If you have a dog, you most likely have seen them limp or refuse to put weight on a foot at some point. Dogs run, jump, and sometimes take a risky tumble, leaving them a bit stiff for a day or two. Most of the time, a quick vet visit brings reassurance that it’s nothing but a tweak. Unfortunately, that’s not always the case. For some dogs, what causes a limp or limb pain can be much more serious than a fall in the yard or stumbling off the sofa; it could be cancer.
While many dog owners never even want to think of a cancer diagnosis for their furry friend, it’s important to be aware of the subtle signs that a tumor could be affecting your dog’s bones. In this blog, we’ll cover the basics of osteosarcoma in dogs and share what aspects of the disease owners should be prepared for to keep their dogs happy and comfortable for as long as possible.
What Is Osteosarcoma in Dogs?
Osteosarcoma is an aggressive but common form of bone cancer in dogs, accounting for approximately 85% of all bone tumors in dogs. Often mistaken for a simple limp or minor injury, this aggressive cancer can weaken bones, cause excruciating pain, and spread throughout the body before owners even realize something is wrong. This bone cancer can affect any type of dog of any age; however, it most commonly affects middle-aged to senior dogs, and some breeds are predisposed to developing it.
Large and giant breed dogs – weighing over 50 pounds – are most commonly affected by dog osteosarcoma due to genetic, anatomical, and developmental factors. The breeds that carry the highest risk of developing osteosarcoma include:
- Great Danes
- Irish Wolfhounds
- Rottweilers
- Greyhounds
- Saint Bernards
- Bernese Mountain Dogs
- Golden Retrievers
- Labrador Retrievers
- Doberman Pinschers
- German Shepherds
These large breeds often develop very quickly as puppies, sprouting long limbs and growing into those adorably large feet. However, along with this rapid growth, cellular turnover also increases, allowing for potential mutations and variations in bone cells. These mutations can occur thanks to hormonal changes as well as cell divisions while these dogs are growing longer bones. While these are considered normal processes in a dog’s development and growth, if mutations or deviations occur, they can ultimately increase the chance of tumor formation.
The ulna, radius, femur, and tibia – some of the longest bones in a large dog’s body – are the areas most commonly affected by osteosarcoma, as osteosarcoma in dogs is more likely to affect the limbs, as opposed to the skull, spine, or ribcage. In addition to the potential for tumor growth during a dog’s early development, large dogs also carry a higher risk for the development of osteosarcoma due to the additional strain that is placed on these long bones due to the dog’s size and stature. This strain can often result in microfractures, or small cracks in a dog’s bones, that can lead to decreased bone health and stability, as well as malignant changes in a dog’s overall bone tissue.
What Are The First Signs Of Osteosarcoma In Dogs?
Osteosarcoma in dogs can be challenging for owners to recognize, as early signs of the cancer are very subtle and can mimic other conditions like arthritis or minor limb injuries, which are not nearly as urgent.
Some dogs may not even show signs of osteosarcoma until the disease has progressed and the presence of the tumor begins actively causing the dog pain. Because tumor growth for dog osteosarcoma begins within the bone, dogs may not start limping or showing visible signs of swollen or fractured limbs until the tumor has been allowed to grow, and potentially spread to other parts of the body.
General Symptoms Of Osteosarcoma In Dogs Include:
- Lameness or limping
- Loss of muscle mass
- Swelling
- Localized Pain
- Fractures
- Lethargy
- Weight loss
- Respiratory issues resulting from tumor growth or pain
If your dog is showing any of these signs, taking them to the vet for a checkup is always the best course of action. Veterinarians will most commonly use X-rays, physical exams, biopsy, and sometimes CT scans to confirm the presence of a tumor and to determine the extent to which it has grown or spread.
If your dog does receive a diagnosis of osteosarcoma you and your veterinarian can work quickly to begin treatment to prolong your dog’s life, and if it comes back as something else or nothing at all, you and your dog can rest easy and follow whatever recommendations your veterinarian has for their specific condition. After all, when it comes to your dog’s health, it’s always better to be safe than sorry!
Available Treatment Options for Dog Osteosarcoma
Unfortunately, there is no cure for osteosarcoma in dogs and the prognosis for dogs diagnosed with the cancer is generally poor. However, that doesn’t mean there aren’t options for treatment and prolonging a dog’s life in the short term.
Veterinarians and researchers have developed a variety of approaches to treating bone cancer in dogs ranging from pain management techniques to chemotherapy. Your veterinary care team will recommend a treatment plan for your dog based on their age, health status, and the location and size of their tumor, while also considering if the tumor has spread or if other secondary medical complications have arisen.
Depending on your dog’s specific circumstances, your veterinarian may recommend treatments including:
- Amputation – Removal of the limb affected by the primary tumor is commonly used as a pain management strategy to eliminate a dog’s discomfort and improve their overall quality of life. For dog owners, it’s important to understand that limb removal via amputation does not cure or eliminate the cancer; it should instead be seen as a tool to help your dog live out the remainder of its life in as little pain as possible. Rest assured that many dogs adapt well to life after amputation and can be just as happy with three legs.
