PSA Measurements a Poor Predictor of Prostate Cancer in Overweight and Obese Men: Presented at ASCO By Cameron Johnston A very high body mass index (BMI) can be a confounding factor when evaluating a man's results from the prostate specific antigen (PSA) test -- an indicator of prostate cancer risk, researchers reported here at the American Society of Clinical Oncology 2006 Annual Meeting (ASCO). However, it is possible to compensate for a high body mass index (BMI) when looking at the PSA reading. According to lead investigator Mark Garzotto, associate professor of surgery/urology, Oregon Health & Science University Cancer Institute, Portland, Oregon, prior studies have shown that overweight and obese men have a higher risk of developing prostate cancer. Obese men have been shown to have larger and less dense prostates. They also tend to have lower serum PSA levels because the protein is spread throughout a larger body mass. This means that although a man might show a normal or near normal PSA reading, he could, in fact, be at a significant risk of cancer. What is needed is a tool for adjusting a man's PSA, BMI, and prostate size in order to more accurately predict his risk of cancer, Dr. Garzotto said in a poster session on June 4th. His research team analyzed data on 647 men with PSA readings of ± 10 ng/mL. The men underwent digital rectal exams, and their prostate volumes were calculated using prostate ultrasounds. PSA density (PSAD) was calculated by dividing the PSA score by prostate volume. The study found that a man's PSA density decreased significantly as his BMI increased. However, a man's risk of cancer increased dramatically when his PSA density was compared with what a normal PSA density might be expected to be. For example, among men whose BMI was < 25 (ie, normal range) and whose prostate density was more than twice what would be expected in a matched control (ie, somebody of normal size and weight, and with normal PSA) his odds of developing cancer would be 1.71 (ie, a 71% greater risk of developing cancer; P <.0001). If the man's BMI was > 25 and his PSA density was double the normal level, the odds ratio of him developing cancer would increase to 2.09 -- more than a 2-fold risk of cancer. Being able to adjust for a man's BMI and PSA reading would be clinically important because the PSA level becomes more meaningful, and the man and his doctor would have a more accurate idea of what his risk of cancer might be. At the same time, the man could also be spared the trauma of a biopsy. As it stands right now, more than 2 million prostate biopsies are performed each year in the US and more than three quarters of them fail to show any signs of cancer or other abnormalities. "These data underscore the need to consider BMI as a potential effect modifier of traditional risk factors for prostate cancer," Dr. Garzotto said. The dramatic rise in the prevalence of obesity in the US makes this particularly relevant, since gaining a truer understanding of an obese man's PSA level could save him from needing to undergo a biopsy and spare the healthcare system the expense of these unnecessary procedures. [Presentation title: Effect of Obesity on PSA Density (PSAD): A New Clinical Predictor of Prostate Cancer. Poster 4617] Source: www.docguide.com, June 2006 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.