July 14, 2011 -- The blood test widely used to detect prostate cancer may prove to be a useful diagnostic tool for breast cancer, a study shows.
Researchers in Taiwan, using a technique they developed, say they were able to detect prostate-specific antigen (PSA) in the blood of women with breast cancer.
PSA levels in these women were more than three times higher than levels in women without breast cancer, suggesting that it could be a useful biomarker for the disease.
The study was small, and the findings need to be confirmed. But they suggest that PSA may be more sensitive and specific than existing biomarkers for detecting breast cancer and predicting its recurrence, researchers say.
The protein known as prostate-specific antigen is not specific to the prostate at all.
PSA is secreted by many organs, including the breast, but at levels that are so low that they are usually undetectable using available detection methods.
In an effort to improve PSA detection, researchers from the National Yang-Ming University and Guang Gung University in Taipei used state-of-the-art fiber optic technology to develop a biosensor capable of detecting the protein in the serum of women with and without breast cancer.
Chin Chou, PhD, and colleagues report that the test's ability to detect PSA and avoid false breast cancer diagnoses is similar to mammogram.
The study appears in the July issue of Analytical Chemistry.
Current biomarkers for breast cancer diagnosis, including cancer antigen (CA) 15-3 or CA27-29, detect metastatic disease in less than half of patients and are not recommended for surveillance of women with known disease, the researchers note.
PSA and Breast Cancer
Stephanie Bernik, MD, who is chief of surgical oncology at New York's Lenox Hill Hospital, says dramatic advances in technology should lead to far more useful biomarkers in the near future.
"A major goal is to be able to rely on these biomarkers to tell us when to begin treatment," she tells WebMD. "I believe this will happen, but I can't say when."
She calls the new research "intriguing" and worthy of follow-up studies to determine if PSA has a role in breast cancer detection and recurrence.
William Chambers of the American Cancer Society agrees, but he warns that the problems that have plagued PSA testing for prostate cancer may also limit its usefulness as a screening tool for breast cancer and other malignancies.
Chambers directs the division of clinical cancer research and immunology at the American Cancer Society.
In recent years it has become clear that PSA testing may sometimes lead to overdiagnosis and overtreatment of prostate cancer. "There was a lot of excitement in the early days about the detection of prostate cancer using PSA, but it has certainly not turned out to be the screening tool that we had hoped it would be" he tells WebMD.