I've seen two cases of this just recently.
One guy was several years after RP, and proudly saying his PSA was 0.7 (and 0.4 the year before) and his GP says it's fine as it's <3.0
Another where a guy has had a RP and his PSA is going 0.14, 0.16, 0.18, and his GP says nothing to worry about, again because it's a long way below 3.
I was in a meeting with a urology consultant and several patients last week, and one of my comments was most prostate cancer patients who are more than a month into their diagnosis will know more about prostate cancer than their GP. The consultant laughed and said how true.