Diagnosis + Stage - Screening for prostate cancer
The Case for PSA Screening Starting at Age 40
Thursday, 30 October 2008 19:00
When men should take their first PSA test to screen for prostate cancer is an issue that comes up constantly in discussions of mens' health.
The National Comprehensive Cancer Care Network (NCCN) recommends men to take their first PSA test at age 40. How soon and how often to take a follow-up PSA tests would then depend on this initial level.
This method is supported by Dr. Robert Nadler, of Northwestern University in a recent editorial in the journal Cancer. Dr Nadler reviews findings based on data collected in the Center for Disease Control's 2002 Behavioral Risk Factor Surveillance System. One surprising fact identified by a team at Duke University that analysed this data is that young, black, non-Hispanic men are more likely than young, white, non-Hispanic men to report having had a PSA test.
The CDC data show that 22.5% of men ages 40-49 had a PSA test the previous year, compared to 53.7% of men older than 50 years. More African-American men than Caucasian men were screened (33.6% vs. 21.5%).
One-fifth of young men said they'd had a PSA test within the previous year. Young, black, non-Hispanic men are more likely than young, white, non-Hispanic men to report having had a PSA test, although screening in this high-risk group remains suboptimal.
Most primary care physicians, Nadler says, are not aware of guidelines to screen men at age 40. A baseline PSA at age 40 serves as a starting point for determining risk, according to Nadler. He says the median PSA level for men in their 40’s is 0.7ng/ml and for men in their 50’s it is 0.9ng/ml. An age-specific median PSA between 0.7 or 0.9 and 2.5ng.ml results in a 14.6-fold and 7.6-fold increased risk of developing prostate cancer for men in their 40’s and 50’s, respectively.
The PSA's velocity or rate of rise is as crucial as any absolute number. Dr. Balenchine Carter reported that men with a PSA velocity of 0.35ng/ml/ per year or greater were 5 times more likely to die of prostate cancer more than 10 years later. Thus, a baseline PSA at age 40 serves as a starting point for determining PSA velocity and detecting prostate cancer in young men at risk.
Nadler suggests that to be effective, PSA needs to be measured yearly beginning at age 40, while the NCCN guidelines recommend if the initial PSA is 0.6ng/ml or less, it can next be rechecked at age 45.
Opponents of early PSA screening and speedy intervention as soon as prostate cancer is detected argue that treatment side effects can seriously hurt mens' quality of life. But according to Nadler, men with a PSA of 4.0ng/ml or higher who undergo radical prostatectomy have a 30% chance of positive surgical margins and thus worse outcomes. Decreasing the PSA threshold for biopsy and treatment to 2.0 or 2.5ng/ml would decrease this risk, Nadler writes. Nadler notes, further, that the death rate from prostate cancer in the US has decreased from 41,800 in 1997 to 27,050 in 2007.
The view that patches of unaggressive prostate cancer don't necessarily need to be treated as soon as found remains a counterargument. For men in this situation an increasingly popular option is active surveillance with expectant management. Nonethless, Nadler backs the NCCN guidelines and rationale for prostate cancer screening beginning at age 40.
Dr. Nadler's The case for prostate-specific antigen screening starting at age 40 is published in Cancer. 2008 Sep 15;113(6):1278-81. The report above draws on a commentary written for UroToday.com by that site's Contributing Editor Christopher P. Evans, MD, FACS.
Edited by J. Strax.
