Might radiation therapy in addition to chemotherapy improve overall survival of patients with non-oligometastatic Stage IV non-small cell lung cancer?: Secondary analysis of two prospective studies

Might radiation therapy in addition to chemotherapy improve overall survival of patients with non-oligometastatic Stage IV non-small cell lung cancer?: Secondary analysis of two prospective studies

BMC Cancer, November 2016

27871270

ShengFa Su, YinXiang Hu, WeiWei Ouyang, Zhu Ma, QingSong Li, HuiQin Li, Yu Wang, XiaoHu Wang, Tao Li, JianCheng Li, Ming Chen, You Lu, YuJu Bai, ZhiXu He, Bing Lu

The role of radiation therapy in addition to chemotherapy has not been well established in non-oligometastatic Stage IV non-small cell lung cancer (NSCLC). We aimed to investigate overall survival (OS) of non-oligometastatic Stage IV NSCLC treated with chemotherapy with concurrent radiation to the primary tumor. Eligible patients were screened from two prospective studies. Oligometastatic and non-oligometastatic NSCLC were defined as having < 5 and ≥5 metastatic lesions, respectively. Prognostic factors for OS were identified by using univariate and multivariate analysis. Landmark analysis and propensity-score matching (PSM) were each performed to further adjust for confounding. A total of 274 patients were identified as the study cohort: 183 had non-oligometastatic disease. For all 274 patients, those who received a radiation dose ≥63 Gy to the primary tumor and had oligometastatic disease had better OS (P < 0.001 and P = 0.017, respectively). When patients were subdivided into those with oligometastatic or non-oligometastatic disease, a radiation dose ≥ 63 Gy remained a significant prognostic factor for better OS. For non-oligometastatic patients, multivariate analysis showed that receiving ≥63 Gy radiation, having a GTV <146 cm(3), having response to chemotherapy, and having stable or increased post-treatment KPS independently predicted better OS (P = 0.018, P = 0.014, P = 0.014, and P = 0.001). After PSM in non-oligometastatic patients, a higher radiation dose (≥63 Gy) remained to be correlated with better OS. By landmark analysis, aggressive radiation (≥63 Gy) remained to be correlated with better OS in Pre-PSM cohort (P = 0.005) and Post-PSM cohort (P = 0.004). Radiation dose, primary tumor volume, response to chemotherapy and KPS after treatment are associated with OS in patients with non-oligometastatic disease; on basis of effective system chemotherapy, aggressive thoracic radiotherapy may prolong OS.