A pilot study: ensuring optimal adjustment for determinations of predictive values of preoperative investigations before starting a non-operative management protocol in locally advanced mid-distal rectal cancer

Abstract

Purpose: Before starting a non-operative-management (NOM) protocol in locally advanced mid-distal rectal cancer, we have conducted a pilot study to find out the predictive value of our preoperative investigations. Methods: Between 2013 and 2017, 35 patients with locally advanced (cT3-4, N-any) primary mid-distal rectal adenocarcinoma were included in the study. We had two groups: Standard long-term chemoradiotherapy (CRT) (Group-1) and CRT + Consolidation chemotherapy (Group-2) groups. Both groups were evaluated regarding clinical (endoscopic-radiological) and pathologic response to neoadjuvant therapy. Each patient's data were prospectively recorded and findings were assessed according to NOM protocol and the clinical decisions recorded. The study was oriented to specify the predictive value of oncology team's hypothetical decisions in determining the right candidate for nonoperative management of rectal cancer. All patients underwent surgery with total mesorectal excision (TME) technique; thus, the hypothetical clinical decisions and pathologic results were compared. Results: The sensitivity and specificity of endoscopy were 57.1% and 87.5%; PPV was 80%, NPV was 70%, and accuracy was 73.3%. The sensitivity of MRI tumor regression grade scoring was 60%, specificity was 90%, PPV was 75%, NPV was 81.8%, and accuracy was 80%. The sensitivity and specificity of the final clinical decision were 80% and 90%; PPV was 80%, NPV was 90%, and accuracy was 86.6% in predicting proper management Conclusion: An institutional adjustment for determinations of predictive values of preoperative investigations is beneficial before the start of nonoperative management protocol.