Cervical cancer response to neoadjuvant chemoradiotherapy: MRI assessment compared with surgery

Background Imaging findings of residual cervical tumor after chemoradiotherapy can closely resemble those of post-irradiation inflammation. Purpose To determine the diagnostic performance of magnetic resonance imaging (MRI) in evaluating residual disease after chemoradiotherapy in patients with locally advanced cervical carcinoma (LACC). Material and Methods Retrospective analysis of prospectively collected data from 41 patients with histopathologically proven LACC (International Federation of Gynecology and Obstetrics stage IB2) who underwent MRI before and after chemoradiotherapy. At each examination, a qualitative and semi-quantitative analysis of primary tumor, including tumor volume and signal intensity were assessed on T2-weighted (T2W) images. All patients had surgery after post-chemoradiotherapy MRI. MRI and histopathologic results were compared. Results All patients showed significant difference in tumor volume and signal intensity between pre- and post-chemoradiotherapy MRI (P<0.0001). According to pathology, 27/41 (66%) patients had true negative and 2/41 (5%) had true positive post-chemoradiotherapy MRI. Eleven out of 41 (27%) patients showed inflammation with false positive post-chemoradiotherapy MRI and 1/41 (2%) had a false negative post-chemoradiotherapy MRI. Sensitivity, specificity, accuracy, positive predictive values, and negative predictive values of post-chemoradiotherapy MRI in predicting residual disease were 69%, 71%, 71%, 15%, and 96%, respectively. Conclusion The differentiation of residual tumor from post-irradiation inflammation with early post- chemoradiotherapy MRI (within 28-60 days) is difficult with a high risk of false positive results. Combination of qualitative and semi-quantitative analysis does not improve the accuracy. Conversely, post-chemoradiotherapy MRI has a high negative predictive value with a low risk of false negative results. The role of conventional MRI combined with functional techniques should be evaluated.