An infection while your counts are low can become life-threatening.
- Call 911 or go to an emergency department if you cannot stop heavy bleeding from the rectum, you cannot pass urine or stool at all along with severe belly pain, or you feel faint, confused, or too weak to stand. A temperature of 100.4°F (38°C) or higher, or hard shaking chills, belongs on this line while you are having chemoradiation. CDC treats a fever during chemotherapy as a medical emergency. Chemoradiation lowers your blood counts. At the same time, it breaks down skin around the anus and inflames the bowel. So bacteria have an easy way in, and an infection can move fast. Do not wait for a clinic callback. Go in, and tell them you are on chemoradiation.
- Call your care team the same day if you have seven or more loose stools a day above your normal number, if you cannot keep fluids down, or if you are dizzy and passing little urine. Severe diarrhea can lead to dehydration, which is dangerous.
- Call your care team within a day or two if you notice any of these:
- the skin near the anus or groin is breaking down, weeping, or getting more painful
- you see blood or mucus in your stool
- pain is not controlled by what you were prescribed
- urinating hurts
Do not treat diarrhea with over-the-counter medicine before you check with your team. And do not take fever-reducing medicine before you call, because it can hide an infection.
Sources
Common questions
What is the main treatment for anal cancer?
For stage I, II and III anal cancer, NCI lists external beam radiation therapy given together with chemotherapy. Other options include local resection for some small tumors and radiation alone. Ask your team how many weeks your own course will run.
What chemotherapy drugs are used?
NCI lists four chemotherapy drugs for anal cancer — capecitabine, cisplatin, fluorouracil and mitomycin — and says combinations of them may be used. Ask your team which drugs are in your plan.
Will I need a colostomy?
A permanent colostomy (a surgical opening that lets stool leave the body into a bag) is made during a larger operation called abdominoperineal resection. NCI says this operation is used only for cancer that remains or comes back after radiation therapy and chemotherapy. Ask your team whether it could apply to you.
When is surgery used?
Surgery may be used for a small tumor that has not spread, which can be removed with local resection. It is also used for cancer that remains after chemoradiation or comes back later. In that situation, a more extensive surgery may be needed to remove the anus, rectum, and part of the colon, along with creating a permanent colostomy.
How is advanced or metastatic anal cancer treated?
For stage IV anal cancer, NCI lists palliative chemotherapy with or without radiation, palliative radiation therapy, and palliative surgery. Immunotherapy is listed for cancer that remains or comes back after chemoradiation.
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Last updated: 2026-09-29Next planned review: 2027-08-03
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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