Stereotactic radiotherapy for non-small cell lung cancer: From concept to clinical reality. 2011 update

Only 60% of patients with early-stage non-small cell lung cancer (NSCLC), a priori bearing a favorable prognosis, undergo radical resection because of the very frequent co-morbidities occurring in smokers, precluding surgery to be safely performed. Stereotactic radiotherapy consists of the use of multiple radiation micro-beams, allowing high doses of radiation to be delivered to the tumour (ranging from 7.5 to 20 Gy per fraction) in a small number of fractions (one to eight on average). Several studies with long-term follow-up are now available, showing the effectiveness of stereotactic radiotherapy to control stage I/II non-small cell lung cancer in medically inoperable patients. Local control rates are consistently reported to be above 95% with a median survival of 34 to 45 months. Because of these excellent results, stereotactic radiation therapy is now being evaluated in operable patients in several randomized trials with a surgical arm. Ultimately, the efficacy of stereotactic radiotherapy in early-stage tumours leads to hypothesize that it may represent an opportunity for locally-advanced tumors. The specific toxicities of stereotactic radiotherapy mostly correspond to radiation-induced chest wall side effects, especially for peripheral tumours. The use of adapted fractionation schemes has made feasible the use of stereotactic radiotherapy to treat proximal tumours. Overall, from a technical concept to the availability of specific treatment devices and the publication of clinical results, stereotactic radiotherapy represents a model of implementation in thoracic oncology. (authors)