Background: Distinguishing hereditary non-polyposis colorectal cancer (HNPCC) from non-hereditary colorectal cancer (CRC) can increase the life expectancy of HNPCC patients and their close relatives.
Aim: To determine the effectiveness, efficiency, and feasibility of a new strategy for the detection of HNPCC, using simple criteria for microsatellite instability (MSI) analysis of newly detected tumours that can be applied by pathologists. Criteria for MSI analysis are: (1) CRC before age 50 years; (2) second CRC; (3) CRC and HNPCC associated cancer; or (4) adenoma before age 40 years.
Methods: The efficacy and cost effectiveness of the new strategy was evaluated against current practice. Decision analytic models were constructed to estimate the number of extra HNPCC mutation carriers and the costs of this strategy. The incremental costs and gain in life expectancy for a HNPCC mutation carrier were evaluated by Markov modelling. Feasibility was explored in five hospitals.
Results: Using the new strategy, 2.2 times more HNPCC patients can be identified among a CRC population compared with current practice. This new strategy was found to be cost effective with an expected cost effectiveness ratio of 3801 per life year gained. When including the group of siblings and children, the cost effectiveness ratio became 2184 per life year gained. Sensitivity analysis showed these findings to be robust.
Conclusions: MSI testing in a selection of newly diagnosed CRC patients was shown to be cost effective and a feasible method to identify patients at risk for HNPCC who are not recognised by family history.