Medical technology3 min read
Cancer immunotherapy
Immunotherapy helps the immune system fight cancer. Immune checkpoint inhibitors block an “off” signal sent to immune T cells so they can attack cancer cells. It is approved for many cancer types, but only a portion of patients respond.
When a checkpoint protein binds its partner, it sends an "off" signal to T cells; checkpoint inhibitors block this binding, and some act on the PD-1 protein and others on CTLA-4. They are approved for some people with types of cancer including breast, bladder, cervical, colon, head and neck, liver, lung, kidney and skin, including melanoma.
A National Cancer Institute page (2019) notes that immunotherapy has not yet become as widespread as surgery, chemotherapy and radiotherapy, and that only a small proportion of those who receive it respond. It may cause side effects resulting from the activated immune system attacking healthy tissue, including, in rare cases, widespread inflammation and inflammation of the liver, heart muscle or kidneys.
- In widespread clinical use
- Approved for specific uses
- In clinical trials
- Preclinical
- Concept
Approved for some patients in many types of cancer, with a limited proportion responding.
- Immune checkpoint inhibitorsApproved for specific uses
Approved for some patients in several types of cancer.2
Status last checked: · What the maturity levels mean
What is it?
Immunotherapy is a type of cancer treatment that helps the immune system fight cancer; its types include checkpoint inhibitors, T-cell transfer therapy, monoclonal antibodies, treatment vaccines and immune system modulators.
How does it work?
A checkpoint protein binding its partner sends an "off" signal to T cells, and checkpoint inhibitors block this signal so T cells can kill cancer cells; some target PD-1 and others target CTLA-4.
Where is it used today?
Approved for some people with types of cancer including breast cancer, bladder, cervical, colon, head and neck, liver, lung, kidney, and skin including melanoma, and stomach.
Limits and risks
Only a small proportion of those who receive immunotherapy respond to it, and it has not yet become as widespread as surgery, chemotherapy and radiotherapy (according to a 2019 page).
It may cause side effects resulting from the activated immune system attacking healthy tissue; rare ones include widespread inflammation and inflammation of the liver, heart muscle or kidneys.
Common questions
Why don't all patients respond to immunotherapy?
The sources note that only a small proportion respond, and deciding who is likely to benefit is up to the treating team according to the cancer type and its characteristics.1
Questions for your doctor
- Is immunotherapy approved for my cancer type and stage?
- Which side effects should I report immediately?
References
- 1National Cancer Institute (NIH). Immunotherapy for Cancer. www.cancer.gov/about-cancer/treatment/types/immunotherapyHealth agencies & guidelines · Accessed 2026-10-08
- 2National Cancer Institute (NIH). Immune Checkpoint Inhibitors. www.cancer.gov/about-cancer/treatment/types/immunotherapy/checkpoint-inhibitorsHealth agencies & guidelines · Accessed 2026-10-08
Review status: Edited content · Last updated:
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Educational content only — no diagnosis, and no substitute for a clinician.