Hypofractionated Stereotactic Radiotherapy for Primary and Secondary Intrapulmonary Tumors: First Results of a Phase I/II Study

PURPOSE: To evaluate the feasibility, efficacy, and side effects of dose escalation in hypofractionated stereotactic radiotherapy (hfSRT) for intrapulmonary tumors with the Novalis™ system (BrainLAB AG, Heimstetten, Germany). PATIENTS AND METHODS: From 07/2003 to 01/2005, 21 patients/39 tumors were treated with 5 × 7 Gy (n = 21; total dose 35 Gy) or 5 × 8 Gy (n = 18; total dose 40 Gy). There were three cases of primary lung cancer, the remainder were metastases. Median gross tumor volume (GTV) and planning target volume (PTV) were 2.89 cm(3) (range, 0.15–67.94 cm(3)) and 25.75 cm(3) (range, 7.18–124.04 cm(3)), respectively. RESULTS: Rates of complete remission, partial remission, no change, and progressive disease were 51%, 33%, 3%, and 13%, respectively. No grade 4 toxicity occurred, nearly all patients had grade 1 initially. One grade 3 toxicity, i.e., dyspnea, was documented for a period of 6 months after therapy. Radiosurgery quality assurance guidelines could be met. CONCLUSION: hfSRT of primary and secondary lung tumors using a schedule of five fractions at 7–8 Gy each was well tolerated. Further dose escalation is planned.