What Is Immunotherapy for Lung Cancer? How It Works
Immunotherapy for lung cancer works by helping a patient's own immune system recognize and attack cancer cells, most commonly by blocking checkpoint proteins like PD-1 and PD-L1 that cancer cells use to evade immune detection.
Cancer cells can produce proteins, including PD-L1, that bind to immune cells and effectively tell them not to attack โ a natural safety mechanism the immune system uses to avoid attacking the body's own healthy cells, which cancer cells exploit. Checkpoint inhibitor immunotherapy drugs block this signal, allowing immune cells to recognize and attack the cancer.
The first PD-1 checkpoint inhibitors were approved for lung cancer only in the mid-2010s, making the entire modern immunotherapy era in lung cancer younger than many people currently reading about it. Since then, immunotherapy has become a standard part of treatment for many NSCLC and some SCLC patients, often combined with chemotherapy.
PD-L1 expression testing โ measuring what percentage of tumor cells show the PD-L1 protein โ is one of the most widely used, though imperfect, predictors of how well a tumor might respond to checkpoint inhibitor immunotherapy.
Frequently Asked Questions
Does immunotherapy work for all lung cancer patients?
No โ response varies significantly, and biomarkers like PD-L1 expression and tumor mutational burden are used, imperfectly, to help predict likely benefit.
Is immunotherapy the same as chemotherapy?
No โ chemotherapy directly kills rapidly dividing cells, while immunotherapy works by re-enabling the immune system to recognize and attack cancer cells.