Background: Extranodal invasion (ENI) has been reported to be associated with a poor prognosis in several malignancies. However, previous studies have included perinodal fat tissue tumor deposits in their definitions of ENI. To investigate the precise nature of ENI in esophageal squamous cell carcinoma (ESCC), we excluded these tumor deposits from our definition of ENI and defined tumor cell invasion through the lymph node capsule and into the perinodal tissues as lymph node capsular invasion (LNCI). The aim of the current study was to elucidate the significance of LNCI in ESCC.
Methods: We investigated the associations between LNCI and other clinicopathologic features in 139 surgically resected ESCC. We also investigated the prognostic significance of LNCI in ESCC.
Results: LNCI was detected in 35 (25.2%) of 139 patients. The overall survival rate of the ESCC patients with LNCI was significantly lower than that of the ESCC patients with lymph node metastasis who were negative for LNCI. The survival difference between the patients with 1–3 lymph node metastases without LNCI and those with no lymph node metastasis was not significant. LNCI was significantly associated with distant organ recurrence. LNCI was also found to be an independent predictor of overall survival in addition to the number of lymph node metastases.
Conclusions: LNCI in ESCC patients is an indicator of distant organ recurrence and a worse prognosis. LNCI could be used as a candidate marker for designing more precise staging and therapeutic strategies for ESCC.