OBJECTIVES : Genetic testing is recommended for patient with colorectal cancer (CRC) to identify Lynch syndrome (LS), with subsequent screening of family members and annual colonoscopy for positives. Previous studies have found such an approach is cost effective, and that the number of family members tested is a key driver. However, it is not clear whether a tool to improve family communication regarding test results may be a cost-effective intervention. A cost-effectiveness threshold analysis would be helpful in determining the threshold value of the effectiveness of communication to be cost-effective.

METHODS : We developed a decision tree and Markov model, which consists four states: well, CRC (1^st year), post CRC (2-5 years) and death. CRC prevalence, utilities, and costs were derived from published literature and secondary databases. Life-years gained and quality-adjusted life-years (QALYs) by family members were evaluated.

RESULTS : A deterministic threshold analysis showed that the communication intervention will be cost-effective under $50k/QALY ICER threshold if the effectiveness improves at least 0.4%, with incremental costs $110 and incremental QALYs 0.002 compared with no communication tool when the cost of communication tool is given at $100. Additionally, the analysis showed that the effectiveness of communication tool would improve at least 1% (Incr.cost=$275, Incr.QALY=0.005) and 2% (Incr. cost=$550, Incr.QALY=0.01) in order to be a cost-effective intervention under $50k/QALY ICER threshold when the communication tool costs $250 and $500, respectively.

CONCLUSIONS : This study identified the level at which the effectiveness of a family communication intervention will be cost-effective in USA. Our findings could be a useful aid for decision makers in efficiently allocating limited resources when planning family communication tool for CRC patients positive for LS and their FDRs, in order to improve the rate of taking genetic test and colonoscopy and to reduce CRC mortality accordingly.