That's an excellent question and you may get a variety of answers from this forum.

I see for the first two years the frequency was every three months, annually after that based on the first two years as undetectable. After that, you're medical team went to an annual basis.

That is consistent with AUA guidelines - https://uroweb.org/guidelines/prostate-cancer/chapter/followup
Part of that is your risk, Grade Group, the fact that your pathology report said high risk with positive margins, Perineural invasion and invasion into the neck of the bladder.

You could put your results into MSKCC PSADT nomogram to gain an idea of PSADT and PSAV.

There can be variations, unexplained in PSA testings. When my urologist switched to USPSA, first one came back at .326, I almost hit the panic, button, we tested again in two weeks and six weeks after that, both went down. Why, who knows.

I think the answer lies in you, are you and your medical team comfortable with say three months or given your risk factors, one or two...?

Another questions is does waiting three months carry a risk of change the outcome of your PCa and a treatment decision (doublet, triplet, will radiation be a part of it) - would it allow the PCa to spread such that a treatment decision may change versus one to two months. Given your risk factors, you may consider more frequent testing. Have you discussed with your medical team, what do they say.

More importantly is do you have decision criteria around what to do with the results...? Mine were, and are, three or more PSA increases spaced three months apart, PSA between .5-1.0. When the clinical data hits those decision points, we image and informed by the results, decide on treatment, what, for how long, criteria to come off treatment...

Ultimately the decision is yours. If your decision is different than what your medical team wants to do, remember, it's your decision and they are on your team to support you, write the damn order...!

If you ask what I think, well, three months at this point does not carry a risk of progressions such as your treatment options will change drastically if at all. You would not be wrong to ask for monthly or every two months. I think they answer may lie in what decision criteria you have for determining when to go on treatment and an important part of that is imaging which at .5 or higher (can be less though) can more and more locate recurrences.

One conundrum is treat too late or treat too soon. Another is treat too aggressively or not. Given your clinical history, the 2nd conundrum may be an easy choice when you decide to treat, aggressively!

Kevin