Single-Fraction Lung SBRT Outcomes for Tumors ≥ 3cm

For the 61 pts, median follow up interval was 12.2 months (m). Pt characteristics included: female (57.4%); median age 76.8 years (range 56.5-94.3); median KPS 80 (range 50-100); active smokers 11.5%; median body mass-index 25.8 (range 16.4-48.8). Tumor characteristics included: median diameter 3.3 cm (range 3.0-6.6) with tumor size cohorts (% of total) being: 3-3.9 cm (73.8%); 4-4.9 cm (21.3%); 5-6.6 cm (4.9%); median PET SUVmax 9.1 (range 1.7-41.5); 6.6% were oligometastatic and 3.3% oligoprogressive; 93.4% were biopsy-proven with adenocarcinoma being 45.9%; 49.2% abutted the chest wall. SF-SBRT dose was 34 Gy in 80.3% cases and 30 Gy in 19.7%. At analysis, toxicity of any grade/type was seen in 27.5% pts, with no > grade 3 cases; 6.6% of pts had grade 2 chest wall toxicity. Rates (in %) of local, lobar, nodal and distant failure were 1.7, 1.7, 13.1 and 21.3, respectively. There was no significant difference in failure by size cohort. Median OS was 33 m, with 1-year OS at 75%. When analyzed by cohort, OS significantly declined with increasing size (p = 0.0421) CONCLUSION: Local control and toxicity with SF-SBRT for tumors > 3cm is comparable to that seen with smaller tumors treated on randomized trials.