Early results from a clinical trial appear to confirm that most women with the precancerous breast condition known as ductal carcinoma in situ (DCIS) do not benefit from surgery, as researchers have long suspected.
Women with low-risk DCIS who were monitored with frequent mammograms were no more likely to progress to breast cancer over the next two years than women who had surgery to remove the abnormal cells, according to data presented on Thursday at the San Antonio Breast Cancer Symposium in Texas.
In DCIS - often called stage-zero breast cancer - abnormal cells are present inside the milk ducts, but they do not always evolve to become an invasive type of cancer.
In the U.S. alone, DCIS affects more than 50,000 women each year. Nearly all are treated with surgery, including many who undergo mastectomy.
The 957 women with DCIS in the trial were randomly assigned to undergo surgery or active monitoring. Most participants in both groups also received hormone-blocking therapy.
At two years, the rate of invasive cancer in the surgery group was 5.9%, compared to 4.2% in the active monitoring group, a difference that was not statistically significant, according to a report of the study published in JAMA.
“These early results are provocative and potentially exciting for patients, but we need more long-term follow-up,” study leader Dr. E. Shelley Hwang of the Duke Cancer Institute in Durham, North Carolina said.
“If these results hold up over time, most patients with this type of low-risk disease will have the option of avoiding invasive treatments. That would be a complete change in how we care for these patients and think about this disease.”