Better Prostate Screening Test Needed as Studies Cast Doubt

Two recent studies confirm longstanding concerns about the wisdom of widespread prostate cancer screening using the prostate-specific antigen (PSA) blood test. The two studies found that the popular PSA test save few lives and often lead to risky and unnecessary treatments for large numbers of men.

High levels of PSA, a protein released by prostate cells, suggests that cancer might be present, prompting physicians to order biopsies to determine if cancer exists inside the gland. However, only 25% of those biopsied turn out to have prostate cancer and no clear test is available to distinguish between the faster-growing cancers and the slow ones, resulting in excessive and often unnecessary surgical treatment. Furthermore, about 40% of localized prostate cancers do not secrete high levels of PSA and are missed entirely.

“The reported European and U.S. studies are far from surprising,” says Dr. Amnon Gonenne, President and CEO of MabCure, a diagnostic company that has developed a series of highly specific monoclonal antibodies (MAbs) against melanoma, ovarian carcinoma, and prostate cancer. “The severe limitations of PSA testing stems from the fact that the antigen is not a true cancer marker, but a surrogate for an enlarged or otherwise inflamed prostate.”

Moreover, since the majority of prostate cancers are not life threatening, older men are more likely to die with the disease than from the disease. Therefore, the challenge of diagnosing prostate cancer in its early stage is not merely identifying the presence of cancer, but the ability to determine if the cancer is low risk or aggressive and life threatening. Until prostate cancer-specific markers are identified the diagnostic challenge of identifying men at risk will not be met.

A simple test that can help identify life-threatening prostate cancer is on the horizon thanks to novel monoclonal antibodies (MAbs). MAbs are large, highly complex proteins that recognize other molecules or regions of other molecules known as antigens. MabCure Inc. is creating MAbs for the detection of early-stage cancer (in blood, urine, or other bodily fluids), where the cure rates are greater than 90%.