Anastrozole Dose Escalation for Optimal Estrogen Suppression in Postmenopausal Early-Stage Breast Cancer: A Prospective Trial.
Clin Cancer Res
; 30(15): 3147-3156, 2024 Aug 01.
Article
en En
| MEDLINE
| ID: mdl-38752717
ABSTRACT
PURPOSE:
We previously reported that postmenopausal women with estrogen receptor-α-positive breast cancer receiving adjuvant anastrozole 1 mg/day (ANA1) with estrone (E1) ≥1.3 pg/mL and estradiol (E2) ≥0.5 pg/mL [inadequate estrogen suppression (IES)] had a threefold increased risk of a breast cancer event. The objective of this study was to determine if increasing anastrozole to 10 mg/day (ANA10) could result in adequate estrogen suppression (AES E1 <1.3 pg/mL and/or E2 <0.5 pg/mL) among those with IES on ANA1. PATIENTS ANDMETHODS:
Postmenopausal women with estrogen receptor-α-positive breast cancer planning to receive adjuvant ANA1 were eligible. E1 and E2 were assessed pre- and post-8 to 10 weeks of ANA1. Those with IES were switched to 8- to 10-week cycles of ANA10 followed by letrozole 2.5 mg/day. E1 and E2 were assessed after each cycle. Anastrozole concentrations were measured post-ANA1 and post-ANA10. Primary analyses included patients who documented taking at least 80% of the planned treatment (adherent cohort).RESULTS:
In total, 132 (84.6%) of 156 eligible patients were ANA1 adherent. IES occurred in 40 (30.3%) adherent patients. Twenty-five (78.1%) of 32 patients who began ANA10 were adherent, and AES was achieved in 19 (76.0%; 90% confidence interval, 58.1%-89.0%) patients. Anastrozole concentrations post-ANA1 and post-ANA10 did not differ by estrogen suppression status among adherent patients. AES was maintained/attained in 21 (91.3%) of 23 letrozole-adherent patients.CONCLUSIONS:
Approximately 30% of ANA1-adherent patients had IES. Among those who switched to ANA10 and were adherent, 76% had AES. Further studies are required to validate emerging data that ANA1 results in IES for some patients and to determine the clinical benefit of switching to ANA10 or an alternative aromatase inhibitor.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Triazoles
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Neoplasias de la Mama
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Posmenopausia
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Anastrozol
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Nitrilos
Límite:
Aged
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Female
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Humans
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Middle aged
Idioma:
En
Revista:
Clin Cancer Res
Asunto de la revista:
NEOPLASIAS
Año:
2024
Tipo del documento:
Article