Selection of Patients With Rectal Cancer for Preoperative Chemoradiotherapy: Are T Category and Nodal Status All That Matters?
Bibliographic record
Abstract
BACKGROUND: Although the accuracy of preoperative MRI staging has been established on follow-up histopathologic examination, the reproducibility of MRI staging has been evaluated in studies with expert radiologists reading a large sample of MRI images and therefore is not generalizable to the real-world setting. OBJECTIVE: The purpose of this study was to evaluate the interrater reliability of MRI for distance to the mesorectal fascia, T category, mesorectal lymph node status, and extramural depth of invasion for preoperative staging of primary rectal cancer. DESIGN: This was a prospective, cross-sectional survey. SETTINGS: The study was conducted in Ontario, Canada. PARTICIPANTS: Participants included GI radiologists. INTERVENTIONS: Participants read 5 preselected staging MRIs using a synoptic report and participated in an educational Webinar. MAIN OUTCOME MEASURES: Distance to the mesorectal fascia, T category, extramural depth of invasion, and mesorectal lymph node status for each MRI were abstracted. Data were analyzed in aggregate using percentage of agreement, Fleiss κ, and interclass correlation coefficients to assess interrater reliability. RESULTS: Reliability was highest for distance to the mesorectal fascia with an intraclass correlation of 0.58 (95% CI, 0.27-0.80). Kappa scores for T category, mesorectal lymph node status, and extramural depth of invasion were 0.38 (95% CI, 0.23-0.46), 0.41 (95% CI, 0.32-0.49), and 0.37 (95% CI, 0.16-0.82). There was no difference when radiologists were stratified by experience or volume. LIMITATIONS: Scores may have been affected by MRI selection, because they were chosen to demonstrate diagnostic challenges for the Webinar and did not reflect a representative sample. CONCLUSIONS: Interrater reliability was highest for distance to mesorectal fascia, and therefore, it may be a more reliable criterion than T category, extramural depth of invasion, or mesorectal lymph node status. Combined with the fact that an uninvolved mesorectal fascia is more consistent with the overall goal of rectal cancer surgery, it should be considered as an important MRI criterion for preoperative treatment decision making in the real-world setting. See Video Abstract at http://links.lww.com/DCR/A763.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.010 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".