Purpose: Comparison of diagnostic accuracy of staging of endorectal sonography (ES) and body coil MRI after preoperative hyperthermoradiochemotherapy in patients with advanced rectal cancer.
Methods: Prospective analysis of MRI and ES in 30 patients after hyperthermoradiochemotherapy and correlation with histopathological patterns.
Results: T-staging by MRI was correct in 47% and by ES in 53% of the cases. Despite similar accuracy of staging in T0- and T1-tumours, we found different accuracies concerning T2-tumour staging about 63% versus 73% (MRI/ES), concerning perirectal infiltration 70% for both techniques, concerning invasion of adjacent organs 90% versus 87%, and concerning lymph node metastases without respect to the N-stage 63% versus 63%.
Conclusion: Both imaging modalities provide useful information for operation planning despite limited accuracy after hyperthermoradiochemotherapy. The body coil MRI does not seem to be severely inferior to ES in post-therapeutic staging, despite better contour line imaging by ES. With respect to the determination of invasion of other organs, MRI seems to be more useful.