The PSA screening debate was growing stale. Here are a few landmarks over nearly 50 years:
- Early 1970s – Richard Ablin, MD and others identify prostate specific antigen (PSA) as a biomarker for disease or disturbance in the prostate.
- 1987 – Thomas Stamey, MD notes that PSA is useful to monitor PCa patients for changes
- Early 1990s – The PSA blood test is promoted as a screening tool for PCa
- After 1993, the prostate cancer death rate begins declining about 17% per year
- 2008 – U.S. Preventive Services Task Force (USPSTF) recommends against screening for men ages 75+, says evidence is inconclusive whether benefits outweigh harms of overtreatment for younger men
- 2012 – USPSTF recommends against PSA screening for all men. Professional societies and patient advocacy groups disagree but screening rates start to decline.
- 2014 – Data from the National Cancer Institute shows a 51% decrease in PCa deaths since 1993, attributable to PSA screening but possibly also to other factors.
- 2016 – Studies suggest that while rates of PCa diagnosis are lower, there are higher rates of diagnosing aggressive PCa
- 2018 – USPSTF recommends that doctors and patients make case-by-case decisions after informed conversations about the merits vs. risks of PSA screening.
Today’s status quo
Does PSA screening reduce PCa mortality, or doesn’t it? We know that PSA is not specific for cancer, since many prostate conditions can cause a rise in PSA blood levels. We also know that an elevated PSA can lead to a conventional TRUS-guided biopsy, and that such biopsies can either miss PCa (30% rate of false negatives), or overdetect insignificant PCa, or underdetect significant PCa. Finally, we know that the detection of insignificant PCa can lead to whole-gland overtreatment with risks of short- and long-term urinary and sexual side effects.
Thus, the 2018 USPSTF counsel that PSA testing is an individual decision seems to be the prevailing practice in the U.S., with occasional “screening events” still offered by patient programs. But the core question remains: Does PSA testing save lives?
2018 published study based on 400,000 patient records
Paul Alpert, a urologist with UC/San Francisco School of Medicine and the Kaiser Permanente Medical Center published a 2018 paper on the lifesaving benefits of PSA screening. The cohort included the records of “400,887 men under age 80, with no history of prostate cancer, who had PSA testing at Kaiser Permanente Northern California.[i]
The study design afforded maximum data harvesting and interpretation:
The 5-year study period 1998-2002 was selected because there were prior PSA data going back to 1992, allowing for 6-11 years of prior data to examine screening intervals. This study period also provided 12-16 years of follow-up on patients diagnosed with prostate cancer, an amount of time deemed reasonable to calculate mortality rates.[ii]
The men were sorted into 6 groups according to screening interval (how far apart they received regular PSA tests) and 7 groups according to age. The objective of the analysis was to determine whether PSA screening reduced prostate cancer mortality, and if there is an optimum interval for greatest lifesaving benefit. The size of the database helps offset the lack of randomization, but the database itself had built-in limitations. For instance, if the first record of a man having a PSA test is October, 1999, the file might not indicate if it was simply a screening PSA (no reason to suspect PCa) or a “PSA for cause” (a symptom or risk factor that triggers a PSA blood test).
What the study found
After adjusting for various artifacts, based on the data the author concluded that
…yearly PSA screening is highly beneficial, reducing prostate cancer deaths by 64% for men aged 55-74 years, and reducing all-cause mortality in this group by 24%. Yearly screening is the interval of choice. No benefit was found for men under age 55. When combined with active surveillance to prevent overtreatment, these data lend support for yearly population-based PSA screening for prostate cancer for men aged 55-74 who are in good health.[iii]
Alternatives to overtreatment
The USPSTF recommendations barely avoided throwing the baby out with the bath. Why give up PSA screening, which Alpert’s study shows to be lifesaving, when multiparametric MRI (mpMRI) resolves biopsy and treatment dilemmas? Imaging using mpMRI a) eliminates unnecessary biopsies, b) guides real-time targeted biopsies that are efficient and diagnostically productive, and c) guides real-time focal therapies that control cancer while avoiding side effects. Until science produces a highly accurate and specific biomarker screening tool, the PSA blood test coupled with mpMRI offers the best means to save men’s lives from prostate cancer deaths.
NOTE: This content is solely for purposes of information and
does not substitute for diagnostic or medical advice. Talk to your doctor if
you are experiencing pelvic pain, or have any other health concerns or
questions of a personal medical nature.
[i] Alpert, P. New evidenced for the benefit of prostate-specific antigen screening: data from 400,887 Kaiser Permanente patients. Urology. 2018 Aug;118:119-26. https://www.sciencedirect.com/science/article/pii/S0090429518303765