Screening for Lynch syndrome and referral to clinical genetics by selective mismatch repair protein immunohistochemistry testing: an audit and cost analysis
Bibliographic record
Abstract
Lynch syndrome (LS) accounts for around 3% of colorectal cancers (CRCs) and is caused by germline mutations in mismatch repair (MMR) genes. Recently, screening strategies to identify patients with LS have become popular. We audited CRCs screened with MMR immunohistochemistry (IHC) in 2013. 209 tumours had MMR IHC performed at a cost of £12 540. 47/209 (21%) cases showed IHC loss of expression in at least one MMR protein. 28/44 cases with loss of MLH1 had additional BRAF V600E testing, at a cost of £5040. MMR IHC reduced the number of potential clinical genetics referrals from 209 to 47. BRAF mutation testing, performed in a subset of cases with MLH1 loss, further reduced this to 21. At a cost of £1340 per referral, this model of LS screening for clinical genetics referral had significant potential savings (£234 340) and can be easily implemented in parallel with MMR IHC done for prognostication in CRCs.
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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 | 0.004 | 0.019 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".