A narrative review of toxicity of chemoradiation and immunotherapy for unresectable, locally advanced non-small cell lung cancer

Despite declining smoking rates, lung cancer remains the second most common malignancy in the United States and the leading cause of cancer-related mortality. Non-small cell lung cancer (NSCLC) comprises roughly 85% of cases, and patients tend to present with advanced disease. Historically, concurrent chemoradiotherapy (CRT) has been the standard of care for stage III unresectable NSCLC but outcomes even with multimodal therapy have remained relatively poor. Efforts to improve outcomes through radiation dose escalation with conventional dose fractionation were unsuccessful with RTOG 0617, demonstrating significantly decreased overall survival (OS) with high dose radiation with respect to standard therapy. The recent PACIFIC trial established a new role for consolidative immune checkpoint blockade therapy after CRT using the programmed death ligand 1 (PD-L1) inhibitor durvalumab, by demonstrating significantly improved progression free survival and OS. Although promising, the addition of immunotherapy to multimodal therapy has generated debate regarding the most effective immune pathways to target, appropriate sequencing of therapy, most effective radiation techniques, and toxicity-related concerns. This review will highlight recent and ongoing trials in unresectable, locally advanced NSCLC that incorporate chemotherapy, radiation, and immunotherapy with an emphasis on analysis of treatment-related toxicities and implications for future study design.