Early results from a clinical trial appear to confirm that most women with the precancerous breast condition known as ductal carcinoma in situ do not benefit from surgery, as researchers have long suspected.
Women with low-risk ductal carcinoma in situ (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 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 clearly need more long-term follow-up,” study leader E. Shelley Hwang, MD, of the Duke Cancer Institute in Durham, North Carolina said in a statement.
“If these results hold up over time, most patients who have 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.”
Ibrance extends control of type of breast cancer 15 months
Pfizer’s Ibrance helped keep metastatic breast cancer under control for significantly longer than usual in patients with a certain type of tumor, according to trial results presented on Thursday at the San Antonio meeting.
The nearly 500 patients all had advanced disease from so-called hormone receptor, or HR-positive, human epidermal growth factor receptor 2 - HER2-positive - tumors.
The median time to disease progression was 44.3 months with Ibrance on top of the usual treatments. Those who received only standard treatment went 29.1 months before the cancer began to worsen.
“These results support the potential of this maintenance treatment to slow disease progression and improve clinical outcomes in this patient population,” said Dr. Otto Metzger, an oncologist at the Dana-Farber Cancer Institute in Boston, who led the trial.
Approximately 10% of all breast cancers are HR- and HER2-positive. They are sometimes referred to as double-positive or triple-positive breast cancer. The tumor cells have surface proteins, or receptors, that bind to estrogen or progesterone, or both, as well as a surface receptor that binds to HER2, a protein that controls cell growth.
Ibrance was the first drug to act against the CDK4 and CDK6 enzymes, which play important roles in cell division, when it was approved in 2015.
