From ATLANTA Medicine, 2014, Vol. 85, No. 2
To screen or not to screen, to treat or not to treat. The gold standard for prostate cancer screening is for men to undergo both a digital rectal exam (DRE) and a Prostate Specific Antigen (PSA) blood test (Figure 1).
The debate on prostate cancer continues to revolve around the efficacy and usefulness of PSA as a valid screening tool as well as the decision-making ability of clinicians to appropriately decide which patients should undergo treatment and which should not. In all honesty, it is a reasonable debate given the information and the current tools that we have at our disposal.
There is no doubt that the future of medicine and cancer lies within the “double helix.” The ability to unlock the DNA code will one day give us some insight in regards to predicting who will die of cancer and who may succumb to more natural causes. This insight is lacking in our PSA/prostate cancer decision tree and has led many patients to be overtreated, but it has also led many patients to be poorly screened, leading to delayed and late presentation of disease.
Let’s try and break down the debate with a few examples of patients you see every day in your practice.
A 75-year-old healthy male walks into your office for a routine physical exam. You will obtain a lipid profile, check his blood sugar, check his urine and stool for blood, check his LFT’s and do a thorough physical exam. But, should you check his PSA this year?
Every year prior, his PSAs have been within normal limits. What are the chances at age 75, having not been diagnosed with prostate cancer thus far, that he will die from this disease? If we think his overall chance of death from prostate cancer is very low, why screen for it? In other words, why search for something that may likely be present (given the fact that as you get older your risk of prostate cancer rises) but may likely be clinically insignificant and may not require treatment. This would be a prime example of a patient that, if screened and diagnosed, could be overtreated (treated for a disease he will likely not die from).
A 55-year-old male presents to your clinic for his yearly physical. He recently completed a colonoscopy, exercises 3 times per week, does not smoke or drink and takes only a medication to help lower his cholesterol. Do you obtain a PSA as part of his routine laboratory evaluation? Based on new government guidelines, PSA is a poor screening test and does not impact the overall death rate from prostate cancer. But he is healthy, has at least a 25- to 30-year life expectancy and detecting prostate cancer (if in fact he is harboring it) at an early stage can potentially be curable. If you choose to adopt the government guidelines, you risk ignoring and missing the most common cancer seen in men and the leading cause of cancer-related death in men. This is a prime example of a man who could be under-screened and potentially die from a disease given his long life expectancy.
It has been established that those patients with risk factors for development and diagnosis of prostate cancer need to be aggressively screened and potentially treated. These men include those with a family history of prostate cancer (first-degree relative such as a father or brother) as well as those men who are African American. The American Urological Association (AUA) Guidelines (Figure 2) recommend that for men with risk factors, there should be an establishment of a baseline PSA value in their 40s, with annual screening beginning in their 50s. It advocates screening for all men to start in their 50s, regardless of risk factors.
The AUA has not accepted the recent statement put out by the United States Preventative Services Task Force (USPSTF) in regards to prostate cancer screening but has commented on the fact that interpretation of the PSA test and evaluation by the correct individuals may contribute to identifying those patients who would benefit most from annual PSA testing and screening.
The debate comes down to a simple fact: the error with PSA does not lie within the test itself, but instead in how we choose to use the test and how the test is interpreted. There is no doubt that PSA as a screening tool is far from perfect. We know that PSA may be elevated naturally with BPH, infection, inflammation, recent catheterization or urinary retention. At very high levels, PSA may correlate with aggressive prostate cancer, but on its own it is not diagnostic.
PSA can be interpreted based on absolute value as well as trend and change. PSA velocity as well as PSA doubling time have been shown to play a role in predicting diagnosis of prostate cancer as well as even death from prostate cancer. Other PSA tests, including Free PSA, PSA Density and Pro PSA, may help to differentiate benign elevations in PSA as well as differentiate slow-growing from more aggressive, rapidly growing tumors. Molecular marker testing provided by certain companies, recently highlighted in The New York Times, has brought some insight into predicting who may be harboring more aggressive diseases, therefore allowing physicians to avoid overtreatment.
Figure 2: PSA Screening Recommendations*
HIGH RISK PATIENT** LOW RISK PATIENT***
BASELINE PSA AT AGE 40 AND 45 NO BASELINE PSA NECESSARY
PSA ANNUALLY AFTER AGE 50 PSA ANNUALLY STARTING AGE 50
**High Risk Patients: Family history (first-degree relative diagnosed with prostate cancer) or African American
***Low Risk Patients: No family history or Caucasian, Asian, Middle Eastern
*Risk of prostate cancer in regards to age, absolute value of PSA as well as rate of change of PSA should be made by your urologist. Determination of need for a prostate biopsy for diagnosis of prostate cancer should be made by your urologist.
We as physicians have all come to realize that medicine in all of its perfection continues, in many regards, to still be an imperfect science. Decisions that we make on how to manage and treat our patients are based on the current tools that we have at our disposal, in this case PSA, but appropriate use of those tools is what defines us as physicians. A better screening and diagnostic test for management of prostate cancer is inevitable, as are the case for so many things in medicine, as technology advances us to see things on a molecular level. However, abandoning a test altogether continues to put a population of men at risk of dying from disease that is potentially very curable. Once again, it is not the test that is flawed as much as it is the interpretation and use of it.
Rajesh Laungani, M.D. is a urologist and serves as the Director of Minimally Invasive and Robotic Urology at Piedmont Hospital in Atlanta. He received his medical degree from the State University of New York Downstate College of Medicine and completed his surgical internship and urology residency at Henry Ford Hospital in Detroit, Mich., where he earned a fellowship in Minimally Invasive and Robotic Surgery from the Vattikuti Urology Institute. He earned his undergraduate degree from Brooklyn College. He maintains a strong interest in prostate cancer research and education and has ongoing collaborations with Georgia Tech, Clark Atlanta University and Emory University.