There have been a couple of articles of note on prostate cancer and screening.
One was in this week’s New England Journal of Medicine (see DOI: 10.1056/NEJMsa1201141). The impetus for the study was to determine if urologists purchasing their own office-based, expensive intensity-modulated radiation therapy (IMRT) equipment were more likely to use this form of radiation therapy vs urologists who do not own the equipment. The researcher looked at Medicare claims from 2005 through 2010 in 2 samples: 1 was in private practice groups with 35 urologists self-referring for IMRT who started using this equipment during this time period versus 35 groups not owning this therapy; the other study was of a group of 11 non-self-referring urologists at National Comprehensive Cancer Network centers compared to 11 self-referring urology groups in private practice. The intention of the second study was to compare urologists who were likely to practice on the basis of clinical evidence and unlikely to derive personal financial benefits from the services, versus 11 matched self-referring private urology practices in close proximity to the centers. Findings:
–for the 35 private practice urology groups, the rate of IMRT use by self-referring urologists increased from 13.1 to 32.3%.
–for 35 non-self-referring urology groups during the same time period, the rate of a IMRT use increased only from 14.3 at 15.6%.
–For those urologists working at National Comprehensive Cancer Network centers, the use of IMRT remained stable at 8% but increased to 33% in the 11 matched nearby self-referring urology groups.
–The mean cost estimate of her IMRTwas $31,574, approximately twice that of a radical prostatectomy or brachytherap
Not surprising. Similar findings have been found for using advanced imaging techniques, clinical laboratory testing, and pathology services by self-referring physicians. There is also an increased use of surgery in physician-owners of specialty hospitals. Although the feds prohibit much self-referral, there are notable exceptions, including for radiation therapy.
The second article which came out several months ago was an update of the American Urologic Association guidelines for early detection of prostate cancer (see: http://www.auanet.org/education/guidelines/prostate-cancer-detection.cfm). There were several changes in these guidelines over prior ones. They still focus on PSA screening, given that there is little evidence supporting the clinical efficacy of DRE, PSA derivatives (eg free PSA, PSA velocity, etc), or novel biomarkers such as PCA3. They do acknowledge several harms from screening, including that more than 75% of people with a PSA greater than 3 have no cancer on biopsy, the cumulative risk of having at least one false positive test after 4 rounds of annual testing was around 13%, and over-diagnosis of prostate cancer was on the order of 66% (approximately 1/3 of the screen-detected cases). Their general recommendations are as follows:
–Not screen men under age 40
–Not do routine screening in men between 40 and 54 years of age at average risk. They recommend individualized decisions on prostate cancer screening in these younger men at higher risk (e.g. positive family history, or African-American men)
–For men aged 55-69, “the panel recognizes that the decision to undergo PSA screening involves weighing the benefits of preventing prostate cancer mortality in one man for every one thousand men screened over a decade against the known potential harms associated with screening and treatment. For this reason, the panel strongly recommends shared decision-making for men aged 55-69 years that are considering PSA screening, and proceeding based on a man’s values and preferences.”
–The screening interval of 2 years or more may be preferred over annual screening to reduce the harms of screening, preserving the majority of benefits and reducing over-diagnosis and false positives.
–Not screening men over 70 or men with a less than a 10-15 year life expectancy.
so, these new guidelines definitely reflect a softening of their position on screening. still clearly supports screening with the caveat that there should be shared decision-making. pretty hard to do that when we, as trained medical providers able to decipher the intricacies of the different studies and their methodologies, are pretty clueless as to what to do. I will also follow this post with a prior discussion–see below.
From March 2013:
in one of my precepting sessions, the question came up about the utility of finasteride as well as the predictive accuracy of PSA screening. finasteride does do well in decreasing prostate volume, though it takes months to work. but i wanted to circulate 2 important articles (both from the prostate cancer prevention trial), which i think sheds light on these issues.
1. prostate cancer prevention trial — 7 year study of 19K men >55yo, with PSA <3 and nl DRE, randomized to finasteride 5mg/d vs placebo. rationale of study is high prevalence of prostate cancer in men (17% lifetime risk). found that prostate cancer was reduced by the prophylactic administration of finasteride by 25% (24% in the placebo group, and 18% with finasteride). BUT, higher incidence of high-grade prostate cancer (Gleason scores 7-10) in the finasteride group (6.4%) vs the placebo group (5.1%). also sexual side-effects of finasteride. but, bottom line, concern that there may be more high-grade, potentially lethal prostate cancers with finasteride.
2. prostate cancer in those with low PSAs — this looked at the placebo group at the end of the above 7 year study, where they did a prostate bx in 3K men in the placebo group who never had PSA>4 or abnl DRE. rather striking findings as follows:
-15.2% had prostate cancer, breakdown as follows:
-psa <0.5, 6.6% with prostate cancer (!!!)
-psa 0.6-1, 10%
-psa 1.1-2, 17%
-psa 2.1-3, 24%
-psa 3.1-4, 27%
-of those who had prostate cancer, 15% of them had high grade cancers (Gleason 7-10), breakdown as follows:
-psa <0.5, 12.5% of those in that psa group with cancer had high grade lesions
-psa 3.1-4, 25% with high grade lesions.
bottom line, increasing psa is associated with more cancers and high-grade cancers, BUT psa is a pretty miserable test, does very poorly in terms of its sensitivity (and, if you lower the sensitivity to a cutpoint of 3 or 2, the number of biopsies done in the population increases dramatically and you still seem to miss a fair number of even high grade cancers).
hope this is helpful.