February 15, 2006
Treatment of milk-duct growths requires more than surgery, study finds
Julia Wong, MD
Surgery alone does not adequately lower the chances of relapse for women with small, early-stage growths in the milk ducts of the breast, a new study by Dana-Farber/Harvard Cancer Center researchers has found.
The study sought to determine whether women with a condition known as ductal carcinoma in situ (DCIS) - in which abnormal cells appear in the milk ducts, but which may later invade adjacent tissue - can sufficiently protect themselves from a recurrence solely by undergoing surgery to remove the DCIS and a sizable margin of surrounding tissue. Standard treatment for the condition involves surgery followed by radiation therapy and, frequently, a prescription for the drug tamoxifen.
"Improvements in mammographic screening and microscopic examination of abnormal breast cells have given us the ability to detect smaller and smaller areas of DCIS," says the study's lead author, Julia Wong, MD, of Radiation Oncology at Dana-Farber. "We know from previous studies that breast-conserving surgery followed by radiation therapy reduces recurrence rates by 50 to 60 percent. But radiation therapy hasn't been shown to improve survival rates; it's also time-consuming and can have some undesirable side effects. As a result, there has been an interest in identifying patients with small DCIS growths who might be effectively treated with surgery alone."
DCIS is diagnosed in approximately 50,000 women annually in the United States, a number that has risen in recent years due to improvements in screening technology. If treated while confined to the milk ducts, the disease is almost always curable.
The new study, to be published in the March 1 issue of the Journal of Clinical Oncology, but available online now at www.jco.org/cgi/content/abstract/JCO.2005.02.9975v1, involved 158 women who had been diagnosed with small, early-stage DCIS growths. All were treated with surgery in which doctors removed the abnormal tissue and a margin of healthy tissue at least 1 centimeter wide.
Thirteen patients had abnormal cells reappear at the original site 7 to 63 months after surgery. In nine of those patients, the abnormal cells were confined to the milk ducts; in four of them, the cells had begun invading surrounding tissue. None of the patients in this group was found to have abnormal cells in the lymph nodes, indicating that the disease had not spread to other parts of the body.
The recurrence rate equals 12 percent over a five-year period. Faced with such a large percentage of recurrent disease, investigators stopped enrolling new patients in the study.
"Our findings suggest that surgical removal of DCIS tissue, even with a margin of at least a centimeter, isn't enough to provide a predictably low recurrence rate for women with small, early-stage DCIS," Wong states. "For now, it remains unclear how best to identify patients with DCIS who have a low risk of recurrence if treated with surgery alone. Future studies, possibly using molecular techniques, may hold the answers."
The study's senior author was Barbara Smith, MD, director of the Gillette Center for Breast Cancer at Massachusetts General Hospital (MGH). Co-authors included Michele Gadd, MD, Rebecca Gelman, PhD, and Jay Harris, MD, of Dana-Farber, and associates at Brigham and Women's Hospital, MGH, Beth Israel Deaconess Medical Center, and Harvard Medical School.
