Can dynamic MR imaging predict response in patients with rectal cancer undergoing cetuximab-based neoadjuvant chemoradiation?

Abstract

Background: The aim of this study was to evaluate therapy response in patients undergoing cetuximab-CapIri-based chemoradiation for rectal cancer using dynamic magnetic resonance imaging (dMRI).

Patients and methods: The volumetric degree of tumor regression and contrast media perfusion were compared to the results of the histopathologic ypTN staging. 33 patients were examined using a 1.5-T scanner with repetitive 2D FLASH sequences after contrast media application. All patients were examined twice - before therapy and immediately before surgery.

Results: In all patients, the tumor volume decreased (mean 72 +/- 16%). In 25/33 patients, the slope of the contrast media enhancement curve decreased (mean 31 +/- 20%). In histopathologically proven downstaging after therapy, the decrease in slope was significantly higher than in the group without downstaging, and the decrease in slope was better for distinguishing between 'responder' and 'non-responder' than the decrease in volume.

Conclusion: Using dMRI helps to identify responders undergoing cetuximab-based chemoradiation better than volume decrease alone.