I am not surprised to hear this news about the tumor, but also very sorry that yet another major challenge - and major decision - may now be facing you. Through the years, we've had members who have undergone a variety of treatments for enlarging macrotumors. Initially the only option here in the U.S. was the prospect of over a dozen traditional radiation treatments over the span of a month, with general anesthesia required for each procedure. Over time, more specialized options have been introduced in some centers, including cyberknife-type treatment that only requires a very few sessions, and also actual surgery. Returning to Dr. Bruyette, he helped pioneer successful canine surgery as a joint effort between UCLA and Cedars-Sinai Hospital in L.A. One of our very own members, Lucy, was his first patient in that pilot program, and I believe surgeries are still bring done there on select patients. Here are some write-ups:
http://dogaware.com/articles/newscushingssurgery.html
https://www.cedars-sinai.edu/Researc...st-Friend.aspx
We've also had members who have received advanced treatment at UC Davis and Washington, among other centers. I think Florida may also offer advanced options, as well. As you might expect, results have been variable. Some dogs have had very good responses and remained neurologically improved for an extended period of time. Some have not. Some have had an extended respite from Cushing's treatment. Others have had to continue with Cushing's treatment even though the tumor size was reduced enough to relieve neurological symptoms. I think a lot will depend on the actual location and dimension of the encroachment, as well as the vets' assessment of Yogi's overall viability as a treatment candidate.
Age may be a factor in his candidacy and also your decision. I'm guessing he may now be eleven. I've not had either of my two retrievers (Labs) reach twelve, with or without Cushing's. So one consideration may be the length of his expected lifespan, even with successful treatment. In other words, would he really have enough quality time left to gain from an invasive intervention. However, on the flip side, if he could benefit substantially from 2-3 cyberknife sessions and affordability was not an issue for you, then maybe that would be a worthwhile option.
I'd say, let's see how the actual MRI report reads, and then see what your vet recommends. And then we'll be here to talk over all your options.
Marianne