Costs and outcomes of Lynch syndrome screening in the Australian colorectal cancer population.

Cenin DR1,2,3, Naber SK1, Lansdorp-Vogelaar I1, Jenkins MA4, Buchanan DD4,5,6,7, Preen DB3, Ee HC8, O'Leary P2,9,10.

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Abstract

BACKGROUND AND AIM:

Individuals with Lynch syndrome (LS) are at increased risk of LS-related cancers including colorectal cancer (CRC). CRC tumor screening for mismatch repair (MMR) deficiency is recommended in Australia to identify LS, although its cost-effectiveness has not been assessed. We aim to determine the cost-effectiveness of screening individuals with CRC for LS at different age-at-diagnosis thresholds.

METHODS:

We developed a decision-analysis model to estimate yield and costs of LS screening. Age-specific probabilities of LS diagnosis were based on Australian data. Two CRC tumor screening pathways were assessed (MMR immunohistochemistry (IHC) followed by MLH1 methylation (MLH1-Pathway) or BRAF V600E testing (BRAF-Pathway) if MLH1 expression was lost) for four age-at-diagnosis thresholds - Screening<50, Screening<60, Screening<70 and Universal screening.

RESULTS:

Per 1,000 CRC cases, Screening<50 identified 5.2 LS cases and cost A$7,041 per case detected in the MLH1-Pathway. Screening<60 increased detection by 1.5 cases for an incremental cost of A$25,177 per additional case detected. Screening<70 detected 1.6 additional cases at an incremental cost of A$40,278 per additional case detected. Compared to Screening<70, Universal screening detected no additional LS cases, but cost A$158,724 extra. The BRAF-Pathway identified the same number of LS cases for higher costs. Per 1,000 CRC cases, Screening<50 identified 5.2 LS cases and cost A$7,041 per case detected in the MLH1-Pathway. Screening<60 increased detection by 1.5 cases for an incremental cost of A$25,177 per additional case detected. Screening<70 detected 1.6 additional cases at an incremental cost of A$40,278 per additional case detected. Compared to Screening<70, Universal screening detected no additional LS cases, but cost an extra A$158,724. The BRAF-Pathway identified the same number of LS cases for higher costs.

CONCLUSIONS:

The MLH1-Pathway is more cost-effective than BRAF-Pathway for all age-at-diagnosis thresholds. MMR IHC tumor screening in individuals diagnosed with CRC aged <70 years resulted in higher LS case detection at a reasonable cost. Further research into the yield of LS screening in CRC patients ≥70 years is needed to determine if Universal screening is justified.