Bone cancer in dogs refers to the most common bone tumor among dogs. The bone cancer commonly found in the larger breeds. This fatal disease is very aggressive and has the ability to metastasize. There are different treatment options available for bone cancer in dogs, but generally, the long term prognosis for the animal is poor. It’s an aggressive form of bone cancer that has an affinity to metastasize within the leg bones of large and giant-breed dogs.
What is bone cancer(osteosarcoma)?
‘Osteo’ means bone and ‘sarcoma’ means malignant tumors. So, the term osteosarcoma means malignant tumor of the bone. Malignant means tumor can metastasize or move from one part of the body to another. Bone cancer is a tumor that arises from the abnormal productions of cells. Abnormal cell production resulted from an imbalance between bone-forming and bone dissolving cells, respectively. Osteoblasts are bone-forming and osteoclasts are bone dissolving cells. Bone cancer in dogs mostly affects long bones of the body e.g arms and legs. Other bones e.g jaw, hips, pelvis are also affected through bone cancer. Whereas non-bony tissues like mammary glands, spleen, kidney, and liver are also badly affected as a result of bone cancer in dogs.
Etiology of bone cancer in dogs
The real cause of bone cancer in dogs is still not clear. According to doctors bone cancer in dogs forms when something goes wrong in the cells that are resulting in making a new bone. Osteosarcoma starts due to changes in healthy bone DNA. As a result of these changes, the cell starts making new bone when it isn’t needed. This resulted in tumor formation that can metastasize and destroy other healthy tissues of the body.
The factors that increase the risk of osteosarcoma are:
1. Previous radiation therapy treatment
2. Bone disorders e.g Pagets disease and fibrous dysplasia
Males are more prone to bone cancer. Long dog breeds also tend to develop bone cancer. Some evidence suggests that if a dog undergoes orthopedic surgical implant procedure they are also at risk of developing bone cancer.
Genetic disorders also increase the risk of bone cancer e.g hereditary retinoblastoma, Bloom syndrome, Li-Fraumeni syndrome, Rothmund-Thomson syndrome, and Werner syndrome.
Treatment of bone cancer in dogs
Treatment options– Discuss the current situation of your dog with a veterinarian who specializes in oncology. The veterinarian will guide you about the complete treatment plan. Treatment options for bone cancer in dogs include the following:
Surgical amputation– The most common treatment option is amputation. During amputation, the affected limb will be surgically removed. For a successful treatment, the remaining three legs must be strong enough to bear the workload. The sound limbs should be free of disease such as arthritis.
Limb-sparing procedure– The limb-sparing involves the removal of that portion of bone that contains the tumor, without involving the entire limb. As compare to amputation limb-sparing is more difficult to perform. Limb-sparing is more expensive and also requires a longer recovery period. Limb sparing performed in conjunction with radiation therapy. The biopsy results helps to decide which type of additional therapy required. Chemotherapy helps control the growth of any tumor cells. Tumor cells metastasize beyond the primary tumor site e.g the lungs and other bones. Radiation therapy eliminates remaining cells around the initial tumor site.
Chemotherapy– It can stop the growth of those cancer cells that have already spread at the time of diagnosis. Chemotherapy is ineffective to compete with primary cancerous growth. Dogs tend to tolerate chemotherapy far better than we do. They rarely experience significant hair loss, vomiting, and loss of appetite.
Other treatment options for bone cancer- Corticosteroids, NSAIDs, and anti-inflammatory drugs can provide some relief from pain. This is also an option for dogs who are not eligible for surgery.
Osteosarcoma vaccine– The vaccine consists of modified bacteria using cancer immunotherapy to treat dogs with osteosarcoma.