Significance of elevated SCC-Ag level on tumor recurrence and patient survival in patients with squamous-cell carcinoma of uterine cervix following definitive chemoradiotherapy: a multi-institutional analysis

OBJECTIVE: There is no definitive guideline for the significance and cut-off value of squamous-cell carcinoma antigen (SCC-Ag) in cervical cancer. Thus, we analyzed the significance and optimal cut-off value of SCC-Ag for predicting tumor recurrence and patient survival in squamous-cell carcinoma of uterine cervix. METHODS: From January 2010 to October 2016, we enrolled 304 cervical cancer patients with squamous-cell carcinoma staging International Federation of Gynecology and Obstetrics (FIGO) Ib–IVa and treated with definitive chemoradiotherapy (CRT) followed by intra-cavitary radiotherapy (ICR). The cut-off value of SCC-Ag level for tumor recurrence was calculated using the receiver operating characteristic (ROC) curve. The recurrence-free survival (RFS) and overall survival (OS) were assessed using Kaplan-Meier method to estimate the significance of SCC-Ag level. RESULTS: The optimal cut-off value of SCC-Ag level for predicting tumor recurrence was calculated and set at 4.0 ng/mL in the ROC curve. After a median follow-up period of 36.5 months, the 3-year RFS (56.6% vs. 80.2%, p<0.001) and OS (72.1% vs. 86.8%, p=0.005) were significantly lower in SCC-Ag ≥4 ng/mL arm than in <4 ng/mL arm. The 3-year locoregional recurrence (17.6% vs. 7.0%, p=0.012), distant metastasis (20.4% vs. 6.9%, p=0.002), and para-aortic recurrence (9.4% vs. 2.1%, p=0.012) rates were significantly higher in SCC-Ag ≥4 ng/mL arm than in SCC-Ag <4 ng/mL arm. CONCLUSION: Pre-treatment SCC-Ag level higher than 4 ng/mL may be a useful predictor of tumor recurrence in patients with squamous-cell carcinoma of uterine cervix treated with definitive CRT and ICR.