Who benefits from radiotherapy for gastric cancer? A meta-analysis.

Abstract

4093 Background: Randomized trials have demonstrated significant survival benefits with the use of adjuvant (including neoadjuvant) chemotherapy or chemoradiotherapy for gastric cancer. The importance of adjuvant radiotherapy (RT) remains unclear. Here we perform an up-to-date meta-analysis of randomized trials testing the use of radiotherapy for resectable gastric cancer. Methods: We searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials for randomized trials testing adjuvant RT for resectable gastric cancer. Hazard ratios describing the impact of adjuvant RT on overall survival (OS) and disease-free survival (DFS) were extracted directly from the original studies or calculated from survival curves. Pooled estimates were obtained using the inverse variance method. Subgroup analyses were performed to determine if the efficacy of RT varies with chemotherapy use, RT timing, geographic region, type of nodal dissection performed, and lymph node status. Results: Thirteen studies met all inclusion criteria and were used for this analysis. Adjuvant RT was associated with a significant improvement in both OS (HR=0.78, 95% CI: 0.70 to 0.86, p<0.001) and DFS (HR=0.71, 95% CI: 0.63 to 0.80, p<0.001). In the five studies that tested adjuvant chemoradiotherapy against adjuvant chemotherapy, similar effects were seen for OS (HR=0.83, 95% CI: 0.67 to 1.03, p=0.087) and DFS (HR=0.77, 95% CI: 0.91 to 0.65, p=0.002). Available data did not reveal any subgroup of patients that does not benefit from adjuvant RT. Conclusions: In randomized trials for resectable gastric cancer, adjuvant RT provides an approximately 20% improvement in both DFS and OS. Available data do not reveal a subgroup of patients that does not benefit from adjuvant RT. Further study is required to optimize the implementation of adjuvant RT for gastric cancer with regards to patient selection and integration with systemic therapy.