Bone Tumors in Dogs

Bone tumors in dogs may be malignant or benign. However, over 80% of bone tumors are malignant. These tumors are known as osteosarcoma and will have an aggressive evolution. Bone tumors are more common in giant canine breeds that are over the age of 8. The tumor can quickly extend to other areas of the dog’s system and affect the lungs or the neighboring lymph nodes.

Causes of Bone Tumors

Bone tumors are more common in senior, male, giant breed dogs. This can mean that the causes of tumors may be genetic. However, the exact causes of bone tumor formation are not known. There are also some theories that claim the tumors occur due to toxic environments, diet or frequent bone injuries.

Symptoms of Bone Tumors

The symptoms of bone tumors will depend on the size and location of the tumor. If the tumor is benign, small and is not located near any joints, this may not produce any symptoms. However, if the tumor is larger and malignant, this can cause a number of symptoms:

  • Limping or difficulties when performing certain movements, depending on where the tumor is located
  • Licking or biting the area where the tumor is located, especially if the tumor caused pain
  • Visible swellings on certain areas of the body (i.e. a limb or back)
  • Swollen joints, if the tumors are located close to joints
  • Increased sleep hours
  • Lethargy
  • Lack of appetite
  • Depression

Diagnosing Bone Tumors

A bone tumor cannot be diagnosed based on the symptoms alone. The symptoms may be indicative or rheumatoid arthritis or a different joint and bone conditions.

Consequently, x-rays must be performed to detect any tumors. A biopsy will have to be performed on a sample from the tumor, to determine if the growth is cancerous. If the biopsy shows that the tumor is malignant, the vet will also perform additional investigations to establish the stage of cancer. The stage of the cancer is important when determining the best course of treatment.

Treating Bone Tumors

The treatment will vary according to the nature of the tumor. If the dog has a benign tumor, this will rarely develop and may not need any treatment. However, if the tumor is close to joints and makes movement difficult, the tumor will have to be removed. Surgery is also the first choice treatment option if the tumor is malignant and is during the first stages of development, not involving other organs. The tumor will be removed, but the dog will have to receive additional treatment (i.e. chemo drugs) to hinder the development of the cancerous cells. If the tumor is very large and has affected other organs in the dog’s system, surgery may not be possible and the bone cancer may be fatal. The cancer is aggressive and the dog may not live more than 2 to 6 months, not even if he receives medication treatment. Pain management is essential during the last stages of bone cancer.