What to do about the non-invasive breast lesions called ductal carcinoma in situ, or "stage zero" cancer, is one of the hottest debates in breast cancer care.
Because of more widespread screening, more and more women are being diagnosed with DCIS. The condition now makes up 20 percent of new breast cancer cases, according to the American Cancer Society.
DCIS doesn't always progress to invasive breast cancer, which is the life-threatening kind. In fact, some physicians and researchers, including a working group convened by the National Cancer Institute, say it's not accurate to call DCIS a form of cancer at all, and that the terminology is contributing to overly aggressive treatment.
"We are certainly overtreating this disease, but we haven't figured out who can get less treatment, no treatment or active surveillance," says Mehra Golshan, a breast surgeon at Brigham and Women's Hospital in Boston. Surgery (lumpectomy and in some cases mastectomy) is the standard of care, but a study by Golshan and his colleagues may support some women's decision to skip the surgery, which comes with physical, emotional and financial costs.
The study, published Wednesday in JAMA Surgery, relied on a National Cancer Institute registry covering 57,222 cases of DCIS in women treated in nine U.S. states between 1988 and 2011. The researchers looked at what happened to women who had surgery and to the small minority of those who didn't. They found that for women whose DCIS was classified as low-grade by a pathologist looking at the cells under the microscope, surgery didn't offer a significant survival advantage over 10 years.
For the women who had cells that were closer on the continuum to invasive cancer — those with intermediate- or high-grade DCIS — surgery did provide a significant benefit. After 10 years, 98.6 percent of women with intermediate-grade DCIS and who had surgery had survived breast cancer, compared to 94.6 percent of women who didn't have surgery. And with high-grade DCIS, 98.4 percent of those who had surgery survived, compared to 90.5 percent of those who didn't.
This study relied on the historical data available in a registry and can't tell us why some women didn't get surgery. (For example, some might have been too sick to tolerate it.) There may have been other differences between those who opted for surgery and those who did not that affected the results. So the researchers can't say for sure that women with low-grade DCIS should not have surgery. There are randomized clinical trials comparing active monitoring to surgery for lower-risk DCIS going on in Europe that may help answer the question.
A commentary accompanying the study says that molecular markers being developed are more promising than the cell grading system for figuring out who will and won't benefit from surgery. That may be true, but those tests aren't yet available and will cost much more, says Golshan, whereas the cell pathology reports are already standard.
For now, most doctors will still recommend surgery. But this research represents "a first step in trying to tailor therapy to be in line with an individual patient's disease," says Golshan. He notes that women are already making a decision one way or the other. These results may make them and their physicians more comfortable with the idea of initially foregoing surgery for careful monitoring and possibly hormone therapy to block estrogen from fueling the growth of the abnormal cells.