Pattern of lymph node metastases and its implication in radiotherapeutic clinical target volume in patients with small cell carcinoma of the esophagus: A multicenter retrospective trial from China (CHiSCEC)

Abstract

Abstract Purpose: In order to study the pattern of LNM after esophagectomy of small cell carcinoma of the esophagus (SCCE) and clarify the clinical target volume (CTV) delineation of definite radiotherapy for SCCE. Methods: From January 2007 to December 2020, 286 patients with SCCE who had undergone esophagectomy and lymphadenectomy were retrospectively examined from 14 cancer centers in China. The distribution of lymph node metastases (LNM) were evaluated and the clinicopathologic factors related to lymph node metastasis were analyzed using logistic regression analysis. Results: 177 patients (61.9%) occurred LNM in the 286 patients, and the incidence of LNM was 12.3%(597/4850).Those sites with an LNR rate higher than 10% in upper thoracic SCCE were as follows: No.105, No. 106recR and No.106recL. Those with middle thoracic SCCE were as follows: No.107, No.108 and abdominal No. 7. Lastly, individuals with lower thoracic SCCE were as follows: No.107, No. 110, abdominal No. 2, and abdominal No. 7. T stage, age and the length of tumor were the statistically significant risk factors of LNM of SCCE (P < 0.05).A nodal clinical target volume ༈CTVn) countoring recommendation were offered. Conclusions: LNM pattern of SCCE varies depending upon the primary tumor location. The irradiation field must be designed according to the primary tumor location. The rate of lymph node metastasis of the SCCE increased with the T stage and the length of tumor. These factors and the correlated lymphatic drainage regions should be considered when designing the CTV for Selective regional irradiation of SCCE.