Association between reproductive history, breast cancer subtype, and survival in premenopausal women

• Published in: Medicina clinica Vol. 162; no. 6; p. 265
• Main Authors: Bernal-Gómez, Marta, Núñez-Álvarez, Violeta, Lluch-Gómez, Jaime, de la Torre-Hita, Carlos, Campini-Bermejo, Alicia, Perdomo-Zaldívar, Eduardo, Rodríguez-Pérez, Lourdes, Calvete-Candenas, Julio, Benítez-Rodríguez, Encarnación, Baena-Cañada, José Manuel
• Format: Journal Article
• Language: English; Spanish
• Published: Spain 22.03.2024
• Subjects: Breast cancer subtype; Reproductive history; Subtipo de cáncer de mama; Historia reproductiva; Breast cancer survival; Supervivencia
• ISSN: 1578-8989
• DOI: 10.1016/j.medcli.2023.10.015

Reproductive history influences breast cancer risk. We analysed its association with tumour subtype and survival in premenopausal women. Retrospective, observational study of premenopausal women with stage I-III breast carcinoma in the last 20 years. Review of reproductive history, clinical data, and treatments in health records. In 661 premenopausal women (32.40% of 1377 total cases), median age was 47 years (19-53), menarche 12 (7-17), first delivery 28 (16-41) and number of deliveries 2 (0-9). One hundred and eleven (18.20%) were nulliparous. Three hundred and fifty-nine (58.80%) used natural lactation, with a median duration of 6 months. Anovulatory drugs were used by 271 (44.40%), with a median duration of 36 months. Associations were found between menarche <10 years and lower risk of luminal subtype (OR: 0.52, 95% CI: 0.28-0.94; P=.03), between menarche >11 years and lower risk of HER2 subtype (OR: 0.50, 95% CI: 0.26-0.97; P=.04) and between first birth >30 years and lower risk of triple negative subtype (OR: 0.40, 95% CI: 0.17-0.93; P=.03). The 20-year overall and disease-free survival probabilities were 0.80 (95% CI: 0.71-0.90) and 0.72 (95% CI: 0.64-0.79) respectively. Patients with ≥1 delivery had better overall survival than nulliparous patients (HR: 0.51, 95% CI: 0.27-0.96, P=.04). The findings suggest an association between age at menarche and age at first delivery and breast cancer subtype. Nulliparity is associated with worse survival.