Recommendation for the definition of postoperative radiotherapy target volume based on a pooled analysis of patterns of failure after radical surgery among patients with thoracic esophageal squamous cell carcinoma

BACKGROUND: Elective use of radiation therapy to treat regionally involved lymph nodes (LNs) after radical surgery for esophageal squamous cell carcinoma (ESCC) is controversial. We studied metastasis patterns through a pooled analysis of published results to guide post-operative radiotherapy (PORT) target designation. METHODS: We searched the MEDLINE database for literature published from May 1977 to March 2018, and found 14 relevant original studies that included 2738 patients with thoracic ESCC. We calculated probabilities of recurrence and metastasis in local (including anastomoses and tumor bed), LNs and distal areas. RESULTS: Recurrence rates were 1.88% for local, 13.18% for distal, and 22.16% for LNs. Within LNs, recurrence rates were cervical/supraclavicular: 37.69%, upper mediastinal: 44.30%, middle mediastinal: 21.81%, lower mediastinal: 2.57%, abdominal paraaortic: 25% and upper abdominal: 9.56%. Whereas cervical/supraclavicular and upper mediastinal LNs had the highest recurrence rates, abdominal LNs also had high recurrence rates in patients with lower thoracic ESCC. CONCLUSIONS: PORT volume should include the cervical/supraclavicular and upper mediastinal LNs for all thoracic ESCC, and abdominal paraaortic LNs for lower thoracic ESCC. Anastomoses and tumor beds should not be included in the PORT volume if they are not adjacent to the PORT-LN regions. Upper abdominal LNs might not necessarily be included in the PORT volume for thoracic ESCC. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13014-018-1199-3) contains supplementary material, which is available to authorized users.