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. 2023 Mar 20:58:101901.
doi: 10.1016/j.eclinm.2023.101901. eCollection 2023 Apr.

Extended adjuvant aromatase inhibition after sequential endocrine therapy in postmenopausal women with breast cancer: follow-up analysis of the randomised phase 3 DATA trial

Vivianne C G Tjan-Heijnen  1 , Senna W M Lammers  1 , Sandra M E Geurts  1 , Ingeborg J H Vriens  1 , Astrid C P Swinkels  2 , Carolien H Smorenburg  3 , Maurice J C van der Sangen  4 , Judith R Kroep  5 , Hiltje de Graaf  6 , Aafke H Honkoop  7 , Frans L G Erdkamp  8 , Wilfred K de Roos  9 , Sabine C Linn  3   10 , Alexander L T Imholz  11 ; Dutch Breast Cancer Research Group (BOOG) for the DATA Investigators
Affiliations

Extended adjuvant aromatase inhibition after sequential endocrine therapy in postmenopausal women with breast cancer: follow-up analysis of the randomised phase 3 DATA trial

Vivianne C G Tjan-Heijnen et al. EClinicalMedicine. .

Abstract

Background: The DATA study evaluated the use of two different durations of anastrozole in patients with hormone receptor-positive breast cancer who were disease-free after 2-3 years of tamoxifen. We hereby present the follow-up analysis, which was performed after all patients reached a minimum follow-up of 10 years beyond treatment divergence.

Methods: The open-label, randomised, phase 3 DATA study was performed in 79 hospitals in the Netherlands (ClinicalTrials.gov, number NCT00301457). Postmenopausal women with hormone receptor-positive breast cancer who were disease-free after 2-3 years of adjuvant tamoxifen treatment were assigned to either 3 or 6 years of anastrozole (1 mg orally once a day). Randomisation (1:1) was stratified by hormone receptor status, nodal status, HER2 status, and prior tamoxifen duration. The primary outcome was adapted disease-free survival, defined as disease-free survival from 3 years after randomisation onwards. Adapted overall survival was assessed as a secondary outcome. Analyses were performed according to the intention-to-treat design.

Findings: Between June 28, 2006, and August 10, 2009, 1912 patients were randomly assigned to 3 years (n = 955) or 6 years (n = 957) of anastrozole. Of these, 1660 patients were eligible and disease-free at 3 years after randomisation. The 10-year adapted disease-free survival was 69.2% (95% CI 55.8-72.3) in the 6-year group (n = 827) and 66.0% (95% CI 62.5-69.2) in the 3-year group (n = 833) (hazard ratio (HR) 0.86; 95% CI 0.72-1.01; p = 0.073). The 10-year adapted overall survival was 80.9% (95% CI 77.9-83.5) in the 6-year group and 79.2% (95% CI 76.2-81.9) in the 3-year group (HR 0.93; 95% CI 0.75-1.16; p = 0.53).

Interpretation: Extended aromatase inhibition beyond 5 years of sequential endocrine therapy did not improve the adapted disease-free survival and adapted overall survival of postmenopausal women with hormone receptor-positive breast cancer.

Funding: AstraZeneca.

Keywords: Adjuvant; Aromatase inhibitor; Breast cancer; Endocrine therapy; Extended treatment.

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Conflict of interest statement

VCGT-H reports grants and personal fees from AstraZeneca during the conduct of the study and outside the submitted work; grants and personal fees from Novartis and Lilly; grants from Roche, Pfizer, Daiichi Sankyo, and Gilead outside the submitted work. VCGT-H has a consulting role for AstraZeneca, Lilly, and Novartis. SWML reports grants from AstraZeneca during the conduct of the study; grants from Lilly outside the submitted work. SMEG reports grants from AstraZeneca during the conduct of the study; grants from Roche, Pfizer, Novartis, Lilly, Daiichi Sankyo, and Gilead; personal fees from AstraZeneca outside the submitted work. IJHV reports grants from AstraZeneca during the conduct of the study; grants from Pfizer and Lilly outside the submitted work. ACPS and ALTI report grants from AstraZeneca during the conduct of the study. CHS is chair of the Board of Dutch national breast cancer guidelines. JRK reports grants from AstraZeneca, MSD, Eisai, Lilly, and GSK outside the submitted work. JRK has been a Data Safety Monitoring Board or Advisory Board member for the Alison trial (UMCG) and the TEIPP trial (EMC). AHH reports grants from the Dutch Breast Cancer Research Group during the conduct of the study and outside the submitted work. AHH has been an Advisory Board member for Lilly. AHH received support from Pfizer to attend the ESMO 2022 congress. SCL reports grants from AstraZeneca during the conduct of the study and outside the submitted work; grants from Eurocept Plaza, Roche, Genentech, Gilead Sciences, Tesaro, Novartis, Dutch Cancer Society, ZonMW, A Sister's Hope [Z]aan de Wandel, and Agendia outside the submitted work; consulting fees from AstraZeneca, ERC (EU), and NWO (Dutch Research Council); payment or honoraria from Daiichi Sankyo; other financial support for attending meetings from Daiichi Sankyo, ESMO, ERC (EU), and NWO (Dutch Research Council); non-financial support from Genentech (drug), Roche (drug), Gilead Sciences (drug), Novartis (drug), Agendia (gene expression tests), and AstraZeneca (drug). SCL has a patent (UN23A01/P-EP) pending on a method for assessing homologous recombination deficiency in ovarian cancer cells. SCL is chair of the Trial Steering Committee of the PIONEER trial (Cambridge University) and Member of the Health Council of the Netherlands – Independent scientific advisory body for government and parliament. The other authors have declared no conflicts of interests.

Figures

Fig. 1
Fig. 1
Trial profile.
Fig. 2
Fig. 2
Adapted disease-free survival (A), adapted overall survival (B), adapted breast cancer-free interval (C), and adapted breast cancer-specific mortality (D) in 1660 patients who were disease-free at 3 years after randomisation.
Fig. 3
Fig. 3
Explorative subgroup analyses of adapted disease-free survival comparing 6 years of anastrozole with 3 years of anastrozole.
Fig. 4
Fig. 4
Adapted disease-free survival in (A) patients diagnosed with an oestrogen receptor- and progesterone receptor-positive tumour, and (B) patients diagnosed with an oestrogen receptor- or progesterone receptor-positive tumour.
See this image and copyright information in PMC

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