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.

Shengfa Su,Zhu Ma,Zhu Ma,Zhu Ma,Zhixu He,Tao Li,Jiancheng Li,Bing Lu,Yu Wang,Yu Wang,Yu Wang,Qingsong Li,Xiaohu Wang,Ming Chen,You Lu,Yinxiang Hu,Huiqin Li,Yuju Bai,Weiwei Ouyang,Weiwei Ouyang,Weiwei Ouyang

doi:10.1186/s12885-016-2952-3

Abstract

BackgroundThe 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.MethodsEligible 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.ResultsA 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 cm3, 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).ConclusionsRadiation 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.

Highlights

The role of radiation therapy in addition to chemotherapy has not been well established in nonoligometastatic Stage IV non-small cell lung cancer (NSCLC)
When the whole group was subdivided into those with oligometastases (χ2 = 6.150, P = 0.013) or non-oligometastases (χ2 = 8.257, P = 0.004), thoracic radiation dose ≥63 Gy remained a prognostic factor for better overall survival
Our findings suggest that non-oligometastatic NSCLC patients benefit from higher radiation doses (≥63 Gy) to the primary tumor based on effective systemic chemotherapy

Summary

Introduction

The role of radiation therapy in addition to chemotherapy has not been well established in nonoligometastatic Stage IV non-small cell lung cancer (NSCLC). 60% of patients who have been newly diagnosed with non-small cell lung cancer (NSCLC) have distant metastases [1]. Hellman et al [2] proposed a notion is that of oligometastases in 1995, oligometastases is the state in which the patient shows distant metastase are limited in number and locations. There are many other patients who have extensive and widespread metastases, this metastatic state might be called "non-oligometastases". There is increasing evidence showed that patients presenting with oligometastatic NSCLC could benefit from aggressive thoracic radiotherapy beyond palliative irradiation [6,7,8,9,10,11,12]. There was no consistent definition of oligometastases in these studies

Objectives

Methods

Results

Discussion

Conclusion