RongRong Zhou1, Ting Xu2, Quynh-Nhu Nguyen2, Ying Liu3, Ju Yang4, Ritsuko Komaki2, Daniel R Gomez2, Zhongxing Liao5. 1. Department of Radiation Oncology, Xiangya Hospital, Central South University, Changsha, Hunan, People's Republic of China; Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas. 2. Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas. 3. Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas; Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People's Republic of China. 4. Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas; The Comprehensive Cancer Center of Drum Tower Hospital, Medical School of Nanjing University and Clinical Cancer Institute of Nanjing University, Nanjing, Jiangsu, People's Republic of China. 5. Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas. Electronic address: zliao@mdanderson.org.
Abstract
PURPOSE: To identify predictors of local control and overall survival (OS) for patients with inoperable non-small cell lung cancer treated with concurrent chemoradiation therapy. METHODS AND MATERIALS: We identified 491 patients with newly diagnosed stage IIIA-IIIB non-small cell lung cancer who had received 60 to 74 Gy (with concurrent chemotherapy) from January 2005 through December 2013 and grouped them by radiation dose received: 60 to 63 Gy, 64 to 66 Gy, 67 to 70 Gy, or 71 to 74 Gy. Local progression (LP) was that appearing within the high-dose volume (planning target volume plus 1-cm margin). Times to events were calculated from the completion of radiation therapy. Potential predictors of LP and OS were analyzed with a Cox regression model. RESULTS: Rates of LP for all patients were 16.2% at 1 year, 26.2% at 2 years, 31.0% at 3 years, 32.9% at 4 years, and 32.9% at 5 years; corresponding OS rates were 85.3%, 61.2%, 44.5%, 37.0%, and 31.6%. Median OS time was 21 months (range, 2.9-99.9 months). In multivariate analysis, receipt of 67 to 70 Gy was associated with improved LP-free survival (LPFS) relative to 60 to 63 Gy (hazard ratio [HR] 1.83, 95% confidence interval [CI] 1.062-3.150, P=.030) or 64 to 66 Gy (HR 2.14, 95% CI 1.159-3.969, P=.015). Non-squamous histology (HR 0.23, 95% CI 0.114-0.478, P=.000), gross tumor volume (HR 1.00, 95% CI 1.000-1.003, P=.018) and induction chemotherapy (HR 1.86, 95% CI 1.239-2.778, P=.003) were independent predictors of LPFS. Local progression-free survival was the only independent predictor of OS (HR 2.71, 95% CI 1.331-5.512, P=.006). Incidence of grade ≥3 radiation pneumonitis was no different among dose groups (P=.307). CONCLUSIONS: Squamous histology, large tumor volumes, and receipt of induction chemotherapy all predicted worse LPFS. Doses of 67 to 70 Gy were associated with improved LP-free survival after chemoradiotherapy. The link between LP and reduced OS suggests that more effective local control strategies are warranted.
PURPOSE: To identify predictors of local control and overall survival (OS) for patients with inoperable non-small cell lung cancer treated with concurrent chemoradiation therapy. METHODS AND MATERIALS: We identified 491 patients with newly diagnosed stage IIIA-IIIB non-small cell lung cancer who had received 60 to 74 Gy (with concurrent chemotherapy) from January 2005 through December 2013 and grouped them by radiation dose received: 60 to 63 Gy, 64 to 66 Gy, 67 to 70 Gy, or 71 to 74 Gy. Local progression (LP) was that appearing within the high-dose volume (planning target volume plus 1-cm margin). Times to events were calculated from the completion of radiation therapy. Potential predictors of LP and OS were analyzed with a Cox regression model. RESULTS: Rates of LP for all patients were 16.2% at 1 year, 26.2% at 2 years, 31.0% at 3 years, 32.9% at 4 years, and 32.9% at 5 years; corresponding OS rates were 85.3%, 61.2%, 44.5%, 37.0%, and 31.6%. Median OS time was 21 months (range, 2.9-99.9 months). In multivariate analysis, receipt of 67 to 70 Gy was associated with improved LP-free survival (LPFS) relative to 60 to 63 Gy (hazard ratio [HR] 1.83, 95% confidence interval [CI] 1.062-3.150, P=.030) or 64 to 66 Gy (HR 2.14, 95% CI 1.159-3.969, P=.015). Non-squamous histology (HR 0.23, 95% CI 0.114-0.478, P=.000), gross tumor volume (HR 1.00, 95% CI 1.000-1.003, P=.018) and induction chemotherapy (HR 1.86, 95% CI 1.239-2.778, P=.003) were independent predictors of LPFS. Local progression-free survival was the only independent predictor of OS (HR 2.71, 95% CI 1.331-5.512, P=.006). Incidence of grade ≥3 radiation pneumonitis was no different among dose groups (P=.307). CONCLUSIONS: Squamous histology, large tumor volumes, and receipt of induction chemotherapy all predicted worse LPFS. Doses of 67 to 70 Gy were associated with improved LP-free survival after chemoradiotherapy. The link between LP and reduced OS suggests that more effective local control strategies are warranted.