Before you do this, it's important to ask your comp structure. Are you straight salary? Production? A combination? If you increase your productivity by 20-30%, will your income increase in parallel? Because if there's nothing in it for you, don't do it.
As to "can you do it" the answer depends on you, but lots of us do it.
In my old job I did 60 min new, 15 min f/u and about 5% "extended" 30 min follow ups (complicated patients, treatment decisions, EOL discussions, etc). That was generally manageable for me after 2-3y, but could get hairy on a day of just follow ups where I wound up seeing 26-30 in a day, which is just more work than I care to do.
In my current job, I get 60 min for new cancers, 40 min for new benign heme (some of which turn into cancer) and 20 min for follow ups. I could easily switch to 15 min for f/u, but I like the flexibility that 20 min gives me, and not infrequently, I'll double book and wind up with 15 min/pt anyway. I could also easily change my new patient slots to 40 and 30, but again, choose not to for the flexibility it gives me. My current comp plan has a fairly high base (rural CAH and I'm currently the only oncologist) with a productivity bonus that I will easily exceed this year if things stay how they are.
I will also say that a lot of this depends on your support system in the office. If your MA can keep up with you, your schedulers don't have their heads up their arses and your nurses are largely self sufficient and have someone else to go to (NP or other physicians) for trivial things, then seeing 25-30 patients a day is not all that difficult. If those supports don't exist though, this will be painful for you.
Bottom line, if your employer is going to provide you the support to do this and pay you for it, and it's worth it for you, then yes, it's manageable. If they're not willing to do all those things then just say no.
