Stage 3 Melanoma in Dogs: What Can We Do Next? | Dr. Nancy Reese Q&A 

So glad to be of service! As for mandibulectomy, that is such a nuanced decision, and so much depends upon the case, the skill of the surgeon (their confidence in handling that case), lifestyle factors, and, as you mention, the likelihood it will spread. The calculation in the end is this: if there is an oral melanoma in the body, it is probably going to metastasize at some point, and may have already done so. Removing it can help treat any local pain that might be there (if you've ever had a toothache, you can imagine the pain that MIGHT be present), and also eliminate that tumor as a source of metastasis. However, it may have already spread, in which case you're not preventing metastasis that has so far been undetected. So if you can afford the surgery and also deal with the aftercare, it's time to ask the surgeon who is comfortable doing the surgery questions like "about how much time will this get us?" and "is it possible there is undetected spread, and if so, is this going to help prevent more of that?" and "what would be the pros and cons of doing this surgery?" By asking questions about their thinking, you'll gain plenty of insights into what might or might not be helpful for your dog.