I interviewed with a couple of groups of "group practice" general urologists. Both groups did every oncologic case that they wanted, including partial nephrectomies, prostatectomies, and cystectomies. I'm not sure if they did RPLND and caval thrombi.. those don't come along all too often.
In my (academic) practice, my "diagnosis grid" is set up so I can see pretty much any oncologic case. My chairman has encouraged me to perform any case I feel like performing, even though I have several oncology partners. It has been my choice that I will evaluate and counsel patients on options for more complex surgical problems (partial nephrectomy, cystectomy) and will surgically manage anything else (orchiectomy, TURBT, etc). My oncologic partners will refer me TURBTs and prostate biopsies and such.
Residents often tell me they want to do an oncology fellowship so they can do the big oncologic cases. You don't HAVE to have a fellowship to do that stuff. You can make your practice whatever you want. But as cpants points out, in an academic practice with oncologists as partners, you might not be too busy with oncologic work.