Immunotherapy for Anal Cancer

Immunotherapy is the use of medicines to stimulate a person’s own immune system to recognize and destroy cancer cells more effectively.  

Immune checkpoint inhibitors

An important part of the immune system is its ability to keep itself from attacking normal cells in the body. To do this, it uses “checkpoints” – proteins on immune cells that need to be turned on (or off) to start an immune response. Cancer cells sometimes use these checkpoints to avoid being attacked by the immune system. But drugs that target these checkpoints can be used to treat some people with anal cancer.

Nivolumab (Opdivo) and pembrolizumab (Keytruda) target PD-1, a protein on certain immune cells (called T cells) that normally helps keep these cells from attacking other cells in the body. By blocking PD-1, these drugs boost the immune response against cancer cells. This can shrink some tumors or slow their growth.

Nivolumab and pembrolizumab can be used in people with anal cancer that has spread (metastasized) and whose cancer starts growing after getting at least one type of chemotherapy. 

Nivolumab can be given as an intravenous (IV) infusion every 2 or 4 weeks. Pembrolizumab can be given as an intravenous (IV) infusion every 3 or 6 weeks.

Possible side effects of checkpoint inhibitors

Side effects of these drugs can include fatigue, cough, nausea, itching, skin rash, loss of appetite, constipation, joint pain, and diarrhea.

Other, more serious side effects occur less often.

Infusion reactions: Some people might have an infusion reaction while getting these drugs. This is like an allergic reaction, and can include fever, chills, flushing of the face, rash, itchy skin, feeling dizzy, wheezing, and trouble breathing. It’s important to tell your doctor or nurse right away if you have any of these symptoms while getting these drugs.

Autoimmune reactions: These drugs work by basically removing one of the defenses on the body’s immune system. Sometimes the immune system starts attacking other parts of the body, which can cause serious or even life-threatening problems in the lungs, intestines, liver, hormone-making glands, kidneys, or other organs.

It’s very important to report any new side effects to your health care team as soon as possible. If serious side effects do occur, treatment may need to be stopped and you may get high doses of corticosteroids to suppress your immune system.

More information about immunotherapy

To learn more about how drugs that work on the immune system are used to treat cancer, see Cancer Immunotherapy.

To learn about some of the side effects listed here and how to manage them, see Managing Cancer-related Side Effects.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Czito BG, Ahmed S, Kalady MF, and Eng C. Chapter 64: Cancer of the anal region. In: DeVita VT, Lawrence TS, Rosenberg SA, eds. DeVita, Hellman, and Rosenberg’s Cancer: Principles & Practice of Oncology. 11th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2019.

Goodman KA, Kachnic LA, Czito BG. Chapter 76: Cancer of the anal canal. In: Niederhuber JE, Armitage JO, Doroshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa. Elsevier: 2020.

National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Anal Carcinoma. V.1.2020. Accessed at www.nccn.org/professionals/physician_gls/pdf/anal.pdf on March 24, 2020.

Last Revised: September 9, 2020

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