Promising clinical outcome of stereotactic body radiation therapy for patients with inoperable Stage I/II non-small-cell lung cancer

Purpose: To evaluate the efficacy and toxicity of hypofractionated stereotactic body radiotherapy in patients with Stage I/II non-small-cell lung cancer. Methods and Materials: Forty-three patients with inoperable Stage I/II non-small-cell lung cancer underwent treatment prospectively using the stereotactic gamma-ray whole-body therapeutic system (body gamma-knife radiosurgery) with 30 rotary conical-surface Co⁶⁰ sources focused on the target volume. Low-speed computed tomography simulation was conducted, which was followed by three-dimensional conformal radiotherapy planning. A total dose of 50 Gy was delivered at 5 Gy/fraction to the 50% isodose line covering the planning target volume, whereas a total dose of 70 Gy was delivered at 7 Gy/fraction to the gross target volume. The median follow-up duration was 27 months. Results: Three to 6 months after treatment, the complete response rate for body-gamma knife radiosurgery was 63%, and the overall response rate was 95%. The 1-year, 2-year, and 3-year local control rates were all 95% in all patients. The 1-year, 2-year, and 3-year overall survival rates were 100%, 91%, and 91%, respectively, in patients with Stage I disease and 73%, 64%, and 64%, respectively, in those with Stage II disease. Only 2.3% (1/43) of the patients had Grade 3 pneumonitis. Conclusion: Our highly focused stereotactic body radiotherapy method resulted in promising local control and survival with minimal toxicity.