JAMA Oncol
Breast cancer risk of hormonal contraceptives varies by progestin component
Study details: This Swedish nationwide cohort study analyzed 2.1 million females aged 13 to 49 years from 2006 to 2019 using national prescription and cancer registries to assess breast cancer risk associated with different hormonal contraceptive formulations and routes of administration. Time-dependent Cox regression estimated hazard ratios (HRs) for invasive and in situ breast cancer.
Results: Ever use of any hormonal contraceptive was associated with a 24% increased breast cancer risk (HR, 1.24; 95% confidence interval [CI], 1.20–1.28), equating to one extra case per ~7,752 users (95% CI, 5,350-14,070) annually. Both combined (HR, 1.12) and progestin-only (HR, 1.21) formulations were associated with risk. Oral desogestrel-only (HR, 1.18) and desogestrel-combined pills (HR, 1.19), as well as etonogestrel implants (HR, 1.22), carried the highest risk. Levonorgestrel-containing pills (HR, 1.09) and intrauterine systems (HR, 1.13) had lower risk, while medroxyprogesterone acetate injections and drospirenone-combined pills showed no significant increase.
Clinical impact: Not all hormonal contraceptives confer equal breast cancer risk. Formulation-specific counseling—especially avoiding long-term desogestrel use in high-risk patients—may help optimize safety while preserving contraceptive benefits.
Source:
Hadizadeh F, et al. (2025, October 30). JAMA Oncol. Hormonal Contraceptive Formulations and Breast Cancer Risk in Adolescents and Premenopausal Women. https://pubmed.ncbi.nlm.nih.gov/41165687/