Three Questions You Were Afraid to Ask About PSA Screening

[[{"type":"media","view_mode":"media_crop","fid":"47979","attributes":{"alt":"","class":"media-image media-image-right","height":"254","id":"media_crop_8356895626713","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"5705","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"margin: 8px; float: right;","title":"PSA molecule","typeof":"foaf:Image","width":"257"}}]]The most accurate adjective to describe the topic of PSA screening is the word controversial. PSA screening’s uncertain reputation stems from the need to ask a fundamental question: Does screening save lives? A recent editorial in JAMA Oncology¹ that adds significantly to our knowledge goes a long way to help us reframe the question--and the answer. Here’s how.

Does PSA screening save lives?

The answer, based on hard data from the European Randomized Trial of Screening for Prostate Cancer (ERSPC), now appears to be “yes.” The ERSPC demonstrated that PSA screening (even in a “relatively” older cohort) resulted in a 20-25% reduction in the risk of prostate cancer mortality at 13 years.^1,2 (Despite the good news, the authors are not ready to recommend population-wide screening.)

Where do we go with PSA screening now?

JAMA Oncology commentary author Andrew Vickers, PhD, says the debate has shifted away from the question of whether PSA screening does any good to whether PSA screening does more harm than good.¹ Framed this way, if more men are diagnosed with prostate cancer after PSA screening, might some be harmed by definitive treatment? Remember the old saying, “More elderly men die with rather than of prostate cancer.”

Some prostate cancers diagnosed by PSA screening do not need immediate therapy.¹ It has been demonstrated previously that mortality reductions with treatment were only achieved with intermediate- and high-risk disease (including Gleason Scores).^1,3 Some experts are even asking whether Gleason 6 adenocarcinomas, approximately 50% of screen-detected cancers, should be labeled as malignancies.^1,4 This is a very important question because these patients are often treated with radical prostatectomy or radiation. Such aggressive therapy is unwarranted, especially if the disease is not progressive.

The controversy over treatment for lower- and higher-risk disease has led to a conservative strategy described as “active surveillance.”¹ In this context, screening is curtailed in older men (>70 years of age), and is less frequent in others (up to 8-year screening intervals).¹ A more aggressive approach to initial treatment is also taken in those men with higher PSA scores.

How should PSA screening evolve?

We all have to change the question we ask from “Should we screen?” to “When is it appropriate to screen in the first place”?¹ If we screen and then intervene with low-risk cancers, we will be doing our patients a disservice. Right now there are 2 big mistakes being made: Unnecessary treatment for low-risk disease (60%) and over-screening in older men.¹The good news is that active surveillance of low-risk prostate cancers has increased 4-fold.¹ Lets proceed with Dr. Vickers reframe of screening and treatment practices with PSA.

References:

1.) Vickers AJ. Does prostate-specific antigen screening do more good than harm? Depends on how you do it. JAMA ONCOLOGY 2016; [e pub: 3-24, 2016] at jamaoncology.com. http://oncology.jamanetwork.com/article.aspx?articleid=250535

2.)  Schroder FH, Hugosson J, Roobol MJ, et al. ERSPC Investigators. Screening and prostate cancer mortality: results of the European Randomized Study of Screening for Prostate Cancer at 13 years of follow up. Lancet 2014; 384:2027-2035. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4427906/

3.) Wilt TJ, Brawer MK, Jones KM, et al. Prostate Cancer Intervention versus Observation Trial (PIVOT) Study Group. Radical Prostatectomy versus observation for localized prostate cancer. N. Engl. J. Med. 2012; 367:203-213. http://www.nejm.org/doi/full/10.1056/NEJMoa1113162

4.) Carter HB, Partin AW, Walsh PC, et al. Gleason score 6 adenocarcinoma: should it be labeled as cancer? J. Clin. Oncol. 2012; 30:4294-4296. http://jco.ascopubs.org/content/30/35/4294.long