A164 OPTIMIZING A PROVINCIAL SCREENING PROGRAM FOR DETECTION OF LYNCH SYNDROME
Bibliographic record
Abstract
Abstract Background Up to 30% of those with colorectal cancer (CRC) have an affected family member. Lynch syndrome (LS) is the most common inherited condition predisposing patients to CRC. LS is an autosomal dominant condition associated with microsatellite instability (MSI) and mutations in DNA mismatch repair (MMR) genes, and screening CRC cases ≤ age 70 can identify LS in a cost-effective manner. Manitoba launched Canada's first provincial reflex screening program for all CRC cases diagnosed ≤ age 70 using MMR immunohistochemistry (MMR-IHC) in 2017. Our prior 2022 study evaluating the program showed compliance rates of 89.4% for MMR-IHC reflex testing and a 75.8% overall referral rate of screen-positive cases to genetics. However, only 50% were referred directly by pathologists. Several modifications have since been implemented to enhance the program. These included providing feedback to pathologists, creating an “additional testing comment section” on synoptic pathology reports, and regular review of the pathology reports by a pathology assistant. Information materials were developed to encourage genetic testing among relatives. Aims Assess whether modifications to Manitoba’s universal screening protocol improved LS patient outcomes and determine any remaining factors to optimize. We specifically aimed to identify current compliance rates for MMR-IHC testing, the overall referral rate of screen-positive cases to genetics, uptake of genetic referrals and genetic testing as well as rate of cascade testing among relatives. Methods Data has been obtained by searching the provincial pathology database for “adenocarcinoma” in the colorectal specimen pathology reports. All specimens from 2022 and Q1/Q2 of 2023 were reviewed, meeting the criteria of: a) specimen from colon biopsy/excision containing the term “adenocarcinoma”, b) patient age ≤70 years, and c) missing MMR centralized by the IT/Pathology department. Additionally, a random sample of cases categorized as “MMR performed” will be audited. We are in the process of reviewing genetic referrals, genetic uptake and the frequency of reminders triggered to each pathologist. Results Currently, a total of 1,308 colonic adenocarcinoma specimens (811 from 2022, 497 for 2023) have been reviewed. Appropriate MMR testing was missed in only 1.5% of cases (13/811 =1.6% missed in 2022, 7/497= 1.4% missed in 2023). Conclusions Current MMR testing rates for colonic adenocarcinoma specimens within the Manitoba LS screening program have reached a current compliance rate of 98.5%, a substantial improvement from the prior audit (89.4% previously). Further data collection and analysis is ongoing and will also be presented. The reported rates of compliance are the highest that have been reported from any jurisdiction. This study highlights the sustained efforts required to improve detection of LS. Funding Agencies None
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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 | 0.005 | 0.020 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.003 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.001 |
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".