Background: Although squamous cell carcinoma antigen (SCC-Ag) is a tumor marker widely used to estimate the progression of esophageal SCC (ESCC), only a few studies have focused on the relationship between serum SCC-Ag levels and the therapeutic effect of neoadjuvant chemotherapy (NAC).
Objective: This study aimed to elucidate the clinical significance of pretherapeutic serum SCC-Ag levels in patients who underwent NAC followed by esophagectomy.
Methods: Data of 453 patients who underwent NAC followed by esophagectomy were collected from the esophageal cancer database of two high-volume Japanese centers. Serum SCC-Ag levels were measured prior to NAC, and the pathological therapeutic effect of NAC and patient survival were evaluated. Patients were classified according to the tertiles of the serum SCC-Ag value (low, middle, and high groups), and the outcomes among the groups were compared.
Results: The levels of serum SCC-Ag were significantly associated with tumor stage (p < 0.01). With regard to the pathological therapeutic effect, the levels of serum SCC-Ag were negatively correlated with the therapeutic effect (p = 0.02). Moreover, increased levels of serum SCC-Ag negatively influenced relapse-free survival (p < 0.01). Multivariate analyses revealed the 'high' group as the independent factor for both the unfavorable therapeutic effect (p = 0.01) and the increased risk of disease recurrence (p < 0.01) when compared with the 'low' group.
Conclusion: Elevated levels of pretherapeutic serum SCC-Ag are significantly associated with advanced tumor stage, poor response to NAC, and increased risk of disease recurrence.