- Testosterone implants are associated with a reduced incidence of breast cancer, according to 10-year results from the prospective cohort Dayton study.
Why this matters
- For more than 80 years, women with hormone deficiency have been treated with testosterone implants.
- Findings should be reassuring to female testosterone recipients.
- Findings may spur research on testosterone implants for breast cancer prevention.
- A prospective cohort of pre- and postmenopausal women (N=1267) given at least 2 subcutaneous pellet insertions of testosterone (2-2.5 mg/kg starting dose) for hormone deficiency.
- 21.1% of women received testosterone plus anastrozole.
- Breast cancer incidence was studied within 240 days of last testosterone insertion.
- Funding: None.
- 11 cases of breast cancer were observed (vs 18 expected) among recipients of testosterone and testosterone/anastrozole, an incidence rate of 165/100,000 person-years.
- This incidence rate is 39% lower than the age-matched Surveillance Epidemiology and End Results expected incidence rate of 271/100,000 person-years (P<.001>
- The breast cancer incidence rate among recipients was also lower than historical controls.
- Observational design.
- Lack of a matched control group.