Author Interviews, Breast Cancer, JAMA, Mammograms, UC Davis / 21.10.2015
Should Breast Cancer Screening Be Different For Pre vs Post Menopausal Women?
MedicalResearch.com Interview with:
Diana L. Miglioretti, PhD
Dean's Professor in Biostatistics
Department of Public Health Sciences
UC Davis School of Medicine
Davis, CA 95616
Medical Research: What is the background for this study? What are the main findings?
Dr. Miglioretti: Screening mammography intervals remain under debate in the United States. The US Preventive Services Task Force recommends biennial (every other year) screening, whereas other organizations recommend annual screening. To help inform their updated screening guidelines, the American Cancer Society guideline development group requested that the US Breast Cancer Surveillance Consortium conduct a study comparing cancer outcomes among women screened annually vs. biennially. Prior studies conducted by the consortium used wide intervals for defining annual and biennial mammograms. We wanted to evaluate cancer outcomes for women who more closely adhere to screening intervals. Our goal was to determine if women diagnosed with cancer following biennial screening have tumors with less favorable prognostic characteristics compared to women diagnosed after annual screening. We evaluated outcomes separately by age and by menopausal status because evidence suggests that younger women and premenopausal women may have more aggressive tumors and thus may benefit from more frequent screening.
We found from this study that premenopausal women diagnosed with invasive breast cancer following biennial versus annual screening mammography were more likely to have tumors with less-favorable prognostic characteristics (e.g., later stage, larger size). For example, women with an invasive breast cancer diagnosed after a biennial screen had a 28% increased risk of a stage IIB or higher tumor, a 21% increased risk of being diagnosed with a tumor >15 mm, and an 11% higher risk of being diagnosed with a tumor with any less-favorable prognostic characteristic compared women diagnosed with breast cancer following an annual mammogram.
In contrast, we found postmenopausal women not using hormone therapy and women 50 years of age or older had similar proportions of tumors with less-favorable prognostic characteristics regardless of screening interval. Relative risk estimates were close to one with no significant differences between biennial and annual screeners.
Among postmenopausal women using hormone therapy at the time of the mammogram and women age 40-49, results were less clear. Relative risk estimates for biennial versus annual screeners were consistently above one, but were not as large as for premenopausal women and were not statistically significant.
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