Hydralazine and breast cancer

Area of Science:

• Oncology
• Pharmacology
• Epidemiology

Background:

• Hydralazine is a common antihypertensive medication.
• Concerns exist regarding its metabolite, hydrazine, a known carcinogen in animal studies.
• The relationship between hydralazine use and human breast cancer risk requires investigation.

Purpose of the Study:

• To evaluate the association between hydralazine use and the risk of developing breast cancer in women.
• To determine if hydralazine use is a risk factor for human breast cancer.

Main Methods:

• A case-control study involving 3,419 women with breast cancer and 3,219 hospital controls.
• Data collected through interviews in U.S. and Canadian hospitals.
• Multivariate analysis adjusted for breast cancer risk factors and other antihypertensive/diuretic use.

Main Results:

• 1.4% of breast cancer cases and 1.2% of controls reported hydralazine use.
• The relative risk (RR) for hydralazine use (first used ≥18 months prior) was 0.9 (95% CI, 0.5-1.7).
• RR estimates for use duration (≥1 year, up to 5+ years) and stratified by risk factors remained close to 1.0.

Conclusions:

• Hydralazine use does not appear to elevate short-term breast cancer risk in humans.
• The study could not assess potential risks associated with very long-term hydralazine use or long latent intervals.