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To assess the effect of stereotactic body radiotherapy (SBRT) dose and tumor volume on outcomes in patients with recurrent, previously irradiated squamous cell carcinoma of the head and neck.A total of 96 patients with recurrent, previously irradiated squamous cell carcinoma of the head and neck were treated with SBRT using Cyberknife and Trilogy-intensity-modulated radiosurgery. Kaplan-Meier survival analyses were used to estimate locoregional control (LRC) and overall survival rates. Response was evaluated using positron emission tomography/computed tomography or computed tomography and detailed physical examination.The median follow-up for all patients was 14 months (2-39 months). The median dose of prior radiation was 68.4 Gy (32-170 Gy). Patients were divided into 4 SBRT dose groups: I (15-28 Gy/n = 29), II (30-36 Gy/n = 22), III (40 Gy/n = 18), and IV (44-50 Gy/n = 27). The median gross tumor volume (GTV) was 24.3(3) cm (2.5-162 cm). For GTV ≤25 cm(3) (n = 50), complete response rates were 27.8%/30%/45.5%/45.5%, and for GTV25 cm(3) (n = 46), complete response rates were 20%/25%/42.8%/50% for SBRT groups I-IV, respectively. The 1-/2-/3-year LRC rates for doses 40 to 50 Gy were 69.4%/57.8%/41.1%, respectively, whereas for 15 to 36 Gy, they were 51.9%/31.7%/15.9%, respectively (P = 0.02). The overall 1- and 2-year overall survival rates were 58.9% and 28.4%, respectively. Treatment was well tolerated with no grade 4/5 toxicities.Dose escalation up to 50 Gy in 5 fractions is feasible with SBRT for recurrent head and neck squamous cell carcinoma. Higher SBRT doses were associated with significantly higher LRC rates. Large tumor volume required higher SBRT doses to achieve optimal response rates compared with smaller tumor volume.

Objective Surgical resection is the standard of care for patients with stage I non–small cell lung cancer. For high-risk patients, however, stereotactic radiosurgery may offer an alternative. We report our initial experience with stereotactic radiosurgery for treatment of stage I non–small cell lung cancer by a team of thoracic surgeons and radiation oncologists. Methods Patients medically ineligible for operation were offered stereotactic radiosurgery. Thoracic surgeons evaluated all patients, placed fiducials, and performed treatment planning in collaboration with radiation oncologists. Median dose of 20 Gy to 80% isodose line was administered as single fraction (range 20–60 Gy,1–3 fractions). Initial response rate, progression, and survival were monitored. Results Twenty-one patients underwent stereotactic radiosurgery in 3 years. Fiducial placement resulted in pneumothorax requiring a pigtail catheter in 10 of 21 patients (47%). Disease showed initial response in 12 of 21 patients (57%), was stable in 5 (24%), progressed in 3 (14%), and was not evaluable in 1 (5%). Procedure-related mortality was zero. With mean 24-month follow-up, estimated 1-year survival probability was 81% (68% confidence interval 0.73–0.90). Median survival was 26.4 months (confidence interval 19.6 months–not reached). Local progression occurred in 9 patients (42%). Median time to local progression was 12.3 months (confidence interval 12 months–not reached). Conclusion Preliminary experience indicates that stereotactic radiosurgery (median dose 20 Gy) is safe in this high-risk group; however, it was associated with significant local progression. Further prospective studies with multiple fractions are needed to evaluate its efficacy in this population.