Stereotactic Radiotherapy by Indication Primary Lung Cancers

The standard of care for early-stage (node negative) non-small cell lung cancer has historically been surgical resection. However, many patients presenting with this diagnosis have comorbidities that preclude oncologic resection. In that regard, stereotactic body radiotherapy (SBRT) has emerged over the past 25 years as a curative radiation modality for the medically inoperable, early-stage lung cancer population. SBRT involves delivery of very high (ablative) doses of radiotherapy in 5 or fewer fractions while stringently minimizing dose to critical normal structures. It requires treatment platforms that account for respiratory motion and that provide very precise and reproducible means of achieving treatment setup accuracy while ensuring reliable verification at the time of delivery. A large number of retrospective and prospective studies published have established SBRT as the standard of care for inoperable patients because it has consistently demonstrated excellent local control with minimal toxicity, improved overall survival when compared to conventionally fractionated radiotherapy, and resulted in cancer-specific survivals similar to surgical patients. Since developing metastatic disease is the primary mode of failure for this population, studies are testing the role of systemic therapies in conjunction with SBRT. Ongoing trials are also seeking to establish its appropriateness for operable patients.