63 Evolutions in rectal cancer MRI staging and risk stratification in the Netherlands 4 Figure 2 Changes in nodal stage after re-evaluation of cases using updated nodal staging criteria. Discussion This study demonstrates that novel concepts of risk stratification such as cT3-substaging and reporting of EMVI have increasingly been adopted in radiological reports in MRI reporting in the Netherlands from 2011 to 2018. During the same period, we have observed a clear increase in the use of structured reporting templates and an overall trend towards improved completeness of reporting. When retrospectively applying updated criteria for risk stratification, as adopted by recent guidelines, this might have resulted in a change in risk status in approximately 18% of patients in our cohort. The main factors that changed the risk stratification were a reduction in the number of patients classified as high risk based on cT-stage and a reduced number of patients staged as node-positive. Of the 483 patients staged as cT3-4 in the original reports, only 223 (46.2%) were categorized as having a high risk cT-stage (≥cT3cd) when applying updated criteria for cT-staging where only tumors with an invasion depth of >5 mm beyond the rectal wall are considered high risk tumors (1,3,14). In the remaining 53.8% of cases, re-evaluation including cT-substaging revealed a low-risk cT-stage (≤cT3ab), which – provided that no other risk criteria are present – may be treated surgically without the necessity for neoadjuvant treatment (13), though in some countries and guide-
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