Types of Cancer
Bone cancer in cats is more commonly reported in males, and the hind limbs are twice as much at risk than the front. Osteosarcoma is the most frequently diagnosed. It is a primary bone tumor, that is, it originates from the bone. Osteosarcoma is an aggressive bone tumor that will spread throughout the cat's body. However, it has a slow metastatic rate and survival can be expected with a complete removal of this cancer.
Fibrosarcoma is the second most common type of bone tumor, though still exceedingly rare in comparison to osteosarcoma. A primary tumor as well, these are locally aggressive and generally do not spread until the tumor is of high grade. It often arises from connective tissue and its cause is largely unknown.
Chondrosarcoma occurs least frequently of the primary bone tumors, and usually occurs singularly. It is not an aggressive form that can be treated often with surgery.
When a cancer originates in another part of the body then migrates to the bones, it becomes known as metastatic. This is usually seen with osteosarcoma, but metastatic bone tumors in cats are rare.
Symptoms of Bone Cancer
The first clinical sign of cancer is lameness in the affected limb. At first it may be subtle, but then will progress. This lameness will be unaffected by most treatments, particularly anti-inflammatory medication. The limb may also swell and the cat may be witnessed limping. Cats with cancer will be in pain, though with their stoic nature they may hide it. Other symptoms can include loss of appetite followed by weight loss.
The Diagnosis and Treatment
Diagnosing cancer is a several-step procedure that involves an extensive check up of the cat's bones, internal organs and blood. The process may look something like this:
- Chest x-rays to ensure the tumor has not migrated to the lungs.
- X-rays of the affected limb. Pelvic x-rays may also be included.
- A blood cell count and titer test to rule out other possible conditions
- A chemistry profile of the internal organs to check their functions, and a possible urinalysis.
- Nuclear scintigraphy or PET scan to rule out a macroscopic spread of the cancer.
- A biopsy if the bone tumor is suspected to be metastatic.
After this, most animals will be placed in surgery for amputation of the infected limb. Radiation therapy can sometimes play a role in treating any remaining cancer in the cat, but due to its slow metastasis, this is a case by case decision.
Cats have a much higher rate of survival when faced with cancer than do other animals, and most cats can be cured of it if the proper treatment is received soon enough.