targeted therapy

Targeted therapy is cancer treatment aimed at a specific molecular flaw that the tumor depends on, rather than at all fast-dividing cells the way traditional chemotherapy works. If chemotherapy is a broad weapon that hits the cancer but also healthy tissues, targeted therapy is more like a key cut to fit one particular lock — the abnormal protein keeping that tumor alive.

In lung cancer, these treatments are usually pills that block a single overactive driver. The best-known example is the EGFR inhibitor for tumors with an EGFR mutation, but there are others matched to alterations such as ALK, ROS1, BRAF, KRAS G12C, MET, and RET. Because each drug only helps tumors carrying its matching change, molecular testing of the tumor is required first to find out which, if any, target is present.

When a tumor has the right driver, targeted therapy can be remarkably effective and often more tolerable than chemotherapy, with patients sometimes returning to near-normal activity. This is the heart of what is called precision oncology: matching the treatment to the tumor's biology rather than to its location or appearance alone.

Two honest caveats. First, targeted drugs help only the subset of tumors with the matching alteration — they do nothing for tumors that lack it. Second, cancers usually evolve resistance over months to years, so therapy may need to be switched as new mutations emerge.