Model improves prediction of breast cancer risk after benign biopsy
A model that consisted of demographic and histologic features more accurately reflected a woman’s risk for breast cancer after receipt of a benign biopsy than the Breast Cancer Risk Assessment Tool, according to study results.
“Physicians routinely perform biopsies to evaluate concerning findings in the breast, either felt on exam or seen on mammogram, for the presence of a breast cancer,” researcher Amy Degnim, MD, a surgeon at Mayo Clinic in Rochester, Minnesota, said in a press release. “However, about three-quarters of these biopsies prove to be benign and are referred to as benign breast disease.”
Degnim and colleagues evaluated data from women in the Mayo Benign Breast Disease cohort who had a benign biopsy between 1967 and 1991. Researchers created a model based on information garnered from 377 of these women who developed breast cancer, as well as 734 controls who were matched by age and year of benign biopsy.
After evaluating characteristics independently associated with breast cancer risk, the researchers created a benign breast disease-to-breast cancer (BBD-BC) model composed of three pairwise interactions. These pairwise interactions included histologic impression and the combined age at first live birth and number of children; lobular involution and combined age at first live birth and number of children; and lobular involution and sclerosing adenosis/columnar alterations.
Using data from this model development series, researchers calculated a 0.665 concordance statistic for 10-year predictions with the BBD-BC, which was greater than the 0.567 10-year concordance statistic calculated using the Breast Cancer Risk Assessment Tool (BCRAT).
Researchers then validated a model using a population of 378 patients with breast cancer and 728 matched controls from the Mayo Benign Breast Disease cohort. The 10-year concordance statistic with data from this population was 0.629 for the BBD-BC and 0.472 for the BCRAT.
Overall, the BCRAT significantly underpredicted the risk for breast cancer after receipt of a benign breast biopsy (P = .004), whereas the BBD-BC predictions were not statistically different from observed cancers (P = .247).
“Our new model more accurately classifies a woman’s breast cancer risk after a benign biopsy than the BCRAT,” Degnim said. “Since women with benign breast disease are at a higher risk for breast cancer, optimal early detection is extremely important. Ideally, women at increased risk for breast cancer should be identified so that we can offer appropriate surveillance and prevention strategies. Unfortunately, the BCRAT risk prediction model does not provide accurate estimates of risk for these women at the individual level.”
Disclosure: The researchers report no relevant financial disclosures.