Google University can open up a whole can of worms - most of it not applicable. However there are some decent scientific papers available that can help a little. To quote one
" Finding node-positive prostate cancer after a radical prostatectomy often leads to high postoperative prostate-specific antigen levels and is overall a poor prognostic factor. However, this does not necessarily translate into poor survival for all men. Management can be tailored to the severity of disease and options include observation, androgen deprivation therapy, and/or radiotherapy."
Note the first sentence - often leads to high PSA after the operation. That's why I said that your first PSA was good news.