Whether to use adjuvant chemotherapy (CT) is a crucial decision for pts with HR+, HER2− primary BC. The 21-gene Recurrence Score® (RS) assay is validated to predict adjuvant CT benefit and risk of recurrence, using standard RS COV of
Pts with N0, HR+, HER− primary BC and RS results from 2004 to April 2017 were included (data from Genomic Health). Subgroup sizes were determined for RS
Of 609,247 unique RS records analyzed, 513,035 were from the US, 29,248 from EU countries, and 66,964 from RoW. The relative population sizes of RS subgroups were highly consistent across geographical regions. Deviations in percentages for each RS range were within ±3% (Table). Across all regions, >50% of pts had RS
Our analysis revealed highly consistent RS subgroup classifications across geographic regions, mirroring observations from registry studies, suggesting that tumor biology as characterized by RS results does not vary by geography. Our findings therefore support the generalizability of outcomes-study results using standard or custom COV across geographic regions.
Clinical trial identification
Legal entity responsible for the study
M. Verrill: Speaker/advisory/research support: Amgen, Genomic Health, Novartis/GSK, Roche. Speaker/advisor: AstraZeneca, Eisai, Teva. Advisor/research support: Pfizer. Advisor: Merck. C. Fortmann, C. Chao: Employment and stock ownership: Genomic Health. J. Gligorov: Advisor: Eisai, Genomic Health, Novartis, Pfizer, Roche. Research support; Eisai, Roche. All other authors have declared no conflicts of interest.