Diagnosis by Reporter?

As I have noted I am not licensed to practice medicine. Thus when I write I do so at best as an informed professional and as one who has written extensively and professionally on the topic for well over a decade. There are times when I shake up my urology colleagues but having experience in both statistics and medicine I have been able to assess many reports. Take the PSA issue.

Some ten years ago I wrote a piece critiquing the then recent American and European studies denigrating any use of PSA tests. In my opinion and in my experience they were fatally flawed. I wrote so in this Blog as well.

Simply stated, if one were to perform annual PSA tests which included PSA and %Free PSA and then calculated the Velocity of the PSA increase one can do pretty well in anticipating PCa. The following are two classifiers that we have developed.

The 4K test add a few other variables. Now %Free is a powerful marker because benign cells generate free PSA whereas malignant do not. Also the prostate continues to grwo as one ages and as it grows it generates more PSA. However is %Free remains high, 35% or so, it is a good chance that things are fine. Also velocity demonstrates rate of growth, benign is slow and steady and malignant takes off.

Now some NY Times writer,  it seems they are the ones who hold the golden truth about everything, writes:

In the most definitive study done to date to assess the value of PSA screening, the European Randomized Study of Screening for Prostate Cancer concluded that 781 men aged 55 to 69 when they enrolled would have to be screened to prevent one man from dying of prostate cancer after 13 years. In this study, approximately one man in six who were screened was falsely identified as possibly having prostate cancer, and two-thirds of positive PSA results in the first round of screening were false-positives.

However these studies did not reflect actual accepted procedures. The European study was so flawed since it tested men only infrequently, years apart. PSA testing demands annual tests with detailed data analysis. The author continues:

Among older men, screening can be beneficial to those 70 or over who are very healthy and expected to live another 10 years or longer. ... urologist at Johns Hopkins Hospital, noted in an editorial in JAMA that “older age is associated with more aggressive prostate cancer; thus, a very healthy older man with the prospects of extended life might benefit from PSA testing. “Nevertheless,” he added, “routine screening of average risk men 70 years and older should be rare, because they are more likely than younger men to experience the harms of screening, diagnosis and treatment.”

Death from PCa is excruciating. It infiltrates the bone and collapses the spine and ends often with DIC, a complete collapse of the blood system. Thus one must ask what is "routine" and who gets to select? Clearly with a Medicare for All scheme the Government would banish screening totally!

Finally the author notes:

One is the 4Kscore test that combines the levels of four prostate-specific antigens with clinical information to estimate a man’s risk of having an aggressive cancer. The other, called the PHI, for Prostate Health Index, combines three different PSA measurements to better predict the presence of cancer. Also under study is the use of an advanced form of M.R.I. that can detect the presence of cancer with a higher risk of becoming lethal while overlooking low-risk disease.

 4K and the others are well worth the effort. 4K relies heavily on PSA and does seem to be useful. MRI, especially multi parameter MRI, mpMRI may also be of use but I have seen many false negatives. For example in a patient with several prior biopsies the scar tissue may appear as a concern. Diffusion weighted MRIs give some sense of vascularity. Work is continuing on this topic and frankly it is one of my current efforts. Close but no cigar, yet!