Stereotactic ablative body radiotherapy (SABR): an alternative to surgery in stage I-II non-small-cell cancer of the lung?

For decades, surgery was considered to be the only standard therapy for early-stage non-small cell lung cancer (NSCLC). However stereotactic ablative body radiotherapy (SABR) has been used in a growing number of patients and institutions since the early 2000's. Initially this technique was intended mainly for patients who were deemed to be medically inoperable due to co-morbidities or who refused surgery, but more recently it has been applied to operable patients as well. Strict criteria for treatment planning, the use of high-technology equipment and the appropriate selection of dose based on tumor size and location are of paramount importance for a proper application of SABR. Under these conditions, SABR offers high control rates with a moderate risk of severe toxicity, quite comparable to those of modern surgery. This article reviews the basic principles of SABR, its practical aspects, the definition of biologically equivalent doses, the results in terms of tumor control, survival and toxicity and an attempt will be made to compare the results of SABR with those of surgery.