Heh, I think I posted about this before, but some guy in Texas had a poster at USCAP last year or the year before about how the quality of service at a (GU) pod lab was just as good as standard of care. His whole point was that the diagnosis of cancer was made in similar percentages (along the gleason spectrum) as nationally reported averages. That's rock solid evidence! 😉
In regards to taking prostates out based on bad diagnoses, most large hospitals (at least, academic ones) require review of outside diagnoses internally (as transfer cases) before the surgeons will operate. It doesn't always happen, of course, and mostly depends on the clinician requesting it to be sent. But one slip up and they never forget again. But on our rotations we see tons of transfer cases from outside labs, it's amazing to see the poor quality of a lot of material. There is one large megalab we see lots of cases from where the lab manipulates the slides and the cutting to put prostate cores from two different sites on the same slide, you differentiate them based on which part of the slide they are on and how they are inked. I guess if you are doing thousands a year every glass slide you can save helps, but it's also a little disturbing. I am sure that proponents of the system would be able to give you plenty of statistics on how effective they are, and even how their system improves results, but I'm still skeptical.