Thursday, May 10, 2018

They are at it Again!

The USPSTF is issuing a new and updated recommendation. The "new" recommendation is:

The USPSTF concludes with moderate certainty that the net benefit of PSA-based screening for prostate cancer in men aged 55 to 69 years is small for some men. How each man weighs specific benefits and harms will determine whether the overall net benefit is small. The USPSTF concludes with moderate certainty that the potential benefits of PSA-based screening for prostate cancer in men 70 years and older do not outweigh the expected harms.

Now read this carefully. "for some men" really means that we still have no idea how to identify the deadly form of PCa. So if a man has "harms" he should consider "death" as an alternative?

They note the harms of the test:

The harms of screening for prostate cancer include harms from the PSA screening test and subsequent harms from diagnosis and treatment. Potential harms of screening include frequent false-positive results and psychological harms. One major trial in men screened every 2 to 4 years concluded that, over 10 years, more than 15% of men experienced at least 1 false-positive test result. Harms of diagnostic procedures include complications of prostate biopsy, such as pain, hematospermia (blood in semen or ejaculate), and infection. Approximately 1% of prostate biopsies result in complications requiring hospitalization. The false-positive and complication rates from biopsy are higher in older men. Adequate evidence suggests that the harms of screening and diagnostic procedures are at least small.

Generally a competent urologist can perform a biopsy, especially is MRI/US guided with 20+ cores in a manner to have a high sensitivity and specificity and do so with limited discomfort and if prep is proper then the chance of infection can also be minimized. The problem remains on determining the aggressiveness of the lesion. Even a 3+4 Gleason may genetically become aggressive.

I would argue that the data they use is still problematic at best. Proper PSA testing requires a long term annual at least measurement with percent free. From that one can obtain velocity which is essential. Also family history is essential. Then using Bayesian methods one can reasonably approach the patient. The literature referenced was not where close to such a protocol, testing was spotty at best as we have noted before. The results from a decade ago as we had demonstrated reflected in our opinion a fatally flawed test. The measurements were no annual at the very least, and as one delays testing an aggressive form may take over and eliminate any advantage.

 There needs to be a good clinical study where PSA is measured on a more frequent basis. The problem we face is that PCa can be genetically diverse and at one extreme, the dominant one, we have a relatively indolent disease. At the other extreme, we have a very aggressive type, which progresses very quickly. In doing any statistical analysis one must examine the results from both sets separately and thus one must perform more frequent PSA especially on this subgroup. In my opinion that is the basis of a fatal flaw.