Outcomes of single versus double hormone receptor-positive breast cancer. A GEICAM/9906 sub-study.
BACKGROUND
Retrospective data suggest better outcomes for patients with double hormonal receptor (oestrogen [ER] and progesterone receptor [PgR])-positive (dHR+) early breast cancer, compared with single hormonal receptor-positive, sHR+, (ER+/PgR- or ER-/PgR+) disease. Here, we evaluate the classification according to intrinsic subtypes and clinical outcomes of sHR+ versus dHR+ in HER2-negative breast cancer patients enrolled in GEICAM/9906 study (NCT00129922).


METHODS
Archival tumours were retrieved retrospectively for the analysis of ER, PgR and HER2 status and classified into intrinsic subtypes using the PAM50 gene expression assay. Disease-free survival (DFS) and overall survival (OS) were explored using a Cox proportional hazard analysis.


RESULTS
Data on intrinsic subtypes were available in 571 (50%) patients with ER+ and/or PR+, and HER2-negative primary tumours. The incidence of luminal A and luminal B subtypes were 52%/36% in dHR+ tumours (ER+/PgR+), and 15%/58% in ER+/PgR-tumours. ER-/PgR+ tumours were mainly luminal A (52%). Compared with ER+/PgR+ patients, DFS was similar in ER-/PgR+ (hazard ratio [HR] 1.15, 95% confidence interval [CI] 0.57-2.34, p = 0.70) but worse in ER+/PgR- patients (HR 1.60, 95% CI 1.12-2.28, p < 0.01). Similar results were observed for OS (HR 1.50, p = 0.30 and HR 1.86, p < 0.01, respectively).


CONCLUSIONS
The ER+/PgR- group is characterised by higher proliferation and worse outcomes. In spite of the ER-/PgR+ subgroup resembles ER+/PgR+ disease in terms of molecular subtypes and outcomes, the small number of patients in this subgroup prevents from drawing any conclusions.


TRIAL REGISTRATION
EudraCT: 2005-003108-12 (retrospectively registered 28/06/2005). CLINICALTRIALS.


GOV IDENTIFIER
NCT00129922 (retrospectively registered 10/08/2005).
['Ethier|J L|JL|', 'Ocaña|A|A|', 'Rodríguez Lescure|A|A|', 'Ruíz|A|A|', 'Alba|E|E|', 'Calvo|L|L|', 'Ruíz-Borrego|M|M|', 'Santaballa|A|A|', 'Rodríguez|C A|CA|', 'Crespo|C|C|', 'Ramos|M|M|', 'Gracia Marco|J|J|', 'Lluch|A|A|', 'Álvarez|I|I|', 'Casas|M|M|', 'Sánchez-Aragó|M|M|', 'Carrasco|E|E|', 'Caballero|R|R|', 'Amir|E|E|', 'Martin|M|M|']
D000328:Adult D000368:Aged D000971:Antineoplastic Combined Chemotherapy Protocols D001943:Breast Neoplasms D017326:Clinical Trials, Phase III as Topic D003520:Cyclophosphamide D018572:Disease-Free Survival D015251:Epirubicin D005260:Female D005472:Fluorouracil D006801:Humans D008875:Middle Aged D017239:Paclitaxel D016016:Proportional Hazards Models D016032:Randomized Controlled Trials as Topic D011960:Receptors, Estrogen D011980:Receptors, Progesterone D012189:Retrospective Studies D059467:Transcriptome
Breast cancer Intrinsic subtypes PAM50 Hormone receptor positive Single receptor positive