Yuichiro Tsurugai1, Takuyo Kozuka2, Naoki Ishizuka3, Masahiko Oguchi2. 1. Radiation Oncology Department, Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Tokyo, Japan. Electronic address: yuichiro.tsurugai@jfcr.or.jp. 2. Radiation Oncology Department, Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Tokyo, Japan. 3. Clinical Trial Department, Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Tokyo, Japan.
Abstract
PURPOSE: We investigated whether the ratio of the maximum diameter of consolidation to the maximum tumor diameter (consolidation/tumor ratio, CTR) predicted the outcomes of patients who received stereotactic body radiotherapy (SBRT) for non-small-cell lung cancer (NSCLC). METHODS AND MATERIALS: Between 2005 and 2014, 237 patients with stage I NSCLC were treated with SBRT, receiving 48 Gy in 4 fractions. Of these patients, those who received pretreatment thin section computed tomography were selected for this analysis. The relationship between the CTR and outcomes (local control [LC], disease-free survival [DFS], and overall survival [OS]) was analyzed. RESULTS: One hundred and fifty-five patients were eligible. The median follow-up time was 34.7 months (range, 1.2-109.8). In the CTR<0.5, CTR 0.5-<1, and CTR=1 groups, 0, 2, and 12 patients experienced local recurrences, respectively. Three-year DFS and OS rates were 96.7% and 87.5% in the CTR<0.5 group, 85.1% and 81.1% in the CTR 0.5-<1 group, and 63.3% and 70.1% in the CTR=1 group, respectively. In multivariate analysis, CTR was the only significant predictor of DFS (P<0.001). CONCLUSION: The CTR effectively predicts DFS after SBRT in NSCLC patients.
PURPOSE: We investigated whether the ratio of the maximum diameter of consolidation to the maximum tumor diameter (consolidation/tumor ratio, CTR) predicted the outcomes of patients who received stereotactic body radiotherapy (SBRT) for non-small-cell lung cancer (NSCLC). METHODS AND MATERIALS: Between 2005 and 2014, 237 patients with stage I NSCLC were treated with SBRT, receiving 48 Gy in 4 fractions. Of these patients, those who received pretreatment thin section computed tomography were selected for this analysis. The relationship between the CTR and outcomes (local control [LC], disease-free survival [DFS], and overall survival [OS]) was analyzed. RESULTS: One hundred and fifty-five patients were eligible. The median follow-up time was 34.7 months (range, 1.2-109.8). In the CTR<0.5, CTR 0.5-<1, and CTR=1 groups, 0, 2, and 12 patients experienced local recurrences, respectively. Three-year DFS and OS rates were 96.7% and 87.5% in the CTR<0.5 group, 85.1% and 81.1% in the CTR 0.5-<1 group, and 63.3% and 70.1% in the CTR=1 group, respectively. In multivariate analysis, CTR was the only significant predictor of DFS (P<0.001). CONCLUSION: The CTR effectively predicts DFS after SBRT in NSCLCpatients.