What happens if a dog gets bone cancer?

Bone cancer usually causes lameness, painful whining, swelling and sensitivity of the affected limb, lethargy, fractures at or near the tumor site, loss of appetite, breathing difficulty, and increased nasal discharge. If the cancer is in the leg, amputation is usually needed to control it, along with long-term chemotherapy and radiotherapy.

Because cancer spreads very easily, if it has reached the lungs it can cause breathing difficulty, so additional treatments are required.