Predicting Residual Rectal Adenocarcinoma in the Surgical Specimen after Preoperative Brachytherapy with Endoscopic Ultrasound
Notice bibliographique
Résumé
BACKGROUND AND STUDY AIMS: A novel brachytherapy (BT) protocol evaluated at McGill University has shown promise in terms of downstaging and achieving high tumour sterilization rates in rectal cancer. Endoscopic ultrasound (EUS) has emerged as the imaging modality of choice for local staging of rectal cancer. However, external beam radiotherapy appears to decrease the accuracy of EUS from 85% to 40%. The aim of the present study was to prospectively evaluate the accuracy of EUS in assessing the response of rectal cancer to BT. PATIENTS AND METHODS: Thirty-three patients with locally advanced (stage T2 or T3) operable rectal carcinomas were included in an experimental protocol involving a novel conformal technique, using three-dimensional planning, to administer high-dose rate preoperative BT. The 18 patients who were able to have a post-BT EUS exam arranged within two weeks before surgery (eg, four to eight weeks post-BT) were included in this study. Tumour (T)- and lymph node (N)-staging on radial EUS, as well as interpretation of the residual tumour, were assessed prospectively. Pathologists were blinded to the post-BT EUS results. RESULTS: The mean age was 70 years (SD +/- 11; range, 52 to 93 years) and 78% of the patients were male. Pre-BT EUS indicated that 16 patients (89%) were stage T3, and two were stage T2. Five patients (28%) had positive nodes (N1) by ultrasound. With BT, the mean maximal wall thickness on EUS decreased from 14 mm to 9.4 mm (P<0.001). At the time of surgery, seven of the 18 patients (39%) had no detectable tumour in the resected specimen; one had carcinoma in situ, one was stage T1, one was stage T2, and eight were stage T3. Eleven patients (61%) underwent an abdominoperineal resection, including four of the 11 (36%) with no ultimate evidence of residual carcinoma. Eight patients (44%) were node-positive. The sensitivity, specificity, and positive and negative predictive values of post-BT EUS in predicting residual tumour were 82%, 29%, 64% and 50%, respectively. The post-BT EUS accurately predicted the T-stage in eight (44%) patients; most errors were due to overstaging. CONCLUSIONS: Rectal cancer T-staging by EUS post-BT is inaccurate, and although it appears sensitive in predicting the presence or absence of residual tumor in rectal adenocarcinoma after preoperative BT, the low predictive values in this setting limit its utility at this time.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».