Overdiagnosis – the word makes no sense

April 13, 2017

In the recent hubbub about the use of PSA to screen for prostate cancer, the word overdiagnosis has appeared several times. In an online dictionary, it is defined as “the diagnosis of a disease more often than it is actually present.”

But the diagnosis of prostate cancer is pretty straightforward, with a biopsy determining whether cancerous cells are present. The diagnosis can be either correct or incorrect. But, there can be overtreatment, when low-risk prostate cancer is treated aggressively. So somehow, overtreatment has spilled over into diagnosis to produce the word overdiagnosis. That is, if a person has a biopsy confirmed prostate cancer, which is low risk and receives aggressive treatment – he has been over treated, not over diagnosed.

 

Advertisements

EPCA-2 Update number 6

March 19, 2015

jail

For no particular reason, I searched for Dr. Getzenberg in Google. To recall about previous entries on this blog, search for EPCA-2 on this blog. (there is a search form on the top right of this blog). I found two rather different entries in Google.

One deals with the seventh retraction for articles written by Dr. Getzenberg

Another talks about awards distinction and how he is a senior leader in oncology and urology.


The problem with surveys

December 7, 2013

committee

I recently took a survey and as for many surveys, there were a few questions for which none of the answer choices seemed to fit. In the case of this survey, I knew the author of the survey and emailed him my concern. His answer illuminated things.

The survey was about prostate cancer treatment by proton beam therapy (a form of radiation) and the question was: “How would you describe the quality of your life TODAY: better than, same as, or worse than before proton treatment?” The author was thinking that proton beam therapy side effects are minimal as compared to – for some – the life altering side effects of surgery. Moreover, the author had non prostate related health counseling that improved his life so for him, the choice was clear – his quality of life was better.

For most of us, prostate cancer has no symptoms – the only way we know we have it is an elevated PSA followed by a biopsy. Also for most of us, proton beam therapy side effects are minimal but there are still side effects; hence the only logical way to answer the question is that quality of life is worse than before proton treatment. Of course, the quality of life for some might be better – say if you hit the lottery, but this is unrelated to treatment.

One way of preventing these issues is to test the survey with a subset of the intended recipients. This should help but perhaps another thing to do is to add a response to every question that is something like: “this question cannot be answered with the above choices.”


Beware of Expert Panels

October 9, 2012

 

Ioannidis has written an interesting article (1) about biomarker failures, but I don’t agree with his first example of a failure. He says that PSA is a failure and “largely useless— or even harmful—and therefore needs to be abandoned.” He offers as evidence the recent USPSTF recommendation, which recommends against PSA screening altogether (2). 

But there are several reasons to question abandoning PSA. For one, the USPSTF data analysis has been challenged (3). Secondly, an update (4) from the ERSPC Trial showed that PSA screening does significantly reduce death from prostate cancer whereby a man who undergoes PSA testing will have his risk of dying from prostate cancer reduced by 29%. And thirdly, one can question whether cost played a role in the USPSTF conclusion. The USPSTF is empowered by the Affordable Care Act. Ezekiel Emmanuel, President Obama’s special health care advisor suggested  (5) that “the complete lives system produces a priority curve on which individuals aged between roughly 15 and 40 years get the most substantial chance [of healthcare resources], whereas the youngest and oldest people get chances that are attenuated.” PSA screening has been recommended to start at age 50.

There would be considerable cost savings for: 

  • the population of men over 50 in the US (or between 50 and 75) that would no longer receive a PSA test
  • the number of men that would have had an elevated PSA that would not receive a biopsy
  • the number men that would have been diagnosed with early prostate cancer via a PSA test / biopsy (~ 200,000 per year) that would not receive treatment (surgery or radiation) 

So in spite of the fact that PSA has many false positives (and some false negatives) and that there is overtreatment of prostate cancer, just because an expert panel concluded to abandon PSA, this does not mean it is the right conclusion. 

References 

  1. Ioannidis JP, Biomarker Failures Clin Chem 59 in press.
  2. Moyer VA, on behalf of the U.S. Preventive Services Task Force. Screening for prostate cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 2012;157:120–34.
  3. Schröder, FH, Stratifying Risk — The U.S. Preventive Services Task Force and Prostate-Cancer Screening N Engl J Med 2011; 365:1953-1955.
  4. Schröder, FH, Hugosson, J, Roobol, MJ, et. al. Prostate-Cancer Mortality at 11 Years of Follow-up N Engl J Med 2012;366:981-90.
  5. Persad G, Wertheimer A, Emanuel EJ, Principles for allocation of scarce medical interventions. Lancet 2009; 373: 423–31.

Ioannidis is Wrong

September 29, 2012

 

For some time, I have been a follower of John P.A. Ioannidis, but I don’t agree with his recent analysis of PSA as a screening tool. He says that PSA is a failure and “largely useless— or even harmful—and therefore needs to be abandoned” He offers as evidence the recent USPSTF recommendation, which recommends against PSA screening altogether. Of course, PSA does have false positive problems and overtreatment is an issue. But …

An update from the ERSPC Trial states that “The European Randomized Study of Screening for Prostate Cancer has published its 11-year follow-up results (New England Journal of Medicine, March 15 2012). Once again, they demonstrate that screening does significantly reduce death from prostate cancer. The latest study confirms that a man who undergoes PSA testing will have his risk of dying from prostate cancer reduced by 29%.”

And one can listen to an oncologist, who had metastatic prostate cancer and recovered, and now treats prostate cancer patients.

The USPSTF is empowered by the Affordable Care Act. It’s clear that healthcare spending by the government must be reduced. There would be considerable cost savings for: 

  • the population of men over 50 in the US (or between 50 and 75) that would no longer receive a PSA test
  • the number of men that would have had an elevated PSA that would not receive a biopsy
  • the number men that would have been diagnosed with early prostate cancer via a PSA test / biopsy (~ 200,000 per year) that would not receive treatment (surgery or radiation)

Isn’t it likely that cost had a role in the USPSTF decision? But this is not covered in the Ioannidis article.


PSA and Obamacare

May 29, 2012

Having a personal experience with prostate cancer, I saw a blog entry which I can’t improve upon, so here it is.


New Markers – too good to be true?

April 13, 2012

One thing that in-vitro diagnostics people know is that new markers never seem to turn out as good as the initial publications. This has now been studied and is available, here. Included in this analysis are CRP, prostate markers, and others. Ioannidis and Panagiotou compared the initial publication results with meta-analysis and larger study results and confirmed that the effects claimed in the initial publications were often found not to be as large in the larger study or meta-analysis.

If the initial study were unbiased, one would expect the larger studies would show greater effects half of the time and less effects the other half.