Preoperative magnetic resonance imaging assessment of circumferential resection margin predicts disease-free survival and local recurrence: 5-year follow-up results of the MERCURY study

J Clin Oncol. 2014 Jan 1;32(1):34-43. doi: 10.1200/JCO.2012.45.3258. Epub 2013 Nov 25.


Purpose: The prognostic relevance of preoperative high-resolution magnetic resonance imaging (MRI) assessment of circumferential resection margin (CRM) involvement is unknown. This follow-up study of 374 patients with rectal cancer reports the relationship between preoperative MRI assessment of CRM staging, American Joint Committee on Cancer (AJCC) TNM stage, and clinical variables with overall survival (OS), disease-free survival (DFS), and time to local recurrence (LR).

Patients and methods: Patients underwent protocol high-resolution pelvic MRI. Tumor distance to the mesorectal fascia of ≤ 1 mm was recorded as an MRI-involved CRM. A Cox proportional hazards model was used in multivariate analysis to determine the relationship of MRI assessment of CRM to survivorship after adjusting for preoperative covariates.

Results: Surviving patients were followed for a median of 62 months. The 5-year OS was 62.2% in patients with MRI-clear CRM compared with 42.2% in patients with MRI-involved CRM with a hazard ratio (HR) of 1.97 (95% CI, 1.27 to 3.04; P < .01). The 5-year DFS was 67.2% (95% CI, 61.4% to 73%) for MRI-clear CRM compared with 47.3% (95% CI, 33.7% to 60.9%) for MRI-involved CRM with an HR of 1.65 (95% CI, 1.01 to 2.69; P < .05). Local recurrence HR for MRI-involved CRM was 3.50 (95% CI, 1.53 to 8.00; P < .05). MRI-involved CRM was the only preoperative staging parameter that remained significant for OS, DFS, and LR on multivariate analysis.

Conclusion: High-resolution MRI preoperative assessment of CRM status is superior to AJCC TNM-based criteria for assessing risk of LR, DFS, and OS. Furthermore, MRI CRM involvement is significantly associated with distant metastatic disease; therefore, colorectal cancer teams could intensify treatment and follow-up accordingly to improve survival outcomes.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Analysis of Variance
  • Confounding Factors, Epidemiologic
  • Disease Progression
  • Disease-Free Survival
  • Europe
  • Female
  • Follow-Up Studies
  • Humans
  • Kaplan-Meier Estimate
  • Magnetic Resonance Imaging*
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / diagnosis*
  • Neoplasm Staging
  • Odds Ratio
  • Predictive Value of Tests
  • Preoperative Period
  • Prognosis
  • Proportional Hazards Models
  • Rectal Neoplasms / diagnosis*
  • Rectal Neoplasms / mortality
  • Rectal Neoplasms / pathology
  • Rectal Neoplasms / surgery*
  • Research Design