PET/CT response criteria (European Organization for Research and Treatment of Cancer) predict survival better than response evaluation criteria in solid tumors in locally advanced cervical cancer treated with chemoradiation

Purpose To investigate whether the ratio of SUVs measured with ¹⁸F-FDG PET/CT between pretreatment and posttreatment has prognostic value in patients with locally advanced cervical cancer treated with primary chemoradiation therapy. Methods Cases of locally advanced cervical cancer (International Federation of Gynecology and Obstetrics stages IB1 to IVA) treated with a nonsurgical curative modality (172 cases including chemoradiation or radiation therapy) were reviewed. ¹⁸F-FDG PET/CT parameters, including SUVmax and SUVmean, were evaluated by ¹⁸F-FDG PET/CT performed prior to treatment and 6 weeks after the end of treatment. Metabolic response was evaluated according to the European Organization for Research and Treatment of Cancer guidelines and was compared with radiologic response measured according to the Response Evaluation Criteria In Solid Tumours (RECIST). Results In total, 142 patients receiving chemoradiation showed radiologic responses (median 56% decrease in maximal diameter), whereas 160 and 146 patients showed metabolic responses measured with SUVmax and SUVmean, respectively (73% decrease in SUVmax; 48% decrease in SUVmean). Radiologic response and metabolic response were significantly correlated for SUVmax and SUVmean (P = 0.0009; P = 0.0457, respectively). Kaplan-Meier analysis revealed significant differences in overall survival and progression-free survival between the responder and nonresponder groups, based on the European Organization for Research and Treatment of Cancer criteria (both P < 0.001), whereas no significant difference was found when using RECIST criteria (P = 0.058, P = 0.088, respectively). Conclusions ¹⁸F-FDG PET/CT parameters are good prognostic markers for the response of cervical cancer patients to concurrent chemoradiation therapy, as compared with the RECIST criteria.