"Some studies have shown that obese men are more likely to have deadly prostate cancer, yet diagnostic tools like PSA are less likely to accurately predict the presence of cancer in this population," said Mark Garzotto, M.D., an Oregon Health & Science University Cancer Institute researcher who will present the study at the 2006 annual meeting of the American Society of Clinical Oncology on Sunday, June 4.
PSA is a protein made only by prostate cells. Certain prostate conditions, including prostate cancer, are associated with high levels of PSA in the blood. However, obesity or high body mass index (BMI) has been tied to lower PSA levels. BMI measures weight in relation to height.
Compounding this diagnostic difficulty is that increasing BMI leads to increasing prostate size, but, again, lower PSA. Larger prostates produce more PSA in men with normal BMI's, not less.
"This is a perfect storm in the diagnostic world," said Garzotto, who has studied and developed more accurate methods of diagnosing prostate cancer. Today, just one in four men who receive prostate biopsies after positive screening tests for cancer actually are diagnosed with the disease. "We needed a better understanding of how BMI affects prostate cancer diagnosis and what can be done about it," he said.
For this study, Garzotto and his colleagues conducted a retrospective study of clinical data for 647 men with a PSA of 10 or greater and who had an ultrasound-guided prost
Contact: Rachel MacKnight
Oregon Health & Science University