New study defuses controversy, shows why individual patient trends are critical
A man's rising PSA (prostate-specific antigen) level over several years – which had been seen as a possible warning sign of prostate cancer – has recently come under fire as a screening test because it sometimes prompts biopsies that turn out to be normal.
A new study, however, shows nearly 70 percent of men who had rising PSA levels and subsequent normal biopsies were eventually diagnosed with prostate cancer, according to research from Northwestern University Feinberg School of Medicine. The trend of a PSA level over several years is called PSA velocity.
"Our findings show an elevated and rising PSA level or velocity should lead a clinician to follow a patient more closely, even if he has a negative biopsy," said lead investigator William Catalona, M.D., director of the clinical prostate cancer program at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University. "One negative biopsy isn't the end of the road."
The findings were presented May 18 at the American Urological Association 2011 Annual Meeting. Catalona is a professor of urology at the Feinberg School and a urologist at Northwestern Memorial Hospital.
PSA is a substance whose elevated levels can indicate prostate cancer but can also be caused by prostate inflammation or enlargement or other conditions. Catalona, known as the father of the PSA screening, was the first to show in 1991 that a simple blood test measuring PSA levels could be used to detect prostate cancer.
For the study, Northwestern researchers looked in their database at the history of 97 patients with a rising PSA trend (or velocity) who had a subsequent negative biopsy. Researchers found 66 percent of patients were eventually diagnosed with prostate cancer, 20 percent had a benign prostate, 8 percent had protatitis and 6 percent had premalignant lesions.
"This underscores the importance of using a patient's individual PSA trend when deciding whether to pursue a prostate biopsy," said co-investigator Gregory Auffenberg, M.D., a resident in urology at the Feinberg School. "It's not enough to only look at an individual PSA value when historical data is also available."
