Tumor marker screening may be useful to evaluate tumor response and detect tumor recurrence. However, usefulness and cut-off value of squamous-cell carcinoma antigen (SCC-Ag) for recurrence and survival has not yet established in cervical cancer.
From January 2010 to October 2016, 304 patients with cervical squamous-cell carcinomas with FIGO stage IB-IVA who underwent curative chemoradiotherapy followed by brachytherapy at four institutions were included in this study. Serum SCC-Ag level was measured before treatment, re-measured after completion of treatment, and again at the time of relapse during follow-up. SCC-Ag levels at each measurement point were analyzed using receiver operating characteristic (ROC) curve. Their associations with recurrence-free survival (RFS) and overall survival (OS) were analyzed.
During a median follow-up time of 36.5 months, there were 66 (21.7%) recurrences and 76 (25.0%) deaths. The ROC curve showed optimal Youden indices were 4, 1.5, and 4 ng/mL at pretreatment, treatment, and recurrence, respectively. In patients with SCC-Ag ≥ 4 ng/mL, not SCC-Ag < 4 ng/mL before treatment, post-treatment SCC-Ag level (≥ 1.5 ng/mL vs. < 1.5 ng/mL) showed significant differences in 3-year RFS (65.5% vs. 45.0%, p < 0.001) and OS (78.5% vs. 55.4%, p < 0.001). In 66 recurrent patients, patients with SCC-Ag ≥ 4 ng/mL at recurrence showed a significantly lower OS rate than others (59.5% vs. 33.0%, p = 0.041).
SCC-Ag level after treatment and at recurrence was useful for predicting recurrence and survival only when its pretreatment value was high (≥ 4 ng/mL).