This summary table contains detailed information about research studies. Summary tables are a useful way to look at the science behind many breast cancer guidelines and recommendations. However, to get the most out of the tables, it’s important to understand some key concepts. Learn how to read a research table.
Introduction: Hyperplasia is a benign breast condition where some breast cells divide more quickly than normal.
There are 2 types of hyperplasia: atypical and usual.
Studies show both types of hyperplasia increase the risk of breast cancer, but atypical hyperplasia increases risk more than usual hyperplasia does.
There are special breast cancer screening guidelines for women with atypical hyperplasia.
Learn more about hyperplasia and breast cancer risk.
Learn more about benign breast conditions.
Learn about the strengths and weaknesses of different types of studies.
See how this risk factor compares with other risk factors for breast cancer.
Study selection criteria: Prospective cohort and nested case-control studies with at least 300 cases and meta-analyses.
Table note: Relative risk above 1 indicates increased risk. Relative risk below 1 indicates decreased risk.
Study Population(number of participants)
Relative Risk of Breast Cancer in Women with HyperplasiaCompared to Women without Hyperplasia,RR (95% CI)
Prospective cohort studies
Breast Cancer Surveillance Consortium [1-2]
Estrogen receptor-positive tumors:4.47 (2.88-6.96)
Estrogen receptor-negative tumors:0.20 (0.02-2.51)
Visscher et al. 
Hartmann et al. 
Breast Cancer Prevention Trial-NSABP 
Relative Risk of Breast Cancer in Women with Hyperplasia Compared to Women without Hyperplasia,RR (95% CI)
Nested case-control studies
Dupont et al. 
Kabat et al. 
Nurses' Health Study and Nurses' Health Study II 
Dyrstad et al. 
* Relative risks estimated from standardized incidence ratios.
† Controls were women who had non-proliferative (without fast-growing cells) benign breast disease.
Discover the different ways you can help