Trends in Breast Cancer Rates Among U.S. Women
Author Information
Author(s): Jemal Ahmedin, Ward Elizabeth, Thun Michael J
Primary Institution: American Cancer Society
Hypothesis
The decrease in breast cancer incidence rates may be attributed to reduced use of hormone replacement therapy.
Conclusion
Breast cancer incidence rates have decreased in women aged 45 and older, particularly among those aged 50 to 69, likely due to reduced hormone replacement therapy use.
Supporting Evidence
- Breast cancer incidence rates decreased in all age groups from 45 years and above between 1999 and 2003.
- The sharp decrease in incidence from 2002 to 2003 was largely confined to ER+ tumors.
- No decrease in incidence was observed for larger tumors or advanced-stage disease during the corresponding periods.
Takeaway
The number of women getting breast cancer has gone down, especially for those over 50, because fewer women are using hormone therapy.
Methodology
Joinpoint regression analysis was used to analyze trends in age-adjusted breast cancer rates.
Potential Biases
Potential biases due to the reliance on historical data and the limitations of the SEER database.
Limitations
The study did not account for delayed reporting in analyses by stage, tumor size, or ER/PR status.
Participant Demographics
Women aged 40 and older from the nine oldest SEER cancer registry areas.
Statistical Information
Confidence Interval
95% CI, 0.2% to 7.8%
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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