Evaluation of the role of MRI in staging rectal cancer within the multidisciplinary team setting

Abstract

3611 Background: The multidisciplinary team (MDT) functions to implement an agreed preoperative treatment strategy for rectal cancer; however, its benefits are unproven. In rectal cancer, presence of tumor at the circumferential margin (R1/R2) is a strong predictor of local recurrence and poor survival with published R1/R2 resection rates of 15–25%. We assessed preoperative MDT discussion of MRI scans and impact of strategy on R1/R2 resection rates in all rectal cancer patients treated between January 1999 and December 2002. Methods: Preoperative MDT discussion of MRI appearances categorized disease as: 1. Favorable: T3 <5mm extramural spread, <4 suspicious nodes, safe potential resection margin –for primary surgery. 2. Locally advanced: T3 >5mm or 4 or more suspicious nodes or tumor involving the potential mesorectal resection margin - for preoperative chemoradiotherapy. 3. Palliative: irresectable metastatic disease on CT scan - for palliative treatment. Local spread and presence of tumor at the resection margins was assessed on histology. Results: There were 301 patients with rectal cancer. Of these, only 34(11%) were classified as palliative. In 67/301 patients, the referring team chose not to undertake MDT discussion of MRI findings prior to primary surgery. The remaining 200 patients had preoperative discussion of MRI. 106/200 showed favorable disease on MRI and underwent primary total mesorectal excision surgery. The remaining 94 patients had locally advanced disease (64/94 had potential resection margin involved by tumour) and received preoperative chemoradiotherapy prior to surgery. The R1/R2 resection rate for those patients undergoing primary surgery for MRI defined favorable disease was 2/106 (2%) compared with 16/67 (24%) in those without MDT discussion of MRI. The overall R1/R2 resection rate for 200 patients with MDT discussion was 17/200 (8.5%), significantly less than the R1/R2 rates in those not undergoing MDT discussion of MRI (p<0.001) and significantly less than published standards. Conclusions: MDT discussion of preoperative MRI with implementation of a selective preoperative strategy significantly reduces R1/R2 resections. No significant financial relationships to disclose.