Breast cancer mortality after hormone exposure
Author Information
Author(s): Wansu Chen, David B. Petitti, Angela M. Geiger
Primary Institution: Kaiser Permanente Southern California
Hypothesis
This study explored survival after exposure to oestrogen or oestrogen plus progestin at or in the year prior to breast cancer diagnosis.
Conclusion
Patients diagnosed with breast cancer while exposed to oestrogen plus progestin had a lower risk of death from all causes and from breast cancer compared to nonusers.
Supporting Evidence
- Oestrogen plus progestin users had lower all-cause mortality compared to nonusers.
- Oestrogen users did not experience a significant survival benefit.
- Patients with stage I cancer showed a nearly 50% risk reduction in mortality with oestrogen plus progestin.
Takeaway
Women who took a combination of oestrogen and progestin before being diagnosed with breast cancer lived longer than those who didn't take hormones.
Methodology
A retrospective, computer record-linkage, cohort study using data from a large health maintenance organization.
Potential Biases
Potential bias due to healthier hormone users receiving better treatments and the healthy user effect.
Limitations
The study relied on prescription data which may not reflect actual drug consumption, and there were limitations in attributing cause of death.
Participant Demographics
Patients diagnosed with invasive breast cancer between 1993 and 1998, with a mean age at diagnosis of approximately 61 years.
Statistical Information
P-Value
0.010
Confidence Interval
95% CI 0.48–0.99 for stage I; 95% CI 0.39–0.73 for stage II
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
Want to read the original?
Access the complete publication on the publisher's website