Harvard Women's Health Watch

Research we're watching: Analysis raises new questions about treating noninvasive breast cancer

The purpose of treating ductal carcinoma in situ (DCIS)—the earliest, noninvasive form of breast cancer (often called "precancer")—is to prevent those lesions from becoming invasive and thereby greatly reduce the risk of dying from breast cancer. As mammography has become more precise, it has detected more DCIS, and more women get treatment with surgery and often radiation as well. An analysis published online by JAMA Oncology on Aug. 20, 2015, adds to increasing questions about the best way to manage DCIS in most women diagnosed with it.

Canadian researchers analyzed 20 years of data from 108,000 women with DCIS in a database maintained by the National Cancer Institute. Most women were treated with lumpectomy, often followed by radiation, or mastectomy. The researchers found that treatment with radiation or mastectomy did not lower the overall breast cancer death rate in women with DCIS. It remained at 3.3%—the average death rate from all breast cancers. However there were some groups—including African American women and women under 40—in whom the death rate was higher (7% to 8%).

An accompanying editorial suggests that pathology techniques to identify cell types that signal more aggres-sive forms of breast cancer could help to identify women who have DCIS that warrants treatment with thera-pies targeted at those specific cancers. It also notes that radiation therapy may not be necessary for most other women because its use isn't associated with a reduced risk of death. The editorial underscores the importance of exploring several options for treatment if you're diagnosed with DCIS.