Advances in stereotactic body radiation therapy for early stage non-small cell lung cancer

Abstract

: Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related mortality in the United States, but as lung cancer screening expands to include younger patients with shorter smoking histories, an increasing number of cases are detected at early, more treatable stages. Stereotactic body radiation therapy (SBRT) has emerged as an effective, non-invasive treatment option for patients with medically inoperable NSCLC. Over the past decade, several retrospective and prospective studies have shown SBRT to achieve superior local control and overall survival compared to conventionally fractionated radiation therapy (CFRT). Advances in tumor targeting and radiation delivery have reduced treatment times while delivering higher doses of radiation to the tumor. SBRT is generally well-tolerated and the risk of grade 3 or greater toxicity is low with dose constraints in place to monitor and limit radiation delivered to surrounding normal tissues. Approaches to dose and fractionation vary depending on the tumor location relative to critical mediastinal structures, as toxicity profiles differ greatly among peripheral, central, and ultra-central tumors. While surgery remains the standard of care for operable patients and tumors, clinical trials are ongoing to compare SBRT with lobar and sub-lobar resection. Further studies combining SBRT with anti-PD-L1 and anti-PD-1 immunotherapy agents and radiosensitizing agents are in progress.