OBJECTIVES

: Ascertainment of mutational status in high-grade serous cancer of the upper Müllerian tract has implications for family counselling and targeted treatments for platinum-sensitive disease. However, referral rates for genetic counselling vary and reflex tumor testing strategies in pathology laboratories are being explored. This study evaluated the comparative cost impact of reflex panel tumor testing for mutations compared to standard counselling-directed testing.

METHODS

: Three decision analytic cost models comparing a counselling-directed referral to medical genetics vs. reflex tumor testing in pathology laboratories were constructed. Models represent variable use of confirmatory germline panel testing following reflex tumor testing: 1. Germline panel testing done only after a positive tumour panel test 2. Germline panel testing done for all patients 3. Only BRCA1/2 testing done on tumor and germline panel testing subsequently done for all patients. Literature and institutional data were used to generate probability and cost estimates for genetic counselling and mutational evaluations. The primary outcome was ascertainment of somatic and/or germline mutation in any gene within the panel. Comparative cost effectiveness was represented as an incremental cost-effectiveness ratio (ICER) and all costs are shown in undiscounted adjusted 2018 Canadian dollars.

RESULTS

: In models 1 and 3, the reflex tumor testing arm was dominant, indicating that it was less costly on a mean per patient basis and also detected more gene mutations. Corresponding ICER values are $1,790 for model 1 and $1,852 for model 3. In model 2, the reflex testing arm was more costly and but detected more gene mutations compared to the counselling-directed arm. The ICER indicates a mean cost increase of $7,064 per person for each additional mutation detected.

CONCLUSIONS

: Use of reflex tumor testing of gene panels appears cost effective compared to counselling-directed testing, as long as tumor tests are reliable and do not require routine confirmatory testing.