Two new studies below.
We are all beyond biopsies for initial diagnosis, but this subject drives me crazy.
We all know that PSA has poor specificity for PCa. Over the past 13 years, I have read countless papers showing that a panel of tests (the panels invariably include PSA) do much better.
It is clear that there is resistance to change. If there was anything good to say about the U.S. Preventive Services Task Force (USPSTF) recommendation against PSA–based screening, its that it should have resulted in another look at the panels. If the profession could eliminate over-detection & over-treatment, the USPSTF would have to reconsider.
Serious PCa can exist at low PSA levels (my PSA was 0.8 when a nodule was found via DRE). The cutoff for biopsy is simply designed to detect cancer in at least 20% of tested men. In other words, up to 80% of men with elevated PSA could avoid a biopsy if there was an accurate panel.
Urologists make money out of biopsies. To adopt a panel test (for which they would make no money) would be to cut biopsy income by up to 80%.
If a patient wanting to avoid an unnecessary biopsy, were to ask if there were other tests, the response might be: "Let's do a biopsy to make sure." And yes, the panels give a probablistic diagnosis.
But a biopsy is a sample. One might be told that there is cancer, but I doubt that many men are told that there is a x% possibility of the Gleason being downgraded & y% probability of being upgraded, after Pathology have looked at the extracted organ. I made my decision based on a firm Gleason score of 4+3.
In study [1] from Duke [Durham, NC]:
"Over half of contemporary clinical Gleason 8 on prostate biopsy are downgraded at radical prostatectomy."
"A total of 61.5% (91/148) of clinical HGS 8 diagnoses were downgraded on prostatectomy, with 58.8% (87/148) downgraded to Gleason 7 (Gleason 4 + 3 n = 59; Gleason 3 + 4 n = 28)."
13 years ago, I was told that it was probably pointless to have surgery with a GS of 4+4. How many men rushed into ADT with a faulty 4+4 diagnosis?
In study [2] from Nanjing, China, of cases diagnosed with Gleason 6:
"The rate of GS upgrade was 50.0% (23/46)."
Gleason score 3+3 cases are urged to opt for active surveillance. With a 25-30% progression rate (& a 50% chance of an upgrade), who can blame a man for rushing into treatment.
The 4Kscore test is commercially available. PSA is part of it. It, or something like it, will have to adopted at some stage. Medicare should insist on it before biopsy.
-Patrick