Osteosarcoma (bone cancer) is one of the most common tumor types in dogs. It usually develops in middle-aged or older large-breed dogs (although it increasingly occurs in younger dogs aged 2–3 years), especially in breeds such as Saint Bernard, Newfoundland, Great Dane, Pyrenean Mountain Dog, Cane Corso, and Bernese Mountain Dog, and it is more common in males.
Osteosarcoma is a type of tumor that usually originates on the bone surface and then spreads inward into the bone marrow. Unfortunately, the exact cause is still unknown.
Symptoms of osteosarcoma in dogs
The symptoms of bone cancer usually appear near the tumor site. This is typically around the limbs, ankles, and knees, but it can also occur in the ribs or nasal cavity. Symptoms vary depending on the tumor’s location. There may be bone enlargement or visible swelling, joint pain and lameness if the limbs are affected, or sneezing, nosebleeds, and difficulty breathing if the nasal cavity is involved.
Why early detection is important
Many owners mistake early lameness or swelling for an injury and only take their dog to the vet later. However, osteosarcoma can progress quickly, so early diagnosis can make a meaningful difference. The sooner examinations and treatment begin, the better the chances of improving comfort and quality of life.
Treatment of osteosarcoma in dogs
The effectiveness of treatment depends on several factors, including how deep the tumor is located in the bone and whether it has already reached the bone marrow.
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The most effective method of treating osteosarcoma is surgical removal of the affected area. Usually, the affected limb must be amputated, although in rare cases, a smaller, local procedure may be sufficient depending on the location and size of the tumor.
The success of surgery depends not only on the procedure itself but also on how effectively the dog’s immune system can respond to microscopic tumor cells and potential metastasis. While surgery can significantly reduce pain and tumor burden, in many cases it does not lead to complete recovery on its own, as osteosarcoma has a high tendency to recur or spread over time.
Chemotherapy is often used as an additional treatment after surgery in dogs with osteosarcoma, primarily to help slow disease progression and delay metastasis rather than to achieve a cure. Radiation therapy may also be considered, especially for pain control when surgery is not an option. While these treatments can significantly improve comfort and survival time, they are generally part of a disease-management approach rather than a definitive cure.
Long-term outcomes are strongly influenced by how well the body and immune system can support recovery and help control remaining tumor cells.
How long can a dog live with osteosarcoma?
The prognosis of osteosarcoma depends on many factors: the tumor’s location, treatment options, and the dog’s overall health. Without surgery and supportive therapy, the average survival time is only a few weeks to 2 months. With amputation, this increases to 3–6 months, and with chemotherapy combined with immunotherapy, it can extend to 9–12 months. While complete recovery is rare, the main goal is pain reduction and quality of life improvement.
The role of immunomodulatory therapy
A strengthened immune system is much less weakened by chemotherapy and radiation, and during recovery it better resists both internal and external infections and pathogens. A well-functioning immune system supports normal cellular surveillance and overall resilience during treatment. Therefore, immunomodulatory therapy is often considered during and after surgery as part of supportive care.
Although osteosarcoma often starts in one location, it is prone to metastasis and recurrence. Because of this, overall health status and supportive care can play an important role alongside veterinary treatment.
Based on practical experience, some dog owners and veterinarians choose to combine conventional treatment options (such as surgery, chemotherapy, or radiation) with supportive immunomodulatory approaches. Products like K9 Immunity™, K9 INU®, or similar supplements are commonly used with the aim of supporting immune function, treatment tolerance, and overall quality of life alongside standard care.
Osteosarcoma and strengthening the immune system
Supporting the immune system is crucial in all diseases involving immune dysfunction, such as lymphoma, dog brain tumor, mast cell tumor, hemangiosarcoma, or mammary tumor. Until the disease is brought under control, treatment often focuses on pain management, slowing progression, and supporting quality of life. In many cases, long-term outcome depends on a combination of medical intervention, overall health status, and supportive care.
Many veterinarians emphasize that long-term outcomes often depend on the dog’s overall condition and immune resilience. Even when treatment reduces tumor burden, supportive care remains important for maintaining quality of life and helping the body cope with therapy.
Since the cost of chemotherapy, radiation, or surgery can be very high, we are often asked whether medicinal mushrooms alone might be sufficient.
Therefore, whenever possible, it is generally advisable to reduce tumor burden first using conventional medical approaches such as surgery. This can help relieve physiological stress on the body and may support recovery when combined with targeted immunomodulatory support (e.g., K9 Immunity™, K9 INU®, K9 INUFactor®, K9 INUExtra®) as part of a broader supportive care strategy.
Whatever path you take, whatever decision you make, always discuss it with your veterinarian!
Tips for owners: how can you help your dog?
Alongside treatment, everyday care is very important. Provide your dog with a comfortable bed, easy access to water, and a nutritious diet. Always consult your vet about pain management. Love, patience, and a calm environment not only improve your dog’s wellbeing but also strengthen its immune system and resilience.
- Avoid overexertion: limit climbing stairs, jumping, and long walks. Opt for shorter, gentler activities to avoid unnecessary stress on the bones.
- Regular check-ups: since the tumor can progress quickly, veterinary visits are essential to detect recurrence or metastasis in time.
- Immune system support: in addition to diet, give immune-boosting supplements (e.g., medicinal mushrooms, specialized formulas) to help the body fight tumor cells.
