In this issue:
BCSC Reports Novel Findings in Breast Cancer Risk & Screening Effectiveness
In its first two years of funding, the "Risk-Based Breast Cancer Screening in Community Settings" (BCSC-P01) program project achieved major advances in understanding breast cancer risk, effectiveness of screening mammography in women at elevated risk, and use of breast magnetic resonance imaging (MRI). The studies summarized below represent the first time these findings have been reported in scientific journals.
In year three, key BCSC research activities include incorporating new variables in the breast cancer risk model, studying policy-relevant breast density research questions, investigating access to and use of advanced breast imaging technologies, and continuing to study the performance of breast screening strategies.
Breast cancer risk
The BCSC found that benign breast diseases and mammographic breast density are independent risk factors for breast cancer. The findings indicated that high breast density with atypical ductal hyperplasia results in high breast cancer risk, but low breast density with benign breast disease does not significantly increase breast cancer risk (Tice et al., 2013).
Effectiveness of screening mammography in high-risk women
The BCSC reported that biennial screening for breast cancer is as beneficial as annual mammography and results in significantly fewer harms (false-positive tests and biopsies) for women who are 50 - 74 years of age and at elevated breast cancer risk because of dense breasts, postmenopausal hormone therapy use, or obesity (Kerlikowske et al., 2013; Dittus et al., 2013). BCSC investigators reported a benefit from annual versus biennial screening mammography for women 40 - 49 years of age who are at elevated breast cancer risk because of extremely dense breasts (Kerlikowske et al., 2013).
MRI performance & utilization
BCSC investigators found that the overall rate of breast MRI (screening, diagnostic evaluation, surveillance) in community practice nearly tripled between 2005 and 2009, increasing from 4.2 to 11.5 exams per 1,000 women. Diagnostic evaluation was the most frequent clinical indication for breast MRI, followed by screening. Compared with the use of screening mammography alone, screening breast MRI was most likely to have been performed in women who were younger (less than 50 years of age), white non-Hispanic, nulliparous (has never given birth), or had any of the following: extremely dense breasts, first-degree relative with breast cancer, personal history of breast cancer, or prior breast biopsy (Wernli et al., 2013).
Current research activities
BCSC research efforts that are underway include:
- Developing the first breast cancer risk model to incorporate single nucleotide polymorphisms (SNPs), sex hormone levels, and quantitative breast density measured on the same women.
- Conducting analyses to guide clinicians and policy makers in response to recent US legislation -- enacted in several states -- requiring that women be notified if they have dense breasts and that having dense breasts may interfere with the effectiveness of a mammogram. Specifically, the BCSC is:
- Ascertaining the levels of breast cancer risk associated with rates of interval cancers (false negatives) or false positives that are high enough to consider supplemental or alternative screening strategies to digital mammography. Risk is being estimated using the BCSC risk calculator and Breast Imaging Reporting and Data System (BI-RADS®) density category.
- Using Cancer Intervention and Surveillance Modeling Network (CISNET) models to determine the potential population impact of offering screening breast ultrasound to women with dense breasts.
- Evaluating the cost-effectiveness of screening women with dense breasts with digital breast tomosynthesis (3-dimensional mammography) compared to screening with digital mammography alone.
- Updating the BCSC risk calculator to improve model discrimination for subgroups of women. The updated model will incorporate two BI-RADS density measures and benign breast disease diagnoses.
- Evaluating whether digital mammography plus computer-aided detection (CAD) improves mammography performance compared to digital mammography alone, according to age and BI-RADS breast density.
- Evaluating performance in community practice of rapidly disseminating advanced imaging screening technologies such as breast MRI, screening ultrasound, and digital breast tomosynthesis.
- Addressing questions of access to and utilization of advanced breast imaging using variables from US Census 2010 linked to women being studied in the BCSC.
For more information
To learn more about the BCSC, please visit http://breastscreening.cancer.gov.