Clinicopathological Significance of Pathologic Complete Lymph Node Regression After Neoadjuvant Chemoradiotherapy in Esophageal Squamous Cell Carcinoma.

Abstract

Pathologic complete lymph node regression (LNR), where the lymph nodes show evidence of neoadjuvant treatment effect but have no viable residual tumor cells, is sometimes observed following neoadjuvant treatments and has been shown to be prognostic; conflicting results exist in the current literature. Patients who received neoadjuvant chemoradiotherapy (nCRT) followed by esophagectomy for squamous carcinoma (ESCC) were retrospectively reviewed and classified according to their LNR score; 0: N(-) with no evidence of tumor involvement or regression; 1: N(-) with evidence of complete regression; 2: N(+) with < 50% viable tumor; and 3: N(+) with > 50% viable tumor. In total, 136 patients, comprising 73, 25, 16, and 22 patients with LNR scores of 0, 1, 2, or 3, respectively, were included. Pathologic complete LNR (LNR1) was significantly associated with lower risks of lymphovascular invasion (0%, p<0.001) and perineural invasion (4%, p=0.038), and a higher rate of pathologic complete response in the primary tumor (76%, p<0.001). The 5-year overall survival rates were 42.1%, 52.8%, and 8.0% in patients with an LNR score of 0, 1, and 2/3, respectively (p<0.001). There was no significant difference between patients with LNR scores of 0 and 1 in overall survival (p=0.454), disease-free survival (p=0.501), and cumulative incidence of recurrences (hazard ratio 0.84, 95% confidence interval 0.432-1.623, p=0.601). Pathologic complete LNR could be an indicator of nCRT sensitivity and can be regarded as a good prognostic factor in patients with ESCC. In the survival curve analysis that included patients with lymph node regression (LNR) scores of 0 (blue), 1 (red), and 2/3 (green), we found that patients with pathologic complete LNR (LNR 1), which suggests prior positive nodal involvement, had similar outcomes as those without evidence of prior tumor involvement in lymph node (LNR0).