Specialty group aims to make sense of breast density notification laws

The California Breast Density Information Group (CBDIG), a team of California-based breast imagers and breast cancer risk specialists, has developed a website offering guidance on breast density notification laws.

To help launch the project, members of CBDIG published a special report online Sept. 10 in Radiology laying out issues that practitioners are likely to encounter and reviewing some of the background on breast density laws.

“Breast density notification legislation is becoming increasingly prevalent. The impact of these laws is far reaching, and radiologists should take a proactive role in assessing the need for potential change in their practices and in translating currently available outcomes data into information for referring clinicians and patients that can be easily understood and accessed,” wrote Jafi A. Lipson, MD, of Stanford University School of Medicine in Stanford, Calif., and colleagues.

The group acknowledged that mammography is considered the single best modality for population-based screening, though its sensitivity is reduced up to 20 percent in patients with dense breasts. Approximately half of women undergoing screening mammography are classified as having either “heterogeneously dense” or “extremely dense” breasts.

While the main issue is the reduction in mammography sensitivity due to cancers being masked by surrounding breast tissue, risks levels are also slightly elevated in women with dense breasts. The 40 percent of women with heterogeneously dense breasts experience 1.2 times greater than average risk of cancer, and the 10 percent of women with extremely dense breasts have approximately 2.1 times the risk.  

Nine states have responded to this information by adopting laws requiring notification of patients and referring physicians in cases where the interpreting radiologist determines that the pattern of fibroglandular tissue on a patient’s mammogram is considered dense. California’s notification requirement took effect on April 1.

CBDIG wrote that the laws will encourage supplemental screening, such as with MRI and ultrasound, and that in California alone, up to two million women could receive a notification of dense breasts each year.

“While additional screening for women with extremely dense breasts could prove beneficial, supplemental screening of the approximately 40 percent of California women with heterogeneously dense breasts would result in very substantial additional cost to the healthcare system,” Lipson said in a press release. “There also is concern that the increased use of supplementary screening will ultimately expose some patients to more harm, in the form of false-positive results, than good.”

In order to address this challenge, CBDIG recommended an individualized risk-based approach to decision-making, as women with a high risk of breast cancer, such as those with BRCA genetic mutation, are more likely to benefit from supplemental screening. Women not at high risk will see less benefit, while remaining at risk for the potential harms of overdiagnosis.

“In our era of patient-centered care and personalized medicine, breast density notification legislation provides an opportunity for radiologists to engage with referring clinicians and patients,” wrote CBDIG.

More information from CBDIG on breast density legislation is available at www.breastdensity.info.