Salvage radiotherapy for postoperative locoregional failure in esophageal cancer: a systematic review and meta-analysis

Locoregional recurrences following surgery for esophageal cancers represent a significant clinical problem with no standard recommendations for management. We conducted this systematic review and meta-analysis with the objective of studying safety and efficacy of salvage radiotherapy in this setting. All prospective and retrospective cohort studies, which studied patients who developed locoregional recurrence following initial radical surgery for esophageal cancer and subsequently received salvage radiation therapy (RT)/chemoradiation with all relevant information regarding survival outcome and toxicity available, were included. The quality of eligible individual studies was assessed using the Newcastle-Ottawa Scale score for risk of bias. R package MetaSurv was used to obtain a summary survival curve from survival probabilities and numbers of at-risk patients collected at various time points and to test the overall heterogeneity using the I-2 statistic. Thirty studies (27 retrospective, 3 prospective) published from 1995 to 2020 with 1553 patients were included. The median interval between surgery and disease recurrence was 12.5 months. The median radiation dose used was 60 Gy and 57% received concurrent chemotherapy. The overall incidence of acute grade 3/4 mucositis and dermatitis were 8 and 4%, respectively; grade 3/4 acute pneumonitis was reported in 5%. The overall median follow-up of all studies included was 27 months. The 1-, 2- and 3-year overall survival (OS) probabilities were 67.9, 35.9 and 30.6%, respectively. Factors which predicted better survival on multivariate analysis were good PS, lower group stage, node negativity at index surgery, longer disease-free interval, nodal recurrence (as compared to anastomotic site recurrence), smaller disease volume, single site of recurrence, RT dose >50 Gy, conformal RT, use of concomitant chemotherapy and good radiological response after radiotherapy. Salvage radiotherapy with or without concomitant chemotherapy for locoregional recurrences after surgery for esophageal cancer is safe and effective. Modern radiotherapy techniques may improve outcomes and reduce treatment-related morbidity.