By Mark Scholz, MD of Prostate Oncology Specialists
The Challenge of Screening for Prostate Cancer
Most elderly men already have prostate cancer—they just don’t know it. And they might be better off remaining ignorant. Newly-diagnosed men are thrown into an eight-billion-per-year medical world that extols radical treatment. Over-treatment is so out-of-control a New England Journal of Medicine study estimates that forty-eight men are getting unnecessary surgery or radiation for each individual who truly benefits.
Random Biopsy, Not PSA is the Real Problem
When PSA is elevated, primary care physicians usually refer to a urologist for an immediate 12-core random prostate biopsy. A million men are biopsied annually in the United States. Few people realize that biopsy will be positive 20% of the time, even when PSA is normal. The problem is that a diagnosis of cancer, even Low-Risk cancer, almost invariably leads to surgery or radiation.
Biopsies Are Not Benign
Over-diagnosing Low-Risk prostate cancer, and the attendant risk of over-treatment, is not the only problem caused by random biopsy. Consider the emotional devastation caused by a cancer diagnosis. Men are literally frightened to death by the discovery of prostate cancer: The first week after diagnosis, the risk of suicide and heart attacks jumps dramatically. Three percent of men suffer biopsy-induced infections resulting in hospitalization. Fatal infections occur in approximately one-thousand men, a mortality risk of 0.1%.
Stop PSA Screening?
Due to all these mounting negatives, the U.S. Preventative Services Task Force now recommends that routine PSA testing cease altogether. The Task Force’s conclusion was that unnecessary treatment to over a hundred thousand men annually is too big a price to pay even though PSA screening saves lives. What the Task Force fails to realize is that the problem of overtreatment isn’t caused by the PSA blood test itself, it’s what physicians are doing with the information PSA provides by referring every patient with PSA elevation for immediate random biopsy.
Getting Back to PSA: It’s all about Prostate Size
People have to realize that most PSA originates from the prostate gland, not from cancer. Therefore, when the cancer is relatively small, PSA simply reflects the size of the prostate gland. Studies show that when cancer is absent, PSA averages one-tenth of the prostate volume. For example, the average PSA for a 30cc prostate is 3; five for a 50cc prostate and 10 for a 100cc prostate. Volume is measured with ultrasound or MRI.
PSA can only be termed abnormal, therefore, when its 50% higher than expected. For example, an abnormal PSA for a 30cc prostate is 4.5, a 50cc prostate, 7.5 and a 100cc prostate, 15. Of course additional extraneous factors such as low-grade infections, lab variations and recent sexual activity can also cause PSA to vary. Repeat testing helps average out these variations so the “real” PSA can be determined.
Primary Care Doctors Are the Source for Balanced Counsel
Only the primary care physicians can stop the mindless rush to random biopsy. Instead of referring for random biopsy they can send their patients with elevated PSA for prostate imaging with multiparametric MRI or Color Doppler Ultrasound. Imaging can put the PSA elevation into context by determining the prostate size. Also, in the hands of an experienced radiologist using state-of-the-art 3-Tesla MRI, high-grade cancer can be ruled out with 95 to 98% accuracy.
If imaging detects a high-grade lesion, primary physicians can then counsel their patients about whether a targeted biopsy directed at the abnormal lesion should be performed. Alternatively they can recommend simple monitoring with a repeat imaging study six to twelve months down the road to determine if the lesion is growing. Lastly, if a targeted biopsy shows cancer, rather than being guided by a urologist, who is a surgeon, patients can obtain counsel from their primary physician, a non-surgeon who can provide unbiased assistance in selecting the best treatment.
Estimating Cancer Risk
If men are concerned about the risk forgoing an immediate random biopsy they can estimate the percentage likelihood of harboring low-grade or high-grade disease with an online calculator by googling, “risk of biopsy-detectable prostate cancer.”
Prior to PSA screening men should know about imaging. They also should know how random biopsy often uncovers Low-Risk cancer, a condition that almost always leading to unnecessary treatment. PSA screening, therefore, is potentially harmful unless men and their physicians are first informed about the risks associated with doing a random biopsy.