Cancer immunotherapy is a type of treatment that helps the immune system recognize, attack, or control cancer cells. Unlike traditional chemotherapy, which directly targets rapidly dividing cells, many immunotherapies work by changing or strengthening immune activity against cancer. Immunotherapy has become an important part of treatment for several cancers, although it does not work for every cancer or every patient. The effectiveness of immunotherapy varies considerably. Some patients experience long-lasting cancer control, while others receive little benefit.
The immune system naturally protects the body from infections and abnormal cells. Cancer can sometimes avoid immune detection or create an environment that suppresses immune activity.
Immunotherapy aims to overcome some of these mechanisms.
Depending on the treatment, immunotherapy may:
The appropriate approach depends on the cancer type, stage, biomarkers, and previous treatments.
One of the best-known approaches involves immune checkpoint inhibitors.
Cancer cells can take advantage of natural immune checkpoints that normally prevent excessive immune activity. By blocking certain checkpoint proteins, immunotherapy can release these brakes and allow T cells to attack cancer cells more effectively.
Important checkpoint pathways include:
Not every tumor responds to checkpoint blockade, which is why biomarker testing and cancer-specific treatment planning can be important.
Checkpoint inhibitors are among the most widely used immunotherapies.
Examples include medicines targeting PD-1, PD-L1, or CTLA-4.
These treatments are used for several cancers, including certain cases of:
The specific medicine and eligibility criteria vary by cancer type.
CAR T-cell therapy is a form of cellular immunotherapy primarily used for certain blood cancers.
T cells are collected from the patient and genetically modified in a laboratory so they can recognize a specific cancer target. The modified cells are then expanded and returned to the patient.
CAR T-cell therapy has been used for selected leukemias, lymphomas, and multiple myeloma.
Some monoclonal antibodies help the immune system recognize cancer cells or interfere with signals that cancer cells need to grow.
Certain antibody treatments also deliver drugs or radioactive material directly toward cancer cells.
Cancer vaccines are being developed to stimulate immune responses against tumor-associated targets.
Some therapeutic cancer vaccines are already used for specific cancers, while personalized cancer vaccines and neoantigen vaccines remain an active area of research.
Other immunotherapies can stimulate or modify immune activity using substances such as cytokines or other immune-regulating agents.
These treatments may be used in specific cancer settings.
Testing tumor tissue can help determine whether immunotherapy may be useful.
Depending on the cancer, doctors may evaluate:
A biomarker result does not guarantee that immunotherapy will work, but it can help inform treatment decisions.
Immunotherapy is used differently across cancer types.
Checkpoint inhibitors can be used alone or with chemotherapy in selected patients with non-small cell lung cancer and other specific lung cancer settings.
Immunotherapy has become an important treatment for advanced melanoma, with checkpoint inhibitors capable of producing durable responses in some patients.
Checkpoint inhibitors and combinations of immunotherapy with targeted medicines are used for certain advanced kidney cancers.
Immunotherapy may be used for selected patients with triple-negative breast cancer, particularly when specific clinical or biomarker criteria are met.
CAR T-cell therapy and other immune-based treatments have transformed care for certain leukemias, lymphomas, and multiple myeloma.
Because immunotherapy changes immune activity, side effects can occur when the immune system attacks healthy tissues.
These are sometimes called immune-related adverse events.
Possible effects include:
Most side effects can be managed more effectively when identified early.
Severe diarrhea, difficulty breathing, persistent fever, significant weakness, yellowing of the skin or eyes, or other unusual symptoms during immunotherapy should be reported promptly to the treating medical team.
CAR T-cell therapy has distinctive risks.
One important complication is cytokine release syndrome (CRS), which can cause fever, low blood pressure, rapid heart rate, and breathing problems.
Another complication is neurological toxicity, sometimes called immune effector cell-associated neurotoxicity syndrome (ICANS).
Because these reactions can become serious, CAR T-cell therapy is administered under specialized medical supervision.
Immunotherapy can produce long-lasting responses in some patients, particularly in certain cancers.
However, it does not cure every cancer and does not work for every patient.
Some tumors initially respond and later develop resistance, while others show little or no response from the beginning.
Researchers are studying combinations of immunotherapy, targeted therapies, chemotherapy, radiation, and other approaches to improve response rates.
Cancer treatment is increasingly based on the biological characteristics of individual tumors.
Genetic testing, immune biomarkers, pathology, and other laboratory information can help determine whether an immunotherapy approach may be appropriate.
This personalized approach can help doctors select treatments more precisely rather than relying only on the cancer's location.
Clinical trials continue to investigate new immunotherapies and combinations.
Research areas include:
Clinical-trial eligibility depends on cancer type, stage, previous treatment, biomarkers, and other medical factors.
Immunotherapy for cancer has become one of the most important developments in modern oncology. Rather than simply attacking rapidly dividing cells, many immunotherapies work by helping the immune system recognize cancer, strengthening immune activity, or removing biological signals that prevent immune cells from attacking tumors.
Checkpoint inhibitors targeting pathways such as PD-1, PD-L1, and CTLA-4 have become established treatments for numerous cancers. Cellular treatments such as CAR T-cell therapy have also transformed treatment for certain blood cancers. Other approaches, including monoclonal antibodies, therapeutic cancer vaccines, cytokine-based treatments, and newer immune therapies, continue to expand the field.