Immunotherapy

Immunotherapy is a type of cancer treatment that helps the immune system recognize and attack cancer cells more effectively. Cancer cells can use different mechanisms to evade immune detection, and some immunotherapies work by removing these immune “brakes” and restoring an antitumor immune response.

Immune checkpoint inhibitors are among the most widely used forms of immunotherapy for solid tumors. These drugs target pathways such as PD-1, PD-L1, and CTLA-4 and are used in cancers including lung cancer, melanoma, kidney cancer, esophageal cancer, and stomach cancer. Immunotherapy is also used for certain blood cancers, including Hodgkin lymphoma.

In a broader sense, cancer immunotherapy also includes treatments such as bispecific antibodies and CAR-T cell therapy, which are usually discussed as separate treatment categories.

Whether immunotherapy is appropriate depends on the cancer type, stage, previous treatments, and relevant biomarkers. Different cancers vary considerably in their sensitivity to immunotherapy, and these treatments are not appropriate for every patient.

For some solid tumors, biomarkers such as PD-L1 expression, microsatellite instability (MSI), and mismatch repair (MMR) status may help guide treatment decisions. Immunotherapy may be given alone or in combination with chemotherapy, targeted therapy, or another immunotherapy drug.

In some cancers, immunotherapy is used not only for advanced or metastatic disease but also before surgery as neoadjuvant therapy, after surgery as adjuvant therapy, or as part of treatment for locally advanced disease.

Immune checkpoint inhibitors are usually given by intravenous infusion, although other methods of administration are available for some drugs. The treatment schedule and duration depend on the cancer type, specific drug, treatment goal, and the patient's overall condition.

During treatment, imaging is used to assess changes in the cancer, while blood counts, liver and kidney function, thyroid function, and other laboratory tests may be monitored for treatment response and side effects.

Tumor response patterns after immunotherapy can sometimes differ from those seen with traditional chemotherapy, so treatment response is assessed using imaging, clinical symptoms, and other relevant findings.

Immunotherapy can sometimes cause the immune system to become overactive and attack healthy tissues, resulting in immune-related adverse events. Unlike many traditional chemotherapy side effects, these reactions can affect almost any organ and may occasionally develop even after treatment has ended.

Common immune-related side effects include rash, itching, diarrhea and colitis, thyroid problems, hepatitis, and pneumonitis. Less commonly, serious complications such as myocarditis, nephritis, or neurologic inflammation may occur.

Many immune-related adverse events can be controlled when recognized and treated promptly. More serious reactions may require immunotherapy to be paused or stopped and treatment with corticosteroids or other immunosuppressive medications. New or worsening symptoms such as persistent diarrhea, difficulty breathing, severe fatigue, or chest pain should be reported promptly to the healthcare team.