The importance of proper diet in dogs with cancer
Cancer is one of the leading causes of death in dogs. Several recent studies confirm that healthy nutrition plays a role in the prevention of cancer. For example, recent publications have shown that many owners switch to more nutritious, energy-dense foods and supplements in order to improve quality of life for dogs diagnosed with cancer. Kramer et al., 2023 – Changes in diet and supplement use in dogs with cancer.
Many dogs are fed primarily grain-based kibble, despite their evolutionary background as meat-oriented animals. While dogs are able to digest carbohydrates to some extent, their metabolism is better adapted to diets rich in high-quality animal protein and fat.
If a diet is poorly balanced or relies heavily on low-quality carbohydrates, nutrient utilization may be suboptimal over time. In the long term, inadequate nutrition can place additional strain on the immune system, which may contribute to a higher vulnerability to chronic diseases, including cancers such as osteosarcoma.
If poor nutrition really contributes to the development of bone cancer in dogs, then conscious feeding becomes even more important. For a dog with cancer, it is not just recommended but almost mandatory. A carefully chosen diet can be one of the most important elements of successful treatment and a better quality of life.
Your dog’s body needs real, easily utilized nutrients to fight the disease. Just because a food is expensive, trendy, or widely recommended does not mean it is the best choice. A conscious, well-considered decision about diet can even save a life.
Read our related articles: Nutrition for dogs with cancer, and the Hungarian version: Read our article in Magyarul.
Risk factors and prevention
The exact cause of osteosarcoma is unknown, but certain factors increase the risk: large and giant breeds, rapid growth, genetic predisposition, and previous bone injuries. While complete prevention is not possible, a proper diet, regular veterinary screenings, immune-boosting supplements, and a balanced lifestyle can help make the dog’s body more resilient.
Frequently asked questions about osteosarcoma in dogs
❓ What is osteosarcoma in dogs?
Osteosarcoma is a malignant tumor that originates from the bone, most often in the limbs, and quickly metastasizes.
❓ What are the symptoms of bone cancer in dogs?
The most common symptoms are lameness, bone swelling, pain, nosebleeds, or sneezing. Symptoms depend on the tumor’s location.
❓ Which dog breeds are prone to osteosarcoma?
Mainly large breeds such as Saint Bernard, Newfoundland, Great Dane, Pyrenean Mountain Dog, Cane Corso, and Bernese Mountain Dog.
❓ How long can a dog live with osteosarcoma?
Without treatment, only a few weeks to 2 months. With amputation, 3–6 months, and with combined therapy and immunomodulation, up to 9–12 months.
❓ Can bone cancer in dogs be cured?
Complete recovery is rare. The goal is to reduce pain, slow the disease, and support the immune system for longer survival.
❓ Is amputation recommended for dogs with osteosarcoma?
Amputation is the most common and effective treatment. It reduces pain, relieves the body, and can extend the dog’s life.
❓ What treatment options are available for canine osteosarcoma?
The most common treatment is limb amputation. As additional options, chemotherapy, radiation, and immunomodulatory supplements may also help.
❓ How can I help my dog at home?
Provide a comfortable resting place, gentle exercise, a nutritious diet, and immune-boosting supplements. Regular veterinary check-ups are essential.
For more information, you can read our article on nutrition for dogs with cancer, as well as our overview of tumor symptoms in dogs. In addition, you can learn how medicinal mushrooms can also support cancer treatment, and moreover, you may browse our wide range of immune-boosting supplements for dogs.
More about dog cancers
Important: This article is for informational purposes only and does not replace veterinary examination or treatment. For an accurate diagnosis and the right therapy, always consult your veterinarian.
References:
- Culp, W. T. N., Olea-Popelka, F., Sefton, J., Aldridge, C. F., Withrow, S. J., Lafferty, M. H., Rebhun, R. B., Kent, M. S., & Ehrhart, N. (2014). Evaluation of outcome and prognostic factors for dogs with appendicular osteosarcoma surviving 1 year or longer. Journal of the American Veterinary Medical Association, 245(10), 1141–1146.
- Boston, S. E., Ehrhart, N. P., Dernell, W. S., Lafferty, M. H., Withrow, S. J., & Rao, S. (2006). Evaluation of survival time in dogs with stage III osteosarcoma: 90 cases (1985–2004). Journal of the American Veterinary Medical Association, 228(12), 1905–1908.
- Szewczyk, M., Lechowski, R., & Zabielska, K. (2015). What do we know about canine osteosarcoma treatment? – review. Veterinary Research Communications, 39(1), 61–67.
- Cornell University, College of Veterinary Medicine. (n.d.). Osteosarcoma in dogs. Riney Canine Health Center.
- Simpson, S., Dunning, M. D., de Brot, S., Grau-Roma, L., Mongan, N. P., & Rutland, C. S. (2017). Comparative review of human and canine osteosarcoma: morphology, epidemiology, prognosis, treatment and genetics. Acta Veterinaria Scandinavica, 59(1), 71.
- Selvarajah, G. T., Kirpensteijn, J., van Wolferen, M. E., Rao, N. A. S., Fieten, H., & Mol, J. A. (2009). Gene expression profiling of canine osteosarcoma reveals genes associated with short and long survival times. Molecular Cancer, 8, 72.
