Abstract B011: Circulating tumor DNA profiling in colorectal cancer to detect guideline-based targeted mutations at a Quebec health care center
Notice bibliographique
Résumé
Abstract Liquid biopsy is an emerging tool in oncology, providing minimally invasive detection of tumor- specific DNA in body fluids, known as circulating tumor DNA (ctDNA). Colorectal cancer (CRC) has shown a high rate of shedding of ctDNA, making it a promising prognostic and possibly predictive biomarker in the personalized management of patients with CRC. Therefore, the half-life of ctDNA in circulation is estimated to be between 16 minutes and several hours, indicating a need for rapid processing. This study aimed to explore the concordance between the mutational profiles in tumor tissue and ctDNA from plasma obtained using EDTA tubes as well as the correlation between ctDNA and disease stage, to evaluate the potential of implementing liquid biopsy testing in CRC cases, following biobank standards. In this retrospective cohort, 58 patients with CRC stage T1 to T4 were enrolled at the Research Institute McGill University Health Centre (RI-MUHC). Tumor tissue was obtained through surgical resection or biopsies of formalin-fixed paraffin-embedded tissue, and blood samples were drawn pre-surgery using EDTA tubes. Cell-free DNA (cfDNA) was extracted from 1-2mL plasma samples using QIAamp Circulating Nucleic Acids. Next-Generation Sequencing using a 52-gene (AmpliSeq for Illumina Focus Panel) was performed to identify the tumor mutations and subsequently droplet digital PCR (ddPCR) was performed to identify the plasma mutations. Among the 58 patients, the mean age was 62 years (range 29-86), and 29 were women. Forty- one patients had left-sided tumor. At least 1 tumor-specific mutation was detected in all tissue tumor samples. Overall, the most frequently identified mutations in this cohort were: BRAF V600E (22.4%), KRAS G12D (12.1%), KRAS G12V and KRAS G13D (8.6%). Cell-free DNA was obtained from 32 patients and showed a mean concentration of 975 ng/mL (range 400- 1,995) for stage T1, 584 ng/mL (range 228-1,300) for stage T2, 1,127 ng/mL (range 249-4,160) for stage T3 and 2,083 ng/mL (range 860-3,680) for stage T4. ddPCR revealed mutation concordance between ctDNA and matched tumor tissue of 28.1%. When tumors were stratified by stage, the concordance was 0% (n=0/3) in patients with T1 tumors, 16.7% (n=1/6) in patients with T2 tumors, 25% (n=5/20) in patients with T3 tumors and 100% (3/3) in patients with T4 tumors. This study showed that ctDNA detection of mutations has excellent concordance in stage T4 tumors, highlighting the potential of ctDNA in advanced stage disease. However, in T1-3 tumor stages the concordance was low, showing the importance of preanalytical steps such as the use of cell-free DNA preservative tubes for sensitive and accurate detection of ctDNA in patients with earlier stage disease. Citation Format: Monyse de Nobrega, Kyle Dickinson, Saba Alsaddah, Alexandra Bartolomucci, Tadhg Ferrier, Anne Mahalia Olivier Mahalia Olivier, Mina Farag, Gertuda Evaristo, Sophie Camilleri-Broet, Andrea Gomez, Thupten Tsering, Lawrence Lee, Pierre Olivier Fiset, Julia V. Burnier. Circulating tumor DNA profiling in colorectal cancer to detect guideline-based targeted mutations at a Quebec health care center [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr B011.
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 | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 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) | 0,006 | 0,001 |
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 ».