Magnetic resonance imaging as a predictor of surgical outcome in patients with local pelvic recurrence of colorectal cancer.

INTRODUCTION: Pelvic local recurrence of colorectal cancer (PRCRC) may be cured if radical surgery is performed. Preoperative assessment normally includes magnetic resonance imaging (MRI). The aim of this study was to evaluate the influence of specific MRI-related findings on outcome of surgery of PRCRC.

MATERIALS AND METHODS: Clinical data from 95 consecutive patients, operated with a curative intent for PRCRC at Karolinska University Hospital during 2003-2013, were collected from medical records. Preoperative MRI examinations of the PRCRC were re-evaluated. The potential influence of clinical factors and specific MRI-findings (location, solid/mucinous, size, volume and border) on surgical resection margins (R0-R1) and survival were calculated with logistic and cox regression.

RESULTS: Eighty-seven patients had available MRI scans and were included in the study. Sixty-five patients (75%) had a R0 resection and 22 patients (25%) had a R1 resection of their PRCRC. In all, 47 patients (54%) had an involved lateral compartment. Lateral location was the only MRI finding associated with both an increased risk of R1 resection (OR 3.97, 95%CI: 1.31-12.04) and death (HR 1.94, 95%CI: 1.07-3.51). Lateral location entailed an increased risk of death also after R0 resection (HR2.09, 95%CI: 1.07-4.10). Five-year survival was 35% for all patients, 44% after R0 resection and 7% after R1 resection.

CONCLUSION: Tumour involvement of the lateral and posterior compartments on MRI was a predictor for R1 resection, but only lateral involvement was associated with an increased risk of death. An increased risk of death associated with lateral involvement was still present after R0 resection.