Sensitivity of Various Evaluating Modalities for Predicting a Pathologic Complete Response After Preoperative Chemoradiation Therapy for Locally Advanced Rectal Cancer

摘要

Purpose: We investigated the sensitivity of various evaluating modalities in predicting a pathologic complete response(pCR) after preoperative chemoradiation therapy (PCRT) for locally advanced rectal cancer (LARC).Methods: From a population of 2,247 LARC patients who underwent PCRT followed by surgery at Asan Medical Center,Seoul, Korea from January 2007 to June 2016, we retrospectively analyzed 313 patients (14.1%) who showed a pCR aftersurgery. Transrectal ultrasound (TRUS), high-resolution magnetic resonance imaging (MRI), abdominopelvic computedtomography (AP-CT), and endoscopy were performed within 2 weeks prior to surgery.Results: Of the 313 patients analyzed, 256 (81.8%) had a pCR after radical surgery and 57 (18.2%) showed total regressionafter local excision. Preoperative TRUS, MRI, and AP-CT were performed in 283, 305, and 139 patients, respectively.Among these 3 groups, a prediction of a pCR of the primary tumor was made in 41 (14.5%), 51 (16.7%), and 27 patients(19.4%), respectively, before surgery. A prediction of a clinical N0 stage was made in 204 patients (88.3%) using TRUS,130 (52.2%) using MRI, and 78 (65.5%) using AP-CT. Of the 211 patients who underwent endoscopy, 87 (41.2%) had amention of clinical CR in their records. A prediction of a pathologic CR was made for 124 patients (39.6%) through atleast one diagnostic modality.Conclusion: The various evaluation methods for predicting a pCR after PCRT show a predictive sensitivity of 0.15–0.41for primary tumors and 0.52–0.88 for lymph nodes. Endoscopy is a relatively superior modality for predicting the pCR ofthe primary tumor of LARC patients.