591P - Tumor staging with magnetic resonance imaging after neoadjuvant chemoradiation for Locally Advanced Rectal Cancer and comparison of pathologic staging

Date 09 September 2017
Event ESMO 2017 Congress
Session Poster display session
Topics Rectal Cancer
Gastrointestinal Cancers
Imaging, Diagnosis and Staging
Presenter Carolina De la Pinta
Citation Annals of Oncology (2017) 28 (suppl_5): v158-v208. 10.1093/annonc/mdx393
Authors C. De la Pinta, M. Martin, F. López, E. Fernández, A. Hervás, S. Sancho
  • Radiation Oncology, Hospital Universitario Ramon y Cajal, 28031 - Madrid/ES

Abstract

Background

This study was designed to evaluate the role of magnetic resonance imaging (MRI) on preoperative restaging locally advanced rectal cancer after neoadjuvant chemoradiotherapy (CRT), in order to facilitate individualization of surgical management.

Methods

We analyzed 106 patients who had received neoadjuvant CRT underwent a MRI before and after CRT. All patients underwent restaging MRI followed by surgery after the end of CRT. The primary endpoint of the present study was to estimate the accuracy of post-CRT MRI as compared with pathologic staging.

Results

Pathologic T classification matched the post-CRT MRI findings in 38(35.8%) of 106 patients. Sensitivity in T0, T3 and T4 was 25%, 50% and 80% respectively. Specificity in T0, T3 and T4 were 80,2%, 69,7% and 99% respectively. Sensitivity in N0 and N1 were 78,5% and 38,4% respectively. Specificity was 18,2% in N0 and 91,4% in N1. 43 (40,5%) of 106 patients were overstaged in T classification. Pathologic N classification matched the post-CRI MRI findings in 71 (66,7%) of 106 patients. 21(19.8%) of 106 patients were overstaged in N classification. 25 patients (23,6%) achieved T downstaging and 14 patients N dowstaging (13,2%) on restaging MRI after CRT. 24(22,6%) of 106 patients who had been downstaged on MRI after CRT were confirmed on the pathological staging with same stage (T and N).

Conclusions

MRI has low accuracy for restaging locally advanced rectal cancer after preoperative chemoradiation so it is currently not consistent enough for clinical application.

Clinical trial identification

Legal entity responsible for the study

Hospital Ramón y Cajal

Funding

None

Disclosure

All authors have declared no conflicts of interest.