Immunotherapy for Endometrial Cancer

Immunotherapy is treatment with drugs that help a person’s own immune system better recognize and kill cancer cells. Immunotherapy can be used to treat certain types of endometrial cancer that has spread or come back (recurred).

Immune checkpoint inhibitors

An important part of the immune system is its ability to keep itself from attacking the body's normal cells. To do this, it uses “checkpoints” – molecules 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 newer drugs that target these checkpoints hold a lot of promise as cancer treatments. There are lot of clinical trials looking at how these drugs can be used to help treat endometrial cancer.

Pembrolizumab (Keytruda) targets PD-1, a protein on immune system cells called T cells. PD-1 normally helps keep T-cells from attacking other cells in the body. By blocking PD-1, this drug boosts the immune response against cancer cells. This can shrink some tumors or slow their growth.

Pembrolizumab can be used by itself in women with endometrial cancers that are MMR deficient (dMMR) or MSI high (MSI-H). Both of these are linked to high numbers of gene mutations (changes) in the cancer cells. Tumors can be tested for these uncommon changes.

Pembrolizumab can also be used along with the targeted drug lenvatinib (Lenvima) in women with advanced endometrial cancers that are not MMR deficient (dMMR) or MSI high (MSI-H), typically after at least one other drug treatment has been tried.

This immunotherapy drug is given as an intravenous (IV) infusion every 3 weeks.

Possible side effects

Side effects can include fatigue, fever, nausea, headache, skin rash, loss of appetite, constipation, joint/muscle pain, and diarrhea.

Other, more serious side effects occur less often. These drugs work by basically taking the brakes off 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 right away. If you do have a serious side effects, treatment may need to be stopped and you may be given 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.

Arora E, Masab M, Mittar P, et al. Role of Immune Checkpoint Inhibitors in Advanced or Recurrent Endometrial Cancer. Cureus. 2018;10(4):e2521.  

McDonald ME, Bender DP. Endometrial Cancer: Obesity, Genetics, and Targeted Agents. Obstet Gynecol Clin North Am. 2019;46(1):89-105.

Mitamura T, Dong P, Ihira K, Kudo M, Watari H. Molecular-targeted therapies and precision medicine for endometrial cancer. Jpn J Clin Oncol. 2019;49(2):108-120.

National Cancer Institute. Endometrial Cancer Treatment (PDQ®)–Health Professional Version. January 19, 2018. Accessed at on February 22, 2019.

Last Revised: September 17, 2019

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