I adopted my purebred beagle in 2020, not sure her age but she was just Dx’d with cancer of the spleen

It’s not official, we didn’t do a biopsy or even a chest X-ray, but ultrasound showed a 2cm mass in her spleen. On paper, she is 12, but I suspect maybe older. She’s a rescue. Perfect tri color coat, white feet and white tail tip. Perfect breeders dog. Had a litter just prior to adoption. Very well trained.

She developed sundowners about 4 years ago and we’ve kept it at bay with senilife which she responds to very well. A few months ago, she started having shaky limbs and when our regular visit came around I mentioned it. She showed signs of tenderness in her back so we thought that was it. She maybe threw her back out doing to zoomies. We also did blood work. Prescribed some joint supplements and gabapentin, sent home. We were traveling for the 4th and sent her to a home sitter. In the meantime, we get the blood and urine back. High triglycerides, high protein in her urine and some chrystals. Also, she has lost about 5 pounds, while looking like she gained 5 pounds, no change in diet or exercise. About a week after getting back, she starts coughing so I decide to return for the follow up and suspecting kennel cough, but the vet spends about 2 hours examining her and offers an abdominal ultrasound, no cost. So sure, why not? Well, she finds a 2cm mass in her spleen. This coincides with her back pain, and now I’m suspicious that the cough is from the mass spreading to her lungs. The shaky limbs aren’t getting better, and (my opinion only) I suspect it’s because the mass may have spread to her spine. I understand this could be a very aggressive form of cancer with rapid decline and potential very dramatic end, which I’d like to avoid. I just don’t know how long to expect. We arent going to treat, she’s an old dog hanging on a thread. Chemo isn’t going to be handled well. I had a white shepherd who was diagnosed at 9 with lymphoma. We were told 2 months and in less than 2 weeks I was lucky to carry her out of my house to the vet for euthanasia with some assistance from her and my sister. If she had died at home I don’t know how I would have gotten her out. She is still comfortable, but my husband will be traveling for a week soon and I guess I worry she will go downhill fast and I will have to deal with it on my own. Any idea how long we have? I think the shaky limbs started about 3 months ago, I thought it was old age.

Edit to add, she started leaking urine about a year ago. Just a a couple drips when she was on her way to potty sometimes. Now sometimes it’s a full small,puddle. She had no idea it’s happening. I previously thought it was the old age/ dementia, but the vet questioned it extensively. My last dog was also a beagle, and he started doing this a couple years before we put him down at 20, turns out he had undiagnosed bladder cancer.

EIDT #2: I think she had a seizure one day since coming home, I caught it out of the corner of my eye and then it was over. Also, she had always had major a reverse sneezing problem that was solved with the removal of most of her teeth. Her gums are pink now, but she is having crazy reverse sneezing a lot again.