Usefulness of Short-Term Imaging and Squamous Cell Carcinoma Antigen to Early Predict Response to Concurrent Chemoradiotherapy in Patients With Cervical Cancer

OBJECTIVE: The objective is to investigate the factors that can predict early treatment response in patients receiving concurrent chemoradiotherapy (CCRT) for cervical cancer. METHODS: We assessed clinical factors and treatment response in patients who underwent CCRT for cervical cancer at four time points: initial, 2.5 weeks, 6 weeks after starting CCRT, and 3 months after completing CCRT. The final treatment response was determined by positron emission tomography-computed tomography (PET-CT) 3 months after completion of CCRT. Patients were divided into two groups according to the final treatment response: complete response (CR) group or non-CR group. And the early CCRT response prediction model was developed using stepwise multivariate logistic regression analysis. RESULTS: Of the 62 patients who underwent CCRT for cervical cancer, 57 patients who completed all 4 time points examinations were included in the analyses and classified as CR (n = 32) and non-CR (n = 25) group. Tumor volume and serum squamous cell carcinoma antigen (SCC Ag) of the initial, 2.5 weeks, and 6 weeks after CCRT were significantly associated with the final treatment response. For the early treatment response prediction model, we selected patient age, tumor volume, and SCC Ag measured at initial and 2.5 weeks of CCRT as variables, and the equation of the final model was yielded. Using a cutoff of 0.433, this model had a sensitivity of 72.0%, a specificity of 84.4%, and a probability of 0.8225 (P < .0001). CONCLUSION: Short-term (at 2.5 weeks after starting CCRT) measurements of tumor volume and serum SCC Ag were significant predictors of response to CCRT in patients with cervical cancer.