Posttreatment Squamous Cell Carcinoma Antigen in Predicting Treatment Failure for Patients with Cervical Squamous Cell Carcinoma Treated with Concurrent Chemoradiotherapy

Abstract

To analyze the association between posttreatment squamous cell carcinoma (SCC) antigen and treatment failure for patients with cervical SCC and treated with concurrent chemoradiotherapy (CCRT). We reviewed patients with cervical SCC and treated with definitive CCRT between June 2012 and May 2015 in our institute. A dose of 50.4Gy in 28 fractions was delivered to the pelvic with intensity modulated radiation therapy. With high-dose-rate brachytherapy, 30-36Gy in 5-7 fractions was prescribed to point A. The first line regimen of concurrent chemotherapy was cisplatin weekly. Posttreatment SCC antigen level was checked at 20 to 60 days after the completion of CCRT. A receiver operating characteristic (ROC) curve was performed to analyze the cutoff point of pretreatment and posttreatment SCC Ag in predicting treatment failure. Log-rank test and Cox’s proportional hazard model were used to identify whether pretreatment and posttreatment SCC Ag was significant in predicting disease-free survival (DFS). A total of 559 patients were included in this study. With ROC curve, the optimal cut-off points of pretreatment and posttreatment SCC antigen level were 8.6ng/ml (sensitivity 54.2%, specificity 65.8%) and 1.8 ng/ml (sensitivity 27.1%, specificity 96.6%). Posttreatment SCC antigen level ≥ 1.8ng/ml was observed in 47 patients. Multivariate analysis showed that posttreatment SCC Ag (hazard ratio 5.10, 95% confidence interval 3.31-7.88, p<0.001) was an independent prognostic factor of DFS. However, pretreatment SCC Ag was not significant in predicting DFS. The 3-year overall survival, DFS, local control and distant control rates of patients with posttreatment SCC antigen <1.8 ng/ml and ≥ 1.8 ng/ml were 90.7% and 46.4% (p<0.001), 84.8% and 31.9% (p<0.001), 81.4% and 69.5% (p<0.001), 90.4% and 54.1% (p<0.001), respectively. Cervical SCC patients with posttreatment SCC antigen ≥ 1.8ng/ml experienced high risk of treatment failure and poor survival. Consolidation therapy or extensive follow-up should be considered for these patients.