Identification of Optimal Parameters for Assessing Lymph Node Status of Patients with Esophageal Squamous Cell Carcinoma After Neoadjuvant Chemoradiotherapy

Background This study aimed to compare the prognostic discrimination power of pretreatment pathologic N stage (prepN), lymph node tumor regression grade (LNTRG), and posttreatment pathologic N (ypN) category for esophageal squamous cell carcinoma (ESCC) patients who received neoadjuvant chemoradiotherapy (nCRT) plus surgery.Methods The study reviewed 187 ESCC patients from two medical centers who underwent nCRT plus surgery. Pathologic LNTRG was defined by the proportion of viable tumor area within the tumor bed in lymph nodes (LNs). An average LNTRG then was calculated by averaging the tumor regression grade (TRG) score of all resected LNs. Lymph nodes containing regression changes or vital tumor cells were used for interpretation of the prepN stage, which reflects the estimated number of originally involved LNs.Results The ypN, prepN, and LNTRG categories had significant prognostic stratification power (p < 0.001, log-rank test). Multivariable cox regression showed that all three categories were independent prognostic factors of disease-free survival (DFS) (p < 0.05). The LNTRG category showed a better prognostic value for DFS prediction than the ypN and prepN categories (Akaike information criterion [AIC]: LNTRG [933.69], ypN [937.56], prepN [937.45]). Additionally, the superior predictive capacity of the LNTRG category was demonstrated by decision curve analysis. Similar results were discovered for patients with remaining diseased LNs.Conclusions The three staging categories had prognostic relevance for DFS, with the LNTRG category seeming to have better prognostic indication power. Comprehensive consideration of the ypN status, prepN status, and LN regression may allow for better prognostic stratification of patients.