58 Chapter 4 and re-evaluation reports (using updated guideline criteria) were available. These patients included 95 (13.3%) patients who were treated with direct surgery, 61 (8.6%) patients who underwent short-course radiotherapy (5x5 Gy) followed by surgery, and 556 (78.1%) patients who underwent a long course of neoadjuvant treatment (i.e., chemoradiotherapy or 5x5 Gy with an extended waiting interval to surgery). Type and completeness or reporting Table 2 demonstrates evolutions in the type and completeness of reporting over time. During the study inclusion period, a significant decrease in free-text reporting and corresponding increase in template reporting was observed, with template reports constituting 17.6%-29.6% of all reports in the second and third part of the study period (vs. only 1.6% in the first period; p<0.001). Items that were consistently reported in ≥80% of reports (regardless of the study period) included tumor height, length, cT- and cN-stage (as cN0/cN+). A significant increase over time was observed for the reporting of cT-substage (cT3abcd and cT4ab), number of suspicious lymph nodes (incl. substaging of N-stage as cN0/1/2 and the presence of suspicious extramesorectal lymph nodes), MRF invasion, distance between tumor and MRF, EMVI, anal sphincter invasion, tumor morphology and tumor circumference. Risk stratification Figure 1 demonstrates the categorization of patients into low risk versus high risk according to the original staging reports and shows how this categorization was affected after re-evaluation using updated staging criteria (including cT-substaging as cT3ab versus cT3cd, updated nodal staging criteria and implementation of EMVI). These results could be analyzed for 604 out of the 712 study patients; for the remaining 108 patients one or more required staging items (cT-stage, cN-stage or MRF invasion) were missing from the original staging reports. Re-evaluation of the patient cases changed the risk classification from high to low risk in 109/604 (18.0%) cases and from low to high risk in 10/604 (1.7%) cases (total 119; 19.7%). In 11 out of these 119 cases, the change in risk classification was mainly due to interpretation differences between the original staging reports and the expert-re-evaluation, including downstaging of cT4 tumors to low-risk cT12-3ab disease and conversion from MRF+ to MRF- stage or vice versa. The remaining 108 cases (17.9%) with a change in risk classification were mainly attributable to changes in the classification of high-risk cT-stage and changes in cN-stage. Figure 2 provides a more detailed overview of the changes in cN-stage (using updated nodal staging criteria), which resulted in nodal downstaging in 35.7% of cases and nodal upstaging in 8.5% of cases. In the remaining 55.7% of cases cN-stage remained concordant.
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