Stereotactic body radiation therapy (SBRT) for lung cancer patients previously treated with conventional radiotherapy: a review.

Lung cancer continues to be one of the most prevalent malignancies worldwide and is the leading cause of death in both men and women. Presently, local control rates are quite poor. Improvements in imaging and radiation treatment delivery systems however have provided radiation oncologists with new tools to better target these tumors. Stereotactic body radiation therapy (SBRT) is one such technique that has shown efficacy as upfront treatment for lung cancer. In addition, more recent studies have demonstrated some effectiveness in recurrent tumors in prior irradiated fields as well. This review summarizes seven recent studies of re-irradiation with SBRT in patients with thoracic recurrences treated previously with conventionally fractionated radiation therapy. Combined, 140 patients were included. The median initial thoracic radiation doses ranged from 50-87.5 Gy and median re-irradiation dose ranged from 40-80 Gy. Local control rates varied from 65-92%. Re-irradiation was well tolerated with few grade 4 and 5 complications (observed in one study). Currently, based on these published reports, re-irradiation with SBRT appears feasible for in-field thoracic recurrences, though caution must be taken in all cases of retreatment.