Real-world analysis of clinical and economic impact of 21-gene recurrence score (RS) testing in early-stage breast cancer (ESBC) in Ireland.

Abstract

540 Background: Treatment of hormone receptor positive (HR+) ESBC is evolving. The use of chemotherapy (CT) is declining with use of the 21-gene RS assay. This validated tool predicts the likelihood of adjuvant CT benefit in HR+ ESBC. Results from the TAILOR-x study suggest up to 70% of HR+ node negative ESBC patients (pts) may avoid CT with RS ≤25. Our objectives were to assess the clinical and economic impact of RS testing on treatment decisions using real-world data. Methods: From October 2011 to February 2019, a retrospective, cross-sectional observational study was conducted of HR+ node negative ESBC pts who had RS testing in Ireland. A survey of Irish breast medical oncologists provided the assumption for the decision impact analysis that grade (G) 1 pts would not receive CT pre RS testing and G2/3 pts would receive CT. Using TAILOR-x results, pts were classified low risk (RS ≤ 25) and high risk (RS > 25). Data was collected via electronic patient records. Descriptive statistics were used. Cost data was obtained via the National Healthcare Pricing Regulatory Authority. The economic analysis was adjusted for changing treatment and assay costs over the study period. Results: 963pts were identified. Mean age 56 years. Mean tumour size 1.87cm. 114 (11.8%), 636(66%), 211(22%), 2(0.2%) pts had G1, G2, G3 and unknown G respectively (resp). 797pts (82.8%) had low RS, 159 (16.5%) had high RS, and 7pts(0.7%) unknown RS. 251pts(26%) were aged < 51 at diagnosis. Of these, 45(17.9%), 145(57.8%), 58(23%), 3(1.2) had G1, G2, G3 and unknown G resp. 208pts(82.9%) had RS ≤ 25, 39pts(15.5%) had RS > 25 and 4pts(1.6%) unknown RS. In the RS ≤ 25 group, 111pts(44%) had RS 0-15, 59(23.5%) had RS16-20, and 38(15.1%) had RS21-25. Post RS testing 595pts(61.8%) had a change in CT decision; 586 changed to hormone therapy (HT) alone, and 9 from HT to CT. In total, 227pts(23.5%) received CT, and 3pts(0.3%) declined. Of pts treated with CT; 9(4%) had RS 0-15, 89(39.2%) had RS16-25, 129(56.8%) had RS > 25. The most common CT regimen was docetaxel and cyclophosphamide(TC), administered to 121pts(53%). RS assay use achieved a 69% change in treatment decision among G2/3 pts and a net 61% reduction in CT use. This resulted in savings of over €4 million in treatment costs. Deducting the assay cost, net savings of over one million euro was achieved. Conclusions: Ireland was the first public healthcare system to approve reimbursement for RS testing. Over the 8 year period of the study, a net 61% reduction in CT use in Irish pts with HR+ ESBC was achieved with conservative net savings of over €1,000,000.