Lymph Node Status after Neoadjuvant Chemoradiation Therapy for Esophageal Cancer according to Radiation Field Coverage

Abstract

Background: To explore the effect of radiation on metastatic lymph nodes (LNs) after neoadjuvant chemo-radiation therapy (nCRT), we examined the metastatic features of LNs according to their inclusion in the ra-diation field. Methods: The patient group included 88 men and 2 women, with a mean age of 61.1±8.1 years, who underwent esophagectomy and lymphadenectomy after nCRT. Dissected LNs were compared in terms of clinical suspicion of metastasis, nodal station, and inclusion in the radiation field. Results: LN pos-itivity did not differ between LNs that were inside (in-field [IF]) and outside (out-field [OF]) of the radiation field (IF: 40 of 465 [9%], OF: 40 of 420 [10%]; p=0.313). In clinical N+ nodal stations, IF stations had a lower incidence of metastasis than OF stations (IF/cN+: 16 of 142 [11%], OF/cN+: 9/30 [30%]; p=0.010). However, in clinical N- nodal stations, pathological positivity was not affected by whether the nodal stations were included in the radiation field (IF/cN-: 24 of 323 [7%], OF/cN-: 31 of 390 [8%]; p=0.447). Conclusion: Radiation therapy for nCRT could downstage clinically suspected nodal metastasis. However, such therapy was ineffective when used to treat nodes that were not suspicious for metastasis. Because significant num-bers of residual metastases were identified irrespective of coverage by the radiation field, lymphadenectomy should be performed to ensure complete removal of residual nodal metastases after nCRT.

Keywords

• Esophageal neoplasms
• Esophageal surgery
• Lymph nodes
• Neoadjuvant therapy
• Radiotherapy