Open Access
26-06-2023 | Rectal Cancer | Hollow Organ GI
Predicting response to chemoradiotherapy in rectal cancer via visual morphologic assessment and staging on baseline MRI: a multicenter and multireader study
Authors:
Najim El Khababi, Regina G. H. Beets-Tan, Renaud Tissier, Max J. Lahaye, Monique Maas, Luís Curvo-Semedo, Raphaëla C. Dresen, Stephanie Nougaret, Geerard L. Beets, Doenja M. J. Lambregts, on behalf of the rectal MRI study group
Pre-treatment knowledge of the anticipated response of rectal tumors to neoadjuvant chemoradiotherapy (CRT) could help to further optimize the treatment. Van Griethuysen et al. proposed a visual 5-point confidence score to predict the likelihood of response on baseline MRI. Aim was to evaluate this score in a multicenter and multireader study setting and compare it to two simplified (4-point and 2-point) adaptations in terms of diagnostic performance, interobserver agreement (IOA), and reader preference.
Methods
Twenty-two radiologists from 14 countries (5 MRI-experts,17 general/abdominal radiologists) retrospectively reviewed 90 baseline MRIs to estimate if patients would likely achieve a (near-)complete response (nCR); first using the 5-point score by van Griethuysen (1=highly unlikely to 5=highly likely to achieve nCR), second using a 4-point adaptation (with 1-point each for high-risk T-stage, obvious mesorectal fascia invasion, nodal involvement, and extramural vascular invasion), and third using a 2-point score (unlikely/likely to achieve nCR). Diagnostic performance was calculated using ROC curves and IOA using Krippendorf’s alpha (α).
Results
Areas under the ROC curve to predict the likelihood of a nCR were similar for the three methods (0.71–0.74). IOA was higher for the 5- and 4-point scores (α=0.55 and 0.57 versus 0.46 for the 2-point score) with best results for the MRI-experts (α=0.64-0.65). Most readers (55%) favored the 4-point score.
Conclusions
Visual morphologic assessment and staging methods can predict neoadjuvant treatment response with moderate–good performance. Compared to a previously published confidence-based scoring system, study readers preferred a simplified 4-point risk score based on high-risk T-stage, MRF involvement, nodal involvement, and EMVI.
Predicting response to chemoradiotherapy in rectal cancer via visual morphologic assessment and staging on baseline MRI: a multicenter and multireader study
Authors
Najim El Khababi Regina G. H. Beets-Tan Renaud Tissier Max J. Lahaye Monique Maas Luís Curvo-Semedo Raphaëla C. Dresen Stephanie Nougaret Geerard L. Beets Doenja M. J. Lambregts on behalf of the rectal MRI study group
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