My 12 year old Labrador was diagnosed with Osteosarcoma and was given a prognosis of 6 - 12 weeks left to live (we are at the 5 week mark) Due to severe arthritis it has not been possible to have his leg amputated so he is basically just on pain killers. I have been told that there is a 90% chance that the cancer will spread to the lungs and would like to know what kind of symptoms I should be looking for. He has started panting heavily and occassionally coughing but has not lost his appetite or any weight and seems very happy most of the time. I am at a bit of a loss as to what is going to "get him" in the next 7 weeks? And should I expect a sudden drop in his health or is it more gradual.
Thank you for your help.

