Prognostic Impact of Serum SCC Antigen in the 566 Upfront Surgery Group of Esophageal Squamous Cell Carcinoma: A Multi-Institutional Study of the Japan Esophageal Society

Purpose: This study aimed to determine the clinicopathologic and prognostic significance of squamous cell carcinoma antigen (SCC-Ag) in patients with esophageal SCC who underwent radical surgery without neoadjuvant therapy. Methods: This study included 566 patients with primary esophageal SCC who underwent radical resection without neoadjuvant therapy at 15 Japanese hospitals between 2008 and 2016. The cutoff value of SCC-Ag was 1.5 ng/mL based on the receiver operating characteristic curves. Preoperative SCC-Ag and postoperative SCC-Ag were analyzed to evaluate clinicopathological and prognostic significance. Survival curves were compared between the SCC-Ag-positive group and the SCC-Ag-negative group. The prognostic impact of SCC-Ag was evaluated using univariate and multivariate analyses. Results: The preoperative SCC-Ag-positive rate was 23.5% (133/566). SCC-Ag-positive status was significantly associated with old age (p = 0.042), tumor depth (p <0.001), and tumor stages (p <0.001). The preoperative SCC-Ag-positive group had significantly poorer overall survival than the SCC-Ag-negative group (p = 0.030), but it was not an independent predictor of poor prognosis. Postoperative SCC-Ag-positive status was an independent risk factor for poor overall survival (p = 0.034). Conclusion: Both pre- and postoperative SCC-Ag-positive statuses were significantly associated with poor prognosis. Postoperative SCC-Ag-positive status was an independent risk factor for predicting overall survival.