Adjuvant chemotherapy in T1a/bN0 breast cancer with a high 21-gene recurrence score (>25): A 10-year follow-up in a real-world cohort Journal Article


Authors: Katz, D.; Feldhamer, I.; Wolff-Sagy, Y.; Goldvaser, H.; Hammerman, A.; Goldstein, D. A.
Article Title: Adjuvant chemotherapy in T1a/bN0 breast cancer with a high 21-gene recurrence score (>25): A 10-year follow-up in a real-world cohort
Abstract: Background In ER + /HER2- early breast cancer (BC), 21-Gene Recurrence Score (RS) > 25 indicates high-risk of distant-recurrence and predicts benefit from adjuvant chemotherapy (aCT) regardless of tumor-size. However, T1a/b (<= 1 cm) node-negative (N0) tumors, regarded as of low risk of recurrence, were under-represented in the RS trials. We therefore aimed to investigate the benefit of aCT in patients with T1a/bN0 BC, RS > 25, where clinical and genomic risk indicators are discordant. Methods This retrospective observational cohort study utilized Israel's national Oncotest database to identify Clalit Health Services (CHS) members, diagnosed with T1a/bN0 HR + /HER2- BC, who underwent RS testing between February 2006, and December 2019. Patients with RS > 25 who received aCT were matched 1:1 by propensity-scoring to similar patients receiving no aCT. Invasive disease-free survival (iDFS) and distant recurrence were the study endpoints. Patient demographic and clinical data were obtained from CHS's centralized database. Kaplan--Meier analysis with log-rank testing was used for comparing outcomes. Results During the study period, high-risk RS result (> 25) was identified in 156/9858 patients of the study cohort. aCT was administered to 74 (47.4%) and median follow-up was 121 months. Within the 148 matched-cases, eighteen iDFS-events occurred, nine (12.1%) in each group (chi(2) = 0.72, p = 0.39). Four (5.4%) of the aCT treated and three (4.0%) of the untreated patients were diagnosed with distant recurrence (chi(2) = 0.22, p = 0.64). Conclusions In this study cohort, patients with T1a/bN0 BC, RS > 25 that received aCT, did not have improved outcomes and the 21-Gene RS > 25 was not found to be predictive, possibly due to the low number of events observed.
Keywords: chemotherapy; breast cancer; assay; expression; clinical-outcomes; adjuvant; aid; treatment decisions; 70-gene signature; oncotypedx (c); t1/bn0
Journal Title: Breast Cancer
Volume: 32
Issue: 2
ISSN: 1340-6868
Publisher: Springer Japan KK  
Date Published: 2025-03-01
Start Page: 286
End Page: 291
Language: English
ACCESSION: WOS:001366238100001
DOI: 10.1007/s12282-024-01652-9
PROVIDER: wos
PMCID: PMC11842534
PUBMED: 39602054
Notes: Article -- Source: Wos
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