Risk-Based Screening Misses Many Breast Cancers

A risk-based screening approach for breast cancer among women aged 40 to 49 would miss many cancers, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA).

Researchers from the University of California, San Francisco (UCSF) undertook a retrospective study to determine the prevalence of a very strong family history and extremely dense breast tissue in women in this age group with breast cancer detected on screening mammography.

"Screening recommendations for this age group continue to be debated," researcher Bonnie N. Joe, MD, PhD, associate professor in residence and chief of women’s imaging, UCSF, said in a release. "Recent publications have suggested risk-based screening based on family history and breast density. However, our study shows that this approach would miss a significant percentage of invasive cancers and could potentially be dangerous."

The study included 136 women between the ages of 40 and 49 with breast cancer identified by screening mammography between 1997 and 2012. Patient family history, breast density, type of malignancy, lymph node status, and tumor receptor status were recorded.

The researchers found 194 cases of breast cancer identified by screening, 53% of which were invasive cancer and 47% were ductal carcinoma in situ. Of the patients with invasive disease, 23% had axillary nodal involvement. A very strong family history was absent in 90% and extremely dense breast tissue was absent in 86%. Seventy-eight percent of patients had neither strong family history nor extremely dense breasts, including 79% of the cases of invasive disease.

"Our results show that by exclusively using a risk-based approach to screening mammography, we could potentially miss more than 75 percent of breast cancers in women in their 40s, thereby eliminating most of the survival benefit from screening mammography that has been previously shown in randomized controlled trials," Joe noted in the release.

The researchers concluded that using a risk-based approach to screening mammography would reduce by more than 75% the number of screen-detected cancers.