Prognostic histological factors in patients with esophageal squamous cell carcinoma after preoperative chemoradiation followed by surgery

BACKGROUND: Pathological response is an important marker for tumor aggressiveness in patients with esophageal squamous cell carcinoma (ESCC) who receive preoperative chemoradiation followed by esophagectomy. We aim to evaluate the prognostic value of histological factors after trimodality treatments. METHODS: 91 patients who received preoperative chemoradiation followed by transthoracic esophagectomy between 2009 and 2014 were included. The pathological examination was reviewed. Overall survival and disease free survival were recorded. Survival analysis was performed using the Cox regression model, and the survival curves were compared by the log-rank test. RESULTS: Survival analysis showed lymphovascular invasion (LVI, hazard ratio [HR]: 2.009, p = 0.029), perineural invasion (PNI, HR: 2.226, p = 0.019), ypN stage (HR: 2.041, p = 0.019), extracapsular invasion (ECI, HR: 2.804, p = 0.003), and incomplete resection (HR: 1.897, p = 0.039) as unfavorable prognostic factors affecting overall survival (OS). Moreover, tumor regression grade (TRG, HR: 1.834, p = 0.038), LVI (HR: 1.975, p = 0.038), ECI (HR: 2.836, p = 0.003), and incomplete resection (HR: 2.254, p = 0.007) adversely affected disease-free survival (DFS). Prognostic classification based on poor primary tumor (TRG2/3, LVI(+), and PNI (+)), lymph node (ypN(+) and ECI(+)), and surgical (incomplete resection) factors significantly predicts OS (p = 0.013) and DFS (p = 0.017). However, the use of postoperative adjuvant therapy was not a significant prognostic factor even in medium- and high-risk ESCC patients who underwent trimodality treatments. CONCLUSIONS: Histological factors, including primary tumor, lymph node, and surgical factors has high prognostic value for predicting outcomes in ESCC patients receiving preoperative chemoradiation followed by surgery.