Prognostic Utility of Squamous Cell Carcinoma Antigen in Carcinoma of the Cervix: Association With Pre- and Posttreatment FDG-PET

Purpose: Squamous cell carcinoma antigen (SCC Ag) is a serum biomarker for squamous cell carcinoma (SCC) of the cervix. We investigated the prognostic significance of SCC Ag levels before and at the completion of chemoradiotherapy and compared these levels with the results of pre- and posttreatment positron emission tomography/computed tomography (PET/CT) using [18F]fluorodeoxyglucose (FDG). Methods and Materials: The records of 63 women who underwent definitive chemoradiotherapy for SCC of the cervix were reviewed. SCC Ag levels were obtained before and at the completion of radiotherapy. Patients were divided into two groups on the basis of their pretreatment SCC Ag level (>30 ng/mL vs. ≤30 ng/mL). Pre- and posttreatment FDG-PET/CT characteristics and progression-free survival (PFS) were analyzed according to SCC Ag groups. Results: Median follow-up was 12 months. Women with SCC Ag >30 ng/mL at diagnosis had more advanced lymph node disease on pretreatment FDG-PET/CT than those with SCC Ag ≤30 ng/mL (p = .002). Women whose SCC Ag normalized at the completion of chemoradiotherapy were more likely to have a complete metabolic response on their 3-month posttreatment FDG-PET/CT than those whose SCC Ag did not normalize (p = .006). The 2-year PFS was 73% for patients with a SCC Ag level ≤30 ng/mL at diagnosis compared with 0% for those with a SCC Ag level >30 ng/mL at diagnosis (p < .0001). The 2-year PFS was 62% for patients whose SCC Ag normalized at the completion of chemoradiotherapy compared with 0% for those whose SCC Ag did not normalize (p = .0004). Conclusion: Elevated SCC Ag at diagnosis and failure of the SCC Ag to normalize at the completion of treatment are associated with incomplete metabolic response and decreased PFS.