Prostate cancer is now the most common non-skin cancer diagnosed in men in the United States. According to the American Cancer Society, approximately one in six men will be diagnosed with the disease in their lifetime, with more than 220,000 new cases identified annually. Although it is the second leading cause of cancer-related death in men (behind lung cancer), if detected early the relative five-year survival rate for local and regional stage prostate cancer is nearly 100 percent.
For many years, the common test used to screen for prostate cancer was a digital rectal exam (DRE), which for many men is as uncomfortable to receive as prostate cancer is to talk about. In the early 1980s, a blood test called prostate specific antigen (PSA) was developed. PSA measures a protein released from prostate tissue (cancerous and non-cancerous), and came into use as a means of monitoring response to prostate cancer treatment and detecting recurrence. Over time, interest grew to use this blood test to screen for disease (prostate cancer) rather than just monitor known disease.
In 1994, the FDA approved the use of the PSA test in conjunction with a DRE to test asymptomatic men for prostate cancer, which helped to significantly increase the number of early diagnoses. There was optimism that its widespread use would save lives. Taken from a certain perspective, it has: the five-year relative survival in men with prostate cancer is now about 99% – what could possibly be wrong with that?
Consider the following statistics:
- At least 2/3 of men over 70 have some prostate cancer detected upon autopsy, even if not previously diagnosed
- About one in six men will be diagnosed with prostate cancer in their lifetime
- Only about 2% of all men die of prostate cancer
- Less than 1% of men aged 55 to 69 will die of prostate cancer within 10 years
What this tells us is that prostate cancer is common, and more importantly, very few men die from it. You might wonder, “Maybe it’s because they had PSA testing done.” Well, the reality is that most men, diagnosed or not, won’t die from prostate cancer. Therefore, while PSA has led to a significant increase in the number of diagnoses, we’ve seen a much, much smaller decrease in the number of deaths.
In late 2009 and early 2010, two large, international trials – Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) and the European Randomized Study for Screening of Prostate Cancer (ERSPC) – were published, leading to a shift in how PSA was viewed for prostate cancer screening. PLCO reported that men who underwent annual prostate cancer screenings with PSA testing and DRE had a 12 percent higher incidence of prostate cancer, but the same rate of death from the disease as the control group.
While the ERSPC showed a 20 percent (one in five) reduction in the number of deaths from prostate cancer in men 55 to 69 years old, the researchers determined that because they screened men with PSA on average every four years rather than the annual PSA test that many in the U.S. are used to (and which was the focus in PLCO the findings), the results were not sufficient to justify population-based screening. These studies also showed there were harms associated with follow ups of abnormal screening tests and with treatments.
Around this time, the United States Preventive Services Task Force (USPSTF) also recommended against PSA to screen for prostate cancer due to the lack of lives actually saved. USPSTF found that in men aged 55-69, we would expect five deaths per 1,000 from prostate cancer without PSA screening, while men in the same age range who did receive a PSA screening would experience four to five deaths. Additionally, approximately 10 percent of those in the study showed a false positive, but no evidence of the disease was found present after invasive testing like a biopsy – leading to high levels of anxiety and unnecessary tests. Furthermore, another 10 percent who received a true positive PSA result, meaning they had the disease, were shown to be at risk for serious and sometimes fatal complications upon further treatment.
While the PSA blood test itself does not directly cause the above problems, it can certainly open the door to these issues. In its analysis, the USPSTF concluded that the small benefit – one life saved per 1,000 screened – does not outweigh the potential risk or harm the PSA test may cause.
These findings led the American Urologic Association (AUA) to be more conservative in its recommendations for these screenings, stating that men under 40 should not have the PSA screening and men ages 55-69 should consider the test, but not more than every two years.
So how do I advise patients who want to know whether they should have their PSA checked? In my practice, I often reference the 2013 AUA guidelines and generally recommend the following:
- If you’re under 40 and asymptomatic, there’s no data to support PSA screening, and you’re at low risk for prostate cancer
- If you’re 40-55 and asymptomatic but at high risk for prostate cancer – based largely on race or a strong family history, particularly at an early age – talk to your doctor. You may stand to benefit more and worry less about the associated risks. (And if you’re 40-55 and at average risk, the AUA guidelines state that routine screening is not recommended.)
- If you’re 55-69 and asymptomatic, you should review the pros and cons of PSA testing. It can significantly reduce your risk of dying from prostate cancer, but marginally impacts overall survival, and is more likely to lead to unintended harm than a life-saving intervention. Talk to your doctor, as there is no one right decision
- If you’re 70+ and asymptomatic with no personal history of prostate cancer, there’s no data to support PSA screening
If you think you are experiencing new or changing symptoms of prostate cancer (such as a need to urinate frequently, especially at night; painful or burning urination; blood in urine or semen; and/or frequent pain or stiffness in the lower back, hips, or upper thighs) speak with your physician to determine what is most appropriate for you.