Cost analysis of alternative approaches to colorectal screening in familial adenomatous polyposis.

Background & Aims: The commercial availability of gene testing for familial adenomatous polyposis (FAP) represents an important advance in screening for inherited colon cancer. We investigated the financial impact of this diagnostic tool on colorectal screening for FAP.
Methods: Decision analysis was used to compare per-person costs with third-party payers of three colorectal screening strategies used to diagnose FAP in at-risk persons. The strategies included conventional serial flexible sigmoidoscopy and two different APC gene testing approaches.
Results: For 1 at-risk relative who begins screening at age 12 years, average screening costs are $2625 when genotyping the proband first, $2674 when genotyping the at-risk relative first, and $3208 for conventional sigmoidoscopy. The cost advantage of genotyping increases as the pedigree size increases. For a pedigree of 5 at-risk relatives, sigmoidoscopy would have to cost less than $85.60 (professional plus facility fee) for conventional screening to compete with genotyping. The cost advantage of genotyping is diminished for at-risk relatives who begin FAP screening at older ages.
Conclusions: The choice of least expensive FAP screening strategy depends on the cost of flexible sigmoidoscopy, patient age when screening starts, and pedigree size. Genotyping can substantially reduce the cost of FAP screening and, when possible, should start with the proband.