Correlation between Tumor Regression Grade and Clinicopathological Parameters in Patients with Squamous Cell Carcinoma of the Esophagus Who Received Neoadjuvant Chemoradiotherapy

The aim of this study was 2-fold: first, to assess the prognostic significance on overall survival (OS) of the 3-point tumor regression grade (TRG) in patients with esophageal squamous cell carcinoma (ESCC) who received neoadjuvant chemoradiotherapy (nCRT); second, to investigate the associations of TRG with the clinicopathological characteristics of the study patients. A total of 357 ESCC patients were retrospectively enrolled. The 3-point TRG was determined by assessing the percentage of viable residual tumor cells (VRTC) in the resected specimens as follows: TRG 1, 0% VRTC; TRG 2, 1% to 50% VRTC; and TRG 3, >50% VRTC. A TRG of 1, 2, and 3 was found in 32.2%, 38.9%, and 28.9% of the specimens, respectively. High TRG values were significantly associated with advanced pretreatment clinical stage, longer tumor length, and higher posttreatment tumor depth of invasion (yT), the presence of lymph node metastases (LNM), and lymphovascular invasion. We observed a stepwise decrease in 5-year OS rates with increasing TRG, as follows: 51% for patients with a TRG of 1, 28% for patients with a TRG of 2, and 22% for patients with a TRG of 3 (P<0.001). TRG and LNM were independent predictors of OS in multivariate analysis. Notably, the prognostic impact of TRG on OS was greater in patients without LNM (P<0.001) and ypT3 disease (P=0.021). TRG is independently associated with OS in ESCC patients treated with nCRT. The interrelationships between TRG, LNM, and depth of tumor invasion may improve the prognostic stratification in esophageal cancer.