- Limb-Sparing Surgery – In some situations – such as when dogs have arthritis or neurological conditions and may not thrive while missing a limb – limb amputation is not recommended, and limb-sparing surgery can be performed instead. As opposed to removing the entire limb, limb-sparing surgery involves removing only the affected bone and replacing it with a bone graft or alternative implant. Because this surgery involves replacing lost bone, it does carry a risk of infection and implant failure; however, your veterinarian will be able to assess if your dog is a good fit for this procedure.
- Chemotherapy – Chemotherapy has been used to slow the progression of osteosarcoma in dogs, allowing them to spend a little more time with their owners. While chemotherapy in humans is typically viewed as a frightening and side-effect-ridden undertaking, dogs tolerate chemotherapy surprisingly well, typically only showing mild side effects like lethargy and nausea after treatment.
- Palliative Radiation Therapy – In cases where surgery and amputations cannot be performed, some veterinarians may recommend radiation therapy as part of a pain management plan. Radiation therapy can help reduce pain and inflammation at the tumor site, helping your dog be more comfortable.
- Pain Management & Palliative Care – Some owners may choose not to have their dog undergo surgery or chemotherapy. In these cases, veterinarians will put together a pain management plan utilizing medications such as NSAIDs, opioids, and bisphosphonates to ease a dog’s pain as owners prepare to say goodbye.
How To Prevent Osteosarcoma In Dogs
While pet owners with large and giant breed dogs may be seeking out information about how to prevent their dogs from developing osteosarcoma in the first place, it is, unfortunately, a fruitless search, as there is currently no known way to prevent osteosarcoma in dogs. The anatomical, developmental, and genetic factors that contribute to osteosarcoma in these dogs cannot be changed, leaving veterinarians and pet owners alike unable to stop initial tumor development from occurring. The best recommendations the veterinary community currently has are keeping your dog at a healthy weight to avoid unnecessary bone strain, avoiding fractures and other bone injuries as best as possible, and avoiding unnecessary implants or radiation treatments for previous injuries.
While this bone cancer in dogs can’t be prevented, that doesn’t mean pet owners have to sit by helplessly and wait for a late-stage diagnosis. In fact, early detection and diagnosis of osteosarcoma in dogs can be a real game changer for a dog’s prognosis, as many of the available treatment options for osteosarcoma are more effective in the earlier stages of the cancer.
To help sniff out any signs of danger and catch dog osteosarcoma as early as possible, be sure to take your dog to the vet for their regular wellness visits, and don’t be afraid to speak up and be candid with your vet if you notice any concerning behavioral changes or the emergence of any new symptoms.
Final Stages Of Osteosarcoma In Dogs
Because osteosarcoma in dogs is an aggressive disease that often progresses rapidly, pet owners need to know what will happen next for their dog and what to expect at the end of their dog’s life.
In most cases, the “final stages” of osteosarcoma occur when the cancer has metastasized to other parts of the body and has led to severe pain or damaging systemic effects within the dog’s body. In advanced cases of osteosarcoma, pet owners should be ready to face the following challenges:
1. Severe and Persistent Pain: As the tumor grows and the cancer progresses, some dogs may reach a point where the affected limb or area becomes extremely painful despite medication and pain management efforts. This can lead to distressed vocalizations, reluctance to move the affected limb, and noticeable displays of pain or discomfort when the affected area is touched.
2. Increased Lameness or Inability to Walk: Due to the intense pain, dogs may completely stop using the limb, dragging it, or holding it off the ground when they are attempting to walk or move. If amputation or surgery were not performed on the dog prior to this stage, the tumor may have compromised the bone’s structure leading to a great risk of fractures.
3. Significant Swelling and Tumor Growth: When the cancer has progressed, owners may notice severe swelling or deformity caused by the tumor. These visible effects on the dog will continue to worsen the longer the cancer is allowed to grow and spread.
4. Metastasis – Cancer Spread to the Lungs or Other Organs: When the cancer spreads to other parts of the body, different organs and bodily systems can be negatively affected. For example, if the cancer spreads to the lungs, the dog may exhibit respiratory distress or difficulty breathing.
5. Decline in Quality of Life: One of the most difficult things that owners of dogs with osteosarcoma grapple with is watching the quality of their dog’s life deteriorate. As the cancer progresses, treatment and pain management techniques may become less effective, leaving the dog uncomfortable and in pain, with little desire to engage in activities they used to love.
When to Consider Euthanasia for Dog Osteosarcoma
No dog owner ever wants to think about losing their best friend, but for many owners of dogs with osteosarcoma, the choice of euthanasia may be inevitable to keep their dog from any unnecessary suffering.
Euthanasia is often the most compassionate choice for dogs suffering from the effects of the cancer’s late stages. While treatment and pain management can be given, it’s important for owners to remember that these are tools to help dogs with this cancer maintain a good quality of life; despite the best efforts of owners and veterinarians alike, there may come a time when treatments are no longer effective, and a dog’s quality of life has decreased so much that it is unfair to allow their illness to continue.
Euthanasia may be the right choice if your dog is experiencing:
- Persistent, uncontrollable pain despite medication
- Difficulty breathing due to lung metastasis
- Loss of ability to walk or severe immobility
- No longer interested in eating, drinking, or interacting with loved ones
If you’re unsure, talk to your veterinarian! They are there to support you and make the best decision for your dog – even if it is a hard one.
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