Neoadjuvant chemoradiotherapy or chemotherapy? A comprehensive systematic review and meta-analysis of the options for neoadjuvant therapy for treating oesophageal cancer.

Neoadjuvant therapy followed by surgery is a standard treatment for locally advanced oesophageal cancer. However, the roles of neoadjuvant chemoradiotherapy and chemotherapy in treating oesophageal cancer remain controversial. In this comprehensive meta-analysis, we examine the efficacy of adding radiotherapy to neoadjuvant chemotherapy for treating oesophageal cancer as reported in qualified randomized controlled trials (RCTs). We conducted a systematic literature search using PubMed, Embase, Cochrane Library databases, Google Scholar and the American Society of Clinical Oncology database to identify relevant studies up to 31 March 2016. Data including the pathological complete response rate, R0 resection rate and 3-year survival rate were extracted and analysed. Five qualified RCTs were included with a total of 709 patients. Meta-analysis showed that neoadjuvant chemoradiotherapy significantly increases the rates of pathological complete response and R0 resection in patients with oesophageal adenocarcinoma or squamous cell carcinoma (SCC). However, we found a significantly increased 3-year survival rate only in oesophageal SCC patients treated with neoadjuvant chemoradiotherapy compared with neoadjuvant chemotherapy (56.8 and 42.8%, respectively); relative risk (RR): 1.31 [95% confidence interval (CI) 1.10-1.58, P = 0.003]. In oesophageal adenocarcinoma patients, no significant survival benefit of neoadjuvant chemoradiotherapy was found compared with neoadjuvant chemotherapy alone (46.3 and 41.0%, respectively; RR: 1.13, 95% CI 0.88-1.45, P = 0.34). Our meta-analysis adds to the evidence showing that neoadjuvant chemoradiotherapy should be the standard preoperative treatment strategy for locally advanced oesophageal SCC. For oesophageal adenocarcinoma, neoadjuvant chemotherapy alone may be the best preoperative treatment strategy to avoid the risk of adverse effects of radiotherapy.