Osteosarcoma is a highly aggressive form of bone cancer commonly found in large breed dogs. It predominantly affects the long bones and poses significant health risks due to its rapid growth and potential to metastasize. This article provides an overview of osteosarcoma in dogs, highlighting its basic knowledge and importance for pet owners and veterinarians.

What is Osteosarcoma?

Osteosarcoma (OSA) is a malignant tumor that originates in the bone. It is the most common type of primary bone cancer in dogs, accounting for over 85% of all skeletal tumors. This cancer primarily affects the long bones, such as the femur, tibia, and humerus, but can also occur in other bones or even soft tissues.

Risk Factors

Several factors contribute to the risk of developing osteosarcoma in dogs:

• Breed: Large and giant breeds like Great Danes, Rottweilers, Greyhounds, and Saint Bernards are more susceptible.
• Age: Typically affects middle-aged to older dogs, with a peak incidence around 7-9 years.
• Gender: Males are slightly more prone than females.
• Previous Bone Injuries: Previous fractures or bone infections can increase the risk.

Symptoms of Osteosarcoma

Early detection of osteosarcoma can be challenging due to its subtle symptoms. Common signs include:

• Lameness: Sudden or intermittent lameness in the affected limb.
• Swelling: Noticeable swelling or a mass on the limb.
• Pain: Pain and discomfort, which may cause the dog to be less active or reluctant to walk.
• Fractures: Pathological fractures can occur due to the weakening of the bone by the tumor.

Diagnosis

Diagnosing osteosarcoma involves a combination of clinical examination and diagnostic tests:

• Physical Examination: A thorough physical exam to identify signs of pain, swelling, or abnormal growths.
• X-rays: Radiographs of the affected limb to visualize bone changes and identify the presence of a tumor.
• Biopsy: A definitive diagnosis requires a biopsy, where a sample of the tumor is taken and examined microscopically.
• Advanced Imaging: CT scans or MRIs may be used to assess the extent of the tumor and check for metastasis.
• Blood Tests: Blood work to evaluate the dog’s overall health and check for markers indicative of cancer.

Treatment Options

The treatment of osteosarcoma typically involves a combination of surgery and adjunct therapies:

• Surgery: Amputation of the affected limb is the most common surgical treatment. It removes the primary tumor and alleviates pain.
• Limb-Sparing Surgery: In some cases, limb-sparing surgery is performed to remove the tumor while preserving the limb.
• Chemotherapy: Often used in conjunction with surgery to target any remaining cancer cells and reduce the risk of metastasis.
• Radiation Therapy: May be used to manage pain and control tumor growth in cases where surgery is not feasible.

Prognosis and Importance

Osteosarcoma is a severe and life-threatening condition. The prognosis depends on several factors, including the stage of the disease, the location of the tumor, and the dog’s overall health. Early detection and aggressive treatment can improve the quality of life and extend survival time. However, due to the aggressive nature of osteosarcoma, long-term prognosis remains guarded.

Understanding osteosarcoma in dogs is crucial for timely diagnosis and effective treatment. Regular veterinary check-ups and being aware of the symptoms can help in early detection. If you suspect your dog may have osteosarcoma, consult with your veterinarian promptly to explore the best treatment options available.