New research from the University of California at San Francisco may ultimately save many women with the earliest form of breast cancer from making the decision to have a preventive mastectomy or double mastectomy.
The study, published in today’s Journal of the National Cancer Institute, followed 1,162 women for eight years who had been diagnosed with ductal carcinoma in situ, the most common type of noninvasive breast cancer and one in which the risky cells are contained within the milk ducts. All the women had had lumpectomies, a surgical procedure where a lump is removed from the breast. The researchers found that by studying the tissue for certain biological markers, they could determine which women were more likely to develop invasive cancer later.
"Many people are diagnosed with these pre-malignancies and become alarmed. The problem is that only 1 in 10 cases is going to be associated with future invasive cancer," said Thea Tlsty, a pathology professor at UCSF and a lead author of the study. "Hopefully, we can start stratifying risks, and women and their clinicians can start to choose the appropriate therapy. Why have a complete mastectomy if you don't need to?"
From the San Francisco Chronicle:
“[Researchers] found that women who had high levels of three types of biomarkers were more likely to develop invasive cancer than those who had low levels. The highest risk group had a 20 percent chance of developing cancer in eight years; the lowest risk, only a 4 percent chance. About 28 percent of women fell into the highest risk category.
“Women who had been diagnosed with DCIS through a physical exam, by finding a lump in their breast, also were more likely to develop invasive cancer than those who were diagnosed with a mammogram. Researchers said that wasn't surprising, because mammograms are more sensitive and may catch small, pre-cancerous lesions that won't ever become a problem. Lumps found during exams usually are more advanced.”