Prognostic value of post-radiation serum squamous cell carcinoma antigen and primary tumor regression for cervical squamous cell carcinoma

OBJECTIVE: In this study, we determined the prognostic values of magnetic resonance imaging (MRI)-based primary tumor regression and serum squamous cell carcinoma antigen (SSCC-Ag) levels 4 weeks after definitive radiotherapy (RT) in cervical squamous cell carcinoma (CSCC) patients. METHODS: This was a retrospective study involving 218 patients with histologically confirmed CSCC (stages IB-IVA). All the patients received definitive RT. Pre- and post-RT pelvic MRI and SSCC-Ag levels were measured. Locoregional control (LRC), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) were evaluated, and possible OS prognostic factors were analyzed. RESULTS: The median follow-up time was 25.57 (1.73-58.93) months. Thirty-six and 68 patients died and experienced recurrence, respectively, and the primary tumors of 130 (59.6%) and 88 (40.4%) patients exhibited complete response (CR) and non-CR, respectively. The 3-year OS, DFS, LRC, and DMFS rates were significantly higher in the CR than in the non-CR patients (85.2% vs. 67.9%, 78.9% vs. 39.0%, 93.4% vs. 63.8%, and 83.4% vs. 54.5%, respectively; p < 0.05). The 3-year OS, DFS, LRC, and DMFS rates were significantly lower in the patients with high post-RT SSCC-Ag levels than in those with low post-RT SSCC-Ag levels (38.0% vs. 83.9%, 21.2% vs. 66.3%, 73.0% vs. 84.9%, and 26.5% vs. 79.0%, respectively; p <0.05). Multivariate analyses indicated that SSCC-Ag levels were an independent OS predictor (HR: 5.749, 95% CI: 2.598-12.723, p < 0.001). CONCLUSION: Post-RT SSCC-Ag levels are OS independent prognostic factors in CSCC patients receiving RT. Timely and optimized treatment plans for CSCC patients after 4 weeks of RT are necessary when patients with persistent tumor and/or positive SSCC-Ag.