A Perspective About PSA Screening
by Justin Albani, MD
Recognized as Men’s Health Month, June is an appropriate time to talk about prostate cancer, the second most common malignancy affecting men in the United States and the second leading cause of cancer deaths. One in six men will develop prostate cancer and one in 36 will die of this disease, according to the American Cancer Society.
That’s why for over two decades, physicians have been using the serum prostate specific antigen (PSA) test to identify patients at risk.
PSA Screening Under Fire
In the first decade of PSA use, studies noted an initial increase in the detection rate of prostate cancers. Many more cancers are now detected long before patients become overtly symptomatic. The National Cancer Institute has reported a 40 percent decrease in the age-adjusted prostate cancer mortality rate in what is now known as the modern PSA era.
Despite these statistics, the test has come under sharp criticism for its lack of specificity for detecting prostate cancer. The debate continues today over the effectiveness of screening protocols for the general population.
Recently, the American College of Physicians discouraged PSA-based screening and the United States Preventive Services Task Force recommended against it, giving the test a grade D recommendation.
What is a clinician to do with this information?
Why Did The Task Force Recommend Against PSA?
It’s important to understand how the government panel arrived at its decision. Not one of the 16 doctors was a urologist, medical oncologist, radiation oncologist or even a physician-consultant with any experience treating prostate cancer patients on a regular basis.
The task force reviewed the two largest trials of PSA screening: the Prostate, Lung, Colorectal and Ovarian Cancer Screening (PCLO) from the U.S. and the European Randomized Study of Screening in Prostate Cancer (ERSPC) from Europe. The panel noted that the two studies had conflicting results and, unfortunately, did not take a closer look at the investigations later reported as extensions of these studies that noted a benefit to prostate cancer screening. These studies supported the belief that the true benefit of prostate screening is, as most oncologists and urologists recognize, realized in younger and healthier men.
A closer look at the PCLO and ERSPC
When the task force reviewed the PCLO trial, it noted that the trial showed no reduction in prostate cancer deaths among men who had regular PSA tests. But the panel failed to mention that this study was widely criticized because up to 52 percent of the non-screened control population was actually getting PSAs and digital rectal exams by their primary care physicians. This fact severely contaminated the study.
A re-analysis of the same study found that, if PSA screening was performed in men with low or no comorbidity, there was a 44 percent decrease in prostate cancer mortality and the number needed to treat (NNT) was calculated to be only 5 to save 1 life. Unfortunately, this important update to the previously well-publicized negative study garnered little to no media attention and was completely overlooked in the panel’s evaluation.
The ERSPC trial randomized 182,000 men in Europe to PSA screening every two to seven years or usual care. It reported a 20 percent reduction in prostate cancer mortality and a 41 percent decrease in metastatic disease in the screening arm in men followed for nine years.
The greatest criticism of this study noted the high number of men needed to be treated (48) to save 1 life. Interestingly, an additional trial (Göteborg) that was a subset of this patient population comprised of 20,000 men aged 50-64 screened every two years with a lower PSA cutoff (2.5-3.4) reported a 44 percent lower prostate cancer death rate in screened men, at a follow up of 14 years.
Not only did this study demonstrate that prostate cancer screening lowered the cancer death rate, perhaps more importantly, it reported a much lower number needed to treat (NNT) to save one life at only 12 patients. (This is comparable to breast cancer with a NNT of 10.)
Whether To Treat, Not Whether To Screen
The panel based its recommendations on its assumption that all screening leads to treatment, and thus overtreatment. The risk of overtreatment is real, but the panel made a gross generalization assuming that doctors do not consider a patient’s age, comorbidities, volume of disease or Gleason score.
Risk stratification has been in practice for years, allowing physicians to counsel patients on what treatment, or non-treatment, may be most appropriate. Active surveillance for prostate cancer is a common practice, and urologists now recognize that some prostate cancer is indolent and unlikely to present a problem in a patient’s lifetime.
The question should be whether to treat, not whether to screen.
Urologists’ Recommendation for PSA
The common consensus among treating urologists is to follow the National Comprehensive Cancer Network’s 2.2012 Guidelines and assign an abnormal to any PSA value > 2.5 ng/mL or a PSA velocity of > 0.35 ng/mL/yr.
You may cease screening if a patient has no family history of prostate cancer, has a normal digital rectal exam, is over 75 and has had PSAs < 3.
NCCN Guidelines 2.2012 for Early Detection of Prostate Cancer
- Obtain a baseline DRE/PSA at age 40 to assess risk
- If PSA < 1ng/mL, recheck at age 45, and if this remains <1ng/mL, recheck at 50, then annually
- If PSA > 1 ng/mL, recheck annually
- Consider referral to a urologist for prostate biopsy if PSA Velocity is >=0.35ng/mL / year or Total PSA is > 2.5 ng/mL or % free PSA is < 10%
- Consider cessation of prostate cancer screening if age > 75, PSA <3, DRE WNL, and no family history of prostate cancer
Justin Albani, MD
Dr. Albani earned his MD from Baylor College of Medicine. He completed his residency in urologic surgery at the Cleveland Clinic and a fellowship in robotic surgery and laparoscopy at the University of Pennsylvania. He has been practicing in the Northland since he joined Urology Specialists, PC in 2006. He currently serves on the editorial board of Missouri Medicine, the journal of the State Medical Association, as a urology board member.
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