Stereotactic Ablative Radiotherapy for Early-Stage Lung Cancer.

The rising incidence of early-stage lung cancer, particularly in medically inoperable patients, is anticipated because of the implementation of early detection strategies and population aging in the United States and worldwide. This mandates the development of noninvasive curative treatment approaches for this disease. Stereotactic ablative radiotherapy (SABR) has recently emerged as a standard of care for early-stage lung cancer in medically inoperable patients who cannot safely tolerate surgical lobectomy, the established standard for operable patients. Further experience has demonstrated key principles with this highly conformal and dose-intensive radiation technique, including the need for sufficiently high biologically effective dose to achieve optimal local control, dose-fractionation modifications needed to treat centrally located tumors safely, and individualization of treatment based on tumor size, location, and other factors. SABR requires particular technical expertise including a nuanced understanding of dose prescription and calculation and appropriate management of tumor and organ motion. Progress continues as increasing experience with and data on SABR in selected cohorts of medically operable patients suggest comparable oncologic outcomes and a more favorable toxicity profile that challenges the historical standard of care for broader patient populations.