A new study in JAMA Oncology questions whether the treatment administered to tens of thousands of women who are diagnosed annually with ductal carcinoma in situ (DCIS), a very early-stage breast cancer, actually improves their outcomes.
DCIS—also called Stage Zero breast cancer—is a condition in which abnormal cells build up in the milk duct's lining. Diagnoses of DCIS have increased significantly over the past few decades, and now make up nearly 25% of all cancer diagnoses made via mammography. About 60,000 U.S. women are diagnosed with DCIS annually.
Typical treatment for DCIS consists of getting rid of the small pieces of abnormal cells in the milk duct, just like a surgeon would remove polyps in a colon. But because DCIS has been thought to be a precursor to potentially fatal invasive cancers, women who are diagnosed with DCIS typically receive a lumpectomy, either with or without radiation. Others either have a mastectomy or double mastectomy, out of an abundance of precaution.
However, the study raises doubts about whether such treatments—which can come with physical and emotional costs—actually reduce death rates for women with DCIS.
For the study, researchers analyzed data from a national cancer registry on more than 100,000 women diagnosed with DCIS over a 20-year period. A majority of the patients underwent lumpectomies, while the rest mainly had mastectomies.
The researchers found that the women's likelihood of dying from breast cancer at 20 years post-treatment was 3.3%, regardless of what procedure they chose. That percentage is similar to the average woman's chance of dying from breast cancer, says Laura Esserman, a researcher at the University of California-San Francisco and co-author of an editorial accompanying the study.
However, the breast cancer death rate at 20 years post-diagnosis was higher among black women (7%) and women under age 35 (7.8%), the researchers found.
Findings add to debate
In the editorial accompanying the study, Esserman and her colleague Christina Yau argue that the findings represent a "compelling case" that it is "time for a change" in how DCIS is treated. They write that "much of DCIS should be considered a 'risk factor' for invasive breast cancer and an opportunity for targeted prevention."
And Barnett Kramer, director of the National Cancer Institute's division of cancer prevention, said the study provides "the type of evidence that builds the justification for less morbid treatment."
However, several physicians said that the findings should be interpreted with caution.
Otis Brawley, CMO at the American Cancer Society, says that treatment for DCIS has likely been excessive in some instances. However, both he and Monica Morrow, chief breast cancer surgeon at Memorial Sloan Kettering Cancer Center say that findings are not sufficient to cause physicians to treat DCIS differently than they currently do, with lumpectomies or mastectomies.
In order to better assess the efficacy of treatment, Brawley says researchers would need to conduct a large clinical trial that randomly designates women to mastectomies, lumpectomies, or no treatment for DCIS, and then compares their outcomes (Kolata, New York Times, 8/20 ; Koalata, New York Times, 8/20 ; Johnson/Eunjung Cha, Washington Post, 8/20; Mulcahy , Medscape, 8/20; Tanner, AP/U.S. News & World Report, 8/20).
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