What is the optimal radiation dose for non-operable esophageal cancer? Dissecting the evidence in a meta-analysis

// Yong Chen 1, * , Hui-Ping Zhu 2, 3, * , Tao Wang 1, * , Chang-Jiang Sun 1 , Xiao-Lin Ge 2 , Ling-Feng Min 4 , Xian-Wen Zhang 1 , Qing-Qing Jia 1 , Jie Yu 1 , Jian-Qi Yang 1 , Heike Allgayer 5 , Mohammed L. Abba 5 , Xi-Zhi Zhang 1 and Xin-Chen Sun 2 1 Department of Medical Oncology, Northern Jiangsu People's Hospital, Clinical Medical College of Yangzhou University, Yangzhou, Jiangsu, China 2 Department of Radiotherapy, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China 3 Department of Medical Oncology, Zhangjiagang First People's Hospital, Zhangjiagang, Jiangsu, China 4 Department of Respiratory Medicine, Northern Jiangsu People's Hospital, Clinical Medical College of Yangzhou University, Yangzhou, Jiangsu, China 5 Department of Experimental Surgery-Cancer Metastasis, Medical Faculty Mannheim, University of Heidelberg, Germany and Centre for Biomedicine and Medical Technology, Medical Faculty Mannheim, University of Heidelberg, Germany * These authors contributed equally to this work Correspondence to: Xin-Chen Sun, email: sunxinchen2012@163.com Mohammed L. Abba, email: Mohammed.Abba@medma.uni-heidelberg.de Xi-Zhi Zhang, email: zhangxizhi@medmail.com.cn Keywords: esophageal cancer, radiation dose, meta-analysis, chemoradiotherapy, survival benefit Received: January 25, 2017      Accepted: June 05, 2017      Published: June 28, 2017 ABSTRACT The standard radiation dose 50.4 Gy with concurrent chemotherapy for localized inoperable esophageal cancer as supported by INT-0123 trail is now being challenged since a radiation dose above 50 Gy has been successfully administered with an observable dose–response relationship and insignificant untoward effects. Therefore, to ascertain the treatment benefits of different radiation doses, we performed a meta-analysis with 18 relative publications. According to our findings, a dose between 50 and 70 Gy appears optimal and patients who received ≥ 60 Gy radiation had a significantly better prognosis (pooled HR = 0.78, P = 0.004) as compared with 50.4/51 Gy) radiation when compared with those treated with low dose (≤ 50.4/51 Gy) radiation (pooled OR = 0.71, P = 0.06). Patients that received ≥ 60 Gy radiation had better locoregional control (OR = 0.29, P = 0.001), and for distant metastasis control, neither the > 50.4 Gy nor the ≥ 60 Gy treated group had any treatment benefit as compared to the groups that received ≤ 50.4 Gy and < 60 Gy group respectively. Taken together, a dose range of 50 to 70 Gy radiation with CCRT is recommended for non-operable EC patients. A dose of ≥ 60 Gy appears to be better in improving overall survival and locoregional control, especially in Asian countries, while the benefit of ≥ 60 Gy radiation in Western countries still remains controversial.