Bone cancer in dogs refers to the most common bone tumor among dogs. Bone cancer is 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 a tumor can metastasize or move from one body part to another. Bone cancer is a tumor that arises from the abnormal production of cells. Abnormal cell production resulted from an imbalance between bone-forming and bone-dissolving cells. Osteoblasts are bone-forming, and osteoclasts are bone-dissolving cells. Bone cancer in dogs mainly affects long bones of the body, e.g., arms and legs. Other bones, e.g., the jaw, hips, and pelvis, are also affected by bone cancer. At the same time, non-bony tissues like mammary glands, spleen, kidney, and liver are also severely affected due to bone cancer in dogs.
Etiology of bone cancer in dogs
The actual 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, resulting in a new bone. Osteosarcoma starts due to changes in healthy bone DNA. As a result of these changes, the cell begins 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., Paget’s disease and fibrous dysplasia
Males are more prone to bone cancer. Long dog breeds also tend to develop bone cancer. Some evidence suggests that dogs undergoing an orthopedic surgical implant procedure 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 your dog’s current situation with a veterinarian specializing in oncology. The veterinarian will guide you through 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 diseases such as arthritis.
Limb-sparing procedure– Limb-sparing involves the removal of that portion of bone that contains the tumor without affecting the entire limb. As compared to amputation, limb-sparing is more challenging to perform. Limb-sparing is more expensive and also requires a more extended recovery period. Limb sparing is performed in conjunction with radiation therapy. The biopsy results help to decide which type of additional therapy is needed. 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 the 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 in competing 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.
The osteosarcoma vaccine consists of modified bacteria using cancer immunotherapy to treat dogs with osteosarcoma.