What is osteosarcoma in dogs? Explaining causes and symptoms

Like humans, dogs can suffer from a variety of illnesses.

Among these, this time we'll introduce osteosarcoma, a disease that is particularly dangerous to dogs.

What is osteosarcoma?

Osteosarcoma is a type of bone cancer (malignant tumor). Bone cancer can be divided into cancers that metastasize from cancers elsewhere and cancers that originate in the bone itself.

Osteosarcoma accounts for the majority of cancers that originate in the bone itself.

Causes of Osteosarcoma

Unfortunately, the exact cause of osteosarcoma is unknown.

In dogs, 75% of osteosarcomas are found in the bones of the front and back legs, and 25% in the bones of the trunk. Front legs are more likely to develop osteosarcoma, with incidence rates in the front legs twice as high as in the hind legs.

In the front legs, osteosarcoma is most likely to occur in areas far from the elbow (the humerus closer to the shoulder or the front leg closer to the wrist). In the hind legs, osteosarcoma is most likely to occur in areas closer to the knee (the femur or shin bone closer to the knee).

The reason is still unknown, but there are differences depending on the breed. Large dogs weighing over 40 kg are said to be at a particularly high risk of developing osteosarcoma.

Since the likelihood of developing this condition varies depending on the breed, it is thought that there may be a genetic factor.

The average age of onset is said to be 7 years old, but the likelihood of developing this condition peaks twice, once in young dogs and once in old dogs, and it can occur in dogs as young as 2 years old.

Symptoms of Osteosarcoma

Tumors are particularly likely to develop in the long bones of the legs, often accompanied by severe pain, resulting in swelling of the legs, an abnormal gait, and a limp.

If lesions occur in the spine, paralysis may occur.

Osteosarcoma is a malignant tumor that progresses rapidly and is prone to metastasis at an early stage.

Metastasis to the lungs is particularly common, causing symptoms such as shortness of breath.

〇 Be careful if you experience these symptoms!

The bone itself is weakened in the area where the tumor is located, making it less able to withstand stress.

For this reason, osteosarcoma may be discovered only after an injury has occurred.

Symptoms are similar to those of an early injury, but caution is required if symptoms persist.

• Painful to the touch
• Swelling or lumps in the bone area
• Strange gait
• Paralysis (if the disease affects the spine)
• Coughing or difficulty breathing (if the disease spreads to the lungs)

〇What the test reveals

X-rays often reveal abnormalities in the bones in the area of ​​pain or lumps.

When lung metastasis occurs, a chest X-ray may reveal a white shadow on the lung.

After Developing Osteosarcoma

The course of treatment varies depending on the location of the tumor, age, stage of detection, and type of treatment.

Without treatment, the average life expectancy is approximately 110 days.

Even if amputation is performed, it only extends life by about two months.

For this reason, amputation is sometimes combined with chemotherapy, which can extend survival by about 10 to 18 months.

Even with aggressive treatment, cancer often eventually spreads to the lungs, leading to death.

Osteosarcoma Treatment Methods

In most cases of osteosarcoma of the extremities, amputation of the foot is required.

Osteosarcoma is prone to metastasis, so even surgery can be difficult to completely cure.

To extend survival and relieve pain, chemotherapy with anticancer drugs, radiation therapy, and palliative care are combined.

Treatment at a Veterinary Hospital

1. Surgery (Leg Amputation)

To extend the dog's life and relieve pain, the affected leg is removed.

Resection is typically performed at the base of the leg, such as the shoulder or hip joint.

Heavy dogs, such as giant breeds, or dogs with joint disease may require assistance after surgery, but many dogs can walk on three legs.

2. Anticancer Drug Treatment

Medication is administered over the medium to long term while monitoring the patient's physical condition.

Using chemotherapy after leg amputation can be expected to extend survival.

Medications include cisplatin, carboplatin, and doxorubicin. Single drugs may be used alone, or multiple drugs may be combined.

If side effects such as loss of appetite, digestive symptoms, or bone marrow suppression (low white blood cell count) occur, symptomatic treatment may also be administered.

3. Radiation Therapy

Radiation is used to reduce cancer cells.

Radiation is used to treat tumors in areas where surgery is difficult or to relieve pain.

4. Palliative Care

Osteosarcoma is a painful disease, so painkillers are used extensively.

In addition to anti-inflammatory medications, stronger narcotic painkillers (such as fentanyl tape) may also be used.

Please follow your veterinarian's instructions carefully when using these medications.

5. Alternative and Complementary Medicine

Photothermography and supplements may be helpful in improving quality of life.

Treatment and Care at Home

Medications that can be administered at home include painkillers and medications to alleviate the side effects of chemotherapy.

Exercise may be difficult after amputation, so encourage communication using treats to help relieve stress.

Preventing Osteosarcoma

Since the cause of this disease is unclear, it is difficult to prevent.

However, early detection and treatment can alleviate pain and extend survival.

Have your dog undergo regular checkups and observe how it walks on a daily basis.

In addition, regular massage can help detect sudden pain and other symptoms early.

Also, be careful of injuries.

There's a theory that osteosarcoma can develop as a result of bone fractures, so try to create a safe space for your pet to avoid injury as much as possible.

If your pet exhibits symptoms such as a lump, abnormal gait, pain when touched, or prolonged pain from an injury, we recommend consulting a veterinarian as soon as possible.

Summary

Osteosarcoma is a very serious disease in dogs.

Even with treatment after diagnosis, it is said that only about 10% of cases survive for more than a year.

If your dog is diagnosed with osteosarcoma, you must decide what is best for you and your dog.

It may be painful, but should you continue with treatment as much as possible or choose euthanasia? It's a very difficult decision.

To prevent this from happening, early detection is important.

It's important to be mindful of your dog's behavior and to be aware of any changes by carefully observing it and giving it a massage.