Clinical Significance of Serum Squamous Cell Carcinoma Antigen for Patients with Recurrent Esophageal Squamous Cell Carcinoma

Background Squamous cell carcinoma antigen (SCC-Ag) is a widely used tumor marker of SCC. However, the clinical significance of serum SCC-Ag levels in recurrent esophageal SCC (ESCC) remains unclear. This study aimed to investigate the clinical relevance of serum SCC-Ag levels in patients with recurrent ESCC after surgery. Methods This study retrospectively analyzed 208 patients who experienced recurrence after curative resection for ESCC. Serum SCC-Ag levels at the time of recurrence were collected from the patients' records. The patients were classified into tertiles based on the serum SCC-Ag values (low, middle, and high), and the clinical characteristics and outcomes were compared among the groups. Results Significant differences in sex (p = 0.001), pathologic T (p = 0.034), and N stages of primary cancer (p = 0.015) were observed among the groups. Although the recurrence patterns did not differ significantly, a high SCC-Ag was significantly associated with multiple recurrences (p = 0.019). The high-SCC-Ag group patients demonstrated a shorter time to recurrence than the other groups (p = 0.044). The SCC-Ag levels were significantly associated with overall survival after recurrence (p = 0.036). Multivariate analysis showed that serum SCC-Ag value at recurrence was an independent poor prognosticator (p = 0.031). Conclusion Elevated serum SCC-Ag levels at recurrence were significantly associated with a reduced time to recurrence, multiple recurrences, and a poor prognosis after recurrence. An alternative to the current standard treatment is required to improve the outcome for patients with high serum SCC-Ag levels at recurrence.