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.”
Doctors and patients praised the study and said if the results can be translated into simple testing in the exam room, many thousands of women could be spared painful surgical procedures and radiation treatments.
"It's such a wonderful thing for women who are going through this. I'm just sad it's a little too late for me," said Cynthia Artiga-Faupusa, a San Francisco teacher who was diagnosed with DCIS last year and opted for a double mastectomy. Her mother and grandmother both had breast cancer, and she didn't want to risk developing invasive cancer down the line.
"I know I made the right decision for me," said Artiga-Faupusa, who is 35. "But to have the extra reassurance that it was the right decision, that would have been a huge relief."
From the New York Times:
“Several breast cancer experts not involved in the study said that the findings were an important step toward more personalized cancer treatment, but that they were not likely to change practice any time soon.
“It’s a great study and a good example of how we can decrease overtreatment by identifying markers which can tell us which lesions are the good ones versus which are likely to become invasive and deserve more aggressive treatment,” said Dr. Susan Love, clinical professor of surgery at the David Geffen School of Medicine at the University of California at Los Angeles.
“An accompanying editorial said the study was “thought provoking” and “mystifying” because the “triple positive” biomarker predicted risk for invasive breast cancer but did not predict increased future risk for recurrent D.C.I.S.
“The study is also limited by its size and the fact that the women studied received only lumpectomies. Typically, women with D.C.I.S. get lumpectomy and radiation or mastectomy.
“This is not practice changing,” said Dr. Jennifer Litton, assistant professor in the department of breast medical oncology at the University of Texas M. D. Anderson Cancer Center. “But it’s certainly very exciting to start to give us more clues as to what might be the underlying biology of less aggressive or more aggressive tumors.”
The Journal of the National Cancer Institute article:
http://jnci.oxfordjournals.org/cgi/content/abstract/djq101
The San Francisco Chronicle story:
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/04/28/MNOT1D6D4T.DTL
The New York Times story:
http://www.nytimes.com/2010/04/29/science/29breast.html