Last year, the U.S. Preventive Services Task Force (USPSTF) finalized a controversial recommendation that general breast cancer screening should begin at age 50, not before then. The decision was controversial not just because of its implications for health insurance coverage but because society has been conditioned to believe that screening is a valuable part of preventive medicine. Unfortunately, that's not necessarily true.
The reason is due to false positives. If an initial screen produces a positive result, a doctor is likely to recommend a more invasive test. Not only does this cost the patient in terms of psychological distress and money, it also poses new medical risks. As it turns out, "invasive procedures" are called that for a reason.
This isn't just a theoretical concern. A new paper published in the journal Open Forum Infectious Diseases showed that 3% of men who undergo prostate biopsies end up being hospitalized within a month. Worse, half of those hospitalizations are due to an infection.
The authors used insurance records to obtain data on 515,045 prostate biopsies that occurred from 2005 to 2012. Then, they determined how many of these patients were admitted to the hospital within 30 days. Roughly 3% of those patients were hospitalized, half of whom for conditions such as sepsis (blood infection) or prostatitis (prostate inflammation). Forty-five patients died.
In addition to the pain and suffering caused by the biopsy, the median hospital stay was 3 days, and the average bill was about $15,000. Extrapolating their results, the authors estimate that infections acquired from prostate biopsies cost Americans $623 million every year.
There are two weaknesses to this study. First, the authors did not compare the hospitalization rate for men who received prostate biopsies with a control group (i.e., men who did not receive a prostate biopsy). Second, it is not possible to unambiguously conclude that all hospitalizations were due to the biopsy, though limiting the study to a 30-day window increases the likelihood that the biopsy was to blame.
The PSA (prostate-specific antigen) test, which measures a blood protein that potentially indicates the existence of prostate cancer, has a high false positive rate. In fact, according to the National Cancer Institute, only 25% of men with a positive PSA test who go on to receive a biopsy actually have prostate cancer.
That is just one of many reasons why the USPSTF recommends against the PSA screen*. And it provides a counterintuitive lesson applicable to all such health screens: The risk associated with screening for a disease sometimes outweighs the risk associated with the disease itself.
*Note: The USPSTF offers its recommendation in blatant defiance of Ben Stiller's medical advice.
Source: Richard Evans, Aram Loeb, Keith S. Kaye, Michael L. Cher, Emily T. Martin. "Infection-Related Hospital Admissions After Prostate Biopsy in United States Men." Open Forum Infect Dis 4(1): ofw265. Published: 13-Jan-2017. DOI: 10.1093/ofid/ofw265
SunglassesDan on April 22nd, 2017 at 14:48 UTC »
The article states that not all of those hospitalized for infection even had an infection involving the prostate, so for all we know this could be 0.01% getting hospitalized for prostatitis, 2.99% getting hospitalized for unrelated reasons. Given that the demographic of men receiving prostate biopsies is mostly age 60-80, a group that is not usually in perfect health to begin with, this statistic is basically useless.
ScepticalChymist on April 22nd, 2017 at 14:11 UTC »
US medical student here, and I wanted to chime in after reading some of the comments. First, let's talk about the qualities of a good screening test.
The disease being screened for should be an important public health problem: There's no sense in expending resources on developing tests and public health campaigns for a condition that has very little effect in the population. The disease in question should be treatable: Again, no sense in expending resources for screening if we can't treat the condition once it's identified. The disease should have a latent phase, and beginning treatment during this latent phase would be more advantageous than waiting until the active phase of disease: Cancer is the classic example because small tumors often go unnoticed, and waiting too long to initiate treatment increases the risk of local invasion and/or metastasis. The screening test should be acceptable to the test population: The ideal screening test is relatively inexpensive and noninvasive. For example, a rapid HIV test only requires a drop of blood. In contrast, a radical mastectomy for cancer screening purposes makes zero sense.So now, let's talk about prostate cancer and biopsy-related complications.
Is prostate cancer a significant public health concern? It's the 3rd leading cause of cancer deaths among US men. Is it treatable? There are medical and surgical treatment options. If there's a latent phase, does early treatment offer an advantage? This is where it's tricky. Prostate cancer is often slow growing and often has less of a tendency to metastasize. Some men are diagnosed after their cancer has been growing asymptomatically for years, and they are old enough at diagnosis that treatment offers no survival benefit, i.e. they will die with prostate cancer, not of it. As with all things cancer, there is huge variability among the types of prostate cancer though. Is prostate biopsy acceptable to the test population? As /u/illbeyourgentleman said, a 3% complication rate sounds pretty darn high to me when compared with other screening tests (even though the article says 3% are hospitalized within a month, not necessarily from screening complications, 1.5% is still high compared to screening tests for other diseases).It's also important to note, as /u/jgrizwald has, that the USPSTF recs differ from the US and EU urological societies. This is a very common phenomenon in medicine. Generally, medical societies tend to recommend more frequent/earlier screening than the Task Force.
Without delving into the literature on prostate cancer morbidity and mortality, I can't say whether this particular test is a good one or bad one. However, I think this is an important reminder that we need to weigh the risks and costs of screening versus the disease itself. At face value, it seems that knowing more about your health status must be better than knowing less. More information is good, right? Well, not necessarily. When a screening test results in a 1.5% infection rate and a cost of $623M in complications annually, I think we really need to reconsider the acceptability of this particular test to its test population. And as always, we should consider the cost of knowing versus the benefit of that knowledge.
jgrizwald on April 22nd, 2017 at 13:07 UTC »
This seems like the type of article that r/science should avoid due to oversimplification of a complex issue. The task force recently updated its recs and still don't fully coincide with US/EU urology societies recs.