Predictive value of mrSSS score for pathological complete response after neoadjuvant chemoradiotherapy for patients with rectal cancer

Motivation: Patients with rectal cancer who have pathological complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) are the best candidates to receive nonoperative management. An optimized method to identify these patients remains to be developed. Goal(s): To measure the diagnostic performance of modified MRI-based split scar sign (mrSSS) score. Approach: The sensitivity, specificity, and accuracy of modified mrSSS score, endoscopic gross type, and MRI-based tumor regression grading (mrTRG) score, in the prediction of pCR, were compared. The prognostic value was also studied. Results: The modified mrSSS score had significantly higher sensitivity in predicting pCR. Patients with lower modified mrSSS scores had significantly longer disease-free survival. Impact: The modified mrSSS score showed satisfactory interobserver agreement and higher sensitivity in predicting pCR after nCRT in patients with rectal cancer. The modified mrSSS score is also a predictor of disease-free survival.