[Blueface]

Been there.
Nearly three years ago, mine got the same thing.
Had him operated for nearly $2k and spent a crap load after that on follow up care.
Had him split half open from back to belly to remove the cancer.
Lab results came back that he had the worst level and it was likely to return.
In six months, it started to return.
Less than a year after surgery, had to put him down.
Only thing I never went for was the chemo. I made life as comfortable as possible but didn't do that to him.
In the end, no doubt I would do the same again.
Tough call.
Good luck.