I'm sorry to hear your news and don't have a definitive answer, but found myself in a similar situation five years ago. I was diagnosed with PD and then a few weeks later with breast cancer.
Because PD was in early stages, (and I was in denial anyway) I decided not to pursue any treatment for PD but just to deal with the cancer first. (Are you already on medication for PD or can you delay it?).
After operations, chemo, radiotherapy and recuperration, when the cancer seemed to have been dealt with, I knew it was time to deal with PD as symptoms had increased. I supppose my view is that it may be easier to deal with one at a time if that's an option for you.
I do know that if you're on PD medication it has to be handled carefully around operations due to anesthetic etc. Domperidone was prescribed during cancer treatment, and I also use this sometimes for nausea from PD meds, so this is one drug that appears useful for both.
I often thought that there could be better communication between my PD and cancer consultants and felt that I had to do a lot of work keeping each informed of my other "problem", so if you're able to set up some line of communicaion between them this may be helpful, especially around any conflicting treatment options, but I'd still recommend keeping each of them well informed yourself.
Wishing you well, and strength through this difficult time,
skatergirl