I'm sorry I haven't been a regular on this forum but it was very helpful to me in the early stages of Piper's diagnosis and pre- and post-amputation. Piper was a Golden Retriever, 7 years old when diagnosed with osteosarcoma Christmas Day 2019. She had her amputation January 14, 2020 and started chemo 2 weeks later. She did wonderfully - never missed a meal, was ambulatory from Day 2 and even learned quickly how to swim after balls again. We called her "The Amazing Piper" - she never let her handicap get in the way of enjoying life. She went for 3-monthly checkups to the oncologist, x-rays and check ups revealed no sign of mets. Then about a month or so ago, every now and again, but not often, she would have a short cough. I got a little concerned that maybe something was setting in, but she was never out of breath or energy (she initiated playtime with our 2-year old Golden more than the 2-year old did with her!). It wasn't every day, but she was due soon for her check up (my husband is a vet but I still bring her to the onco for check up and x-rays) so I figured we would see what was up. She went on December 31 and x-rays looked good - after a radiologist looked at them, she saw what might be a small nodule but also could have been an artifact so we decided to come back in a month rather than wait 3. I mentioned the cough but stressed that it was very occasional - the xrays certainly didn't see any cause for it. That Saturday, 2 days later, Piper became very anxious, like there was a thunderstorm coming but the weather was very clear. She was doing a little more of the coughing but not significantly and she ate dinner with no problem. Then that evening she just couldn't settle down and the hacking was worse. She couldn't sleep so around 2-3 AM I gave her a trazodone - something she has taken before for thunderstorm anxiety. Later that morning she was still collapsed but I thought it could be the effects of the trazodone -she was much calmer and just sleeping. I really didn't want to take her up to the emergency that day because they just would have hooked her up to fluids and put her in a cage. She didn't seem uncomfortable and she wasn't having trouble breathing. The coughing had stopped. But she clearly wasn't right. Later that afternoon, when it was clear she wasn't going to improve, we carried her downstairs and did bloodwork and took xrays of her throat and abdomen. Nothing remarkable. At that point she just got less and less responsive, and literally just slipped into what must have been a coma. She took her last breaths just before 11pm that evening. No seizures, no agony, just stopped breathing. My husband, who has been in practice for over 40 years has no idea, the oncologist has no idea what happened. I had even scheduled an ultrasound for the next day. I'm just mystified as to what could have taken her life so suddenly? Another tumor somewhere? Has anyone else had this experience? I thought we had more time since she was doing so well. Just looking for some answers, not that it will bring her back and not that I expect I will find any but it doesn't hurt to ask. Missing our Pipey-pipe.