It is time to rethink the way oncologists in the United States are treating ductal carcinoma in situ (DCIS), particularly in light of recent research suggesting that certain breast cancer rates may be on the rise, says Laura Esserman, MD, MBA, a professor of surgery and radiology at the University of California, San Francisco.
“We all are concerned that we are treating too much DCIS but no one knows how to get off the wheel and do something different,” Esserman said during a presentation at the Miami Breast Cancer Conference on Thursday.
Esserman, who also is director of the Carol Franc Buck Breast Cancer Center and Translational Informatics at UCLA, said that detection of DCIS has increased 500% since mammograms were introduced, and that surgeons in this country alone have removed >60,000 cases of DCIS per year for >10 years.
Yet, she said, the factors that cause DCIS to develop into invasive cancer remain unclear. DCIS, she noted, is heterogeneous, with variation in grade, receptor positivity, frequency of mutations, degree of necrosis, tumor density, and disease extent.
“Have we identified the right precursor lesion?” she asked. “If we want screening to be good, we have to be more thoughtful about what we’re trying to detect.”
Most experts agree that the decline in the incidence of breast cancer rates in 2003 stems from women abandoning hormone replacement therapy after research linked its use to cancer. Nevertheless, Esserman said, even a large drop in invasive cancer does not prove most DCIS is a precursor of invasive cancer.
Esserman said there are 2 important facts of risk: 1) the risk that an invasive cancer will appear in the same region; and 2) the timing of the risk.
“For high-grade lesions, the timing of risk is likely to be within the first 5 years,” she said in her presentation abstract. She said the approach in those cases should be “to study the biology and employ window trials to start screening potential risk-reducing agents.”
However, Esserman suggested lesions with a 20% to 35% risk of progression should be classified as high risk and not as cancer, and should be followed as such. She suggested low-grade DCIS be called “atypia” and that intermediate DCIS be referred to as “ductal intraepithelial neoplasia.”
“If we continue on the same clinical path, we cannot hope to have any type of change,” Esserman said.