Breast Fluid May Predict Cancer Risk

December 04, 2001
News Office: Eve Harris (415) 502-6397

Easily obtained breast fluid samples have been shown in a UCSF study to help predict who is at increased risk for breast cancer.

Researchers used a modified breast pump -- a simple, non-invasive technique that can be performed in doctors' offices -- to obtain breast fluid which was then evaluated for cellular abnormalities.

Nipple aspirates of breast fluid have been collected since the early 1970s at UCSF. In an initial study from 1972 through 1980 this technique was used to collect, analyze and classify samples of fluid from the breasts of 4,046 non-lactating women in the San Francisco Bay Area. These women were followed through 1991 to determine which of them developed breast cancer. The results of that earlier study showed that women with abnormal cells in breast fluids were more likely to develop breast cancer.

The UCSF study published Dec. 4 in the Journal of the National Cancer Institute extends the follow up in the original study group and includes a second group of 3,271 participants between 1981 and 1991. Both groups were followed through March of 1999 to identify which women later developed breast cancer.

Consistent with earlier studies, not all participants yielded breast fluid, but the women whose fluid contained normal cells were 30 percent more likely to develop cancer than women from whom no fluid was obtained.

Furthermore, analysis of cells in the fluid provided an even more detailed risk assessment. Women who produced fluid with abnormal cells were twice as likely to develop breast cancer as women from whom no fluid could be obtained and were 60 percent more likely to develop breast cancer than women with normal cells in their fluid.

According to the study's primary author Margaret R. Wrensch, UCSF professor of epidemiology and biostatistics, the major advantage of using a simple breast pump to obtain specimens is that the technique is non-invasive, and so involves very minimal or no risk to the woman. "Research is still needed to find other markers for cancerous and pre-malignant cells that can be detected with even simpler tests than the cytologic analyses performed for this study. Such future studies might yield more specific information about a woman's breast cancer risks," said Wrensch. "While other methods and markers are being discovered, we hope that our current findings will encourage increasing numbers of clinicians and researchers to use this simple technique."

Breast cancer is the most common malignancy in women. The lifetime risk of a woman in the United States developing breast cancer is 1 in 8. The risk increases with advancing age -- 1 in 54 by age 50 and 1 in 23 by age 60 (National Cancer Institute, 2000). According to the American Cancer Society, an estimated 192,000 new cases of invasive breast cancer and approximately 40,600 breast cancer deaths are expected in the U.S. in 2001.

The study was funded by the National Cancer Institute and the California Breast Cancer Research Program.

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