EGFR mutations and ALK rearrangements are present in roughly 20 to 30 percent of non-small cell lung cancers, and they are the lung cancers that respond most spectacularly to oral targeted tyrosine kinase inhibitors. Osimertinib for EGFR-mutated disease and alectinib for ALK-rearranged disease can produce deep responses where scans show near-complete disappearance of measurable disease, and patients feel well, maintain quality of life, and live productively on a daily oral tablet. The problem is resistance. Cancer cells under the pressure of a targeted therapy eventually evolve mechanisms to escape it, and progression occurs. But this progression is often not uniform. In many patients, the targeted therapy continues to suppress 99 percent of the disease, but one spot in the liver, one bone metastasis, or one brain lesion finds a way around the drug and starts to grow. This is called oligoprogression, and it is a clinical situation that SBRT was made for. Instead of taking the patient off a well-tolerated, highly effective targeted therapy and replacing it with a new regimen that may be less effective and more toxic, I use SBRT to ablate the single site of progression while keeping the patient on the TKI that continues to control disease everywhere else. In this way, we are extending the effective life of a first-line or second-line targeted therapy by months or sometimes years. At NiSH Clinic, Jayanagar, Bengaluru, I assess every EGFR and ALK lung cancer patient for oligoprogression at each restaging scan, because identifying it early allows us to act on it with precision before systemic progression becomes widespread.
Written by Dr. Swaroop Revannasiddaiah, MBBS, MD (Radiotherapy and Clinical Oncology), DM (Medical Oncology), MRCP (Medical Oncology, Royal College of Physicians, UK), ESMO Certified, Thoracic Oncology Certification (University of Michigan, USA), Senior Consultant Medical Oncologist, NiSH Clinic, 48, 7th B Main Road, near Vinayaka Temple, 4th Block, Jayanagar, Bengaluru, Karnataka 560011. Phone: +91 9731174360. Clinic: Monday to Thursday, 3:00 PM to 4:00 PM.
