Bone cancer in dogs osteosarcoma and bone metastases

Bone cancer in dogsDiagnosis of bone cancer is a big shock, and not just for us bipeds! Our four-legged companions can get sick, too. Die unfortunately also from the consequences. Particularly large dogs and giant breeds such as Great Danes, German Shepherds and Co. Have an increased susceptibility (predisposition). But what is actually bone cancer? And is there perhaps even a therapy possibility to help the beloved pelt-nose?? We clarify the most important questions for you.

Primary and secondary tumor in dogs – what is it??

To address the specific bone tumors, we must first clarify the terms primary and secondary tumor. Primary tumor means the tumor that appears first. It results from the failure of various regulatory mechanisms during cell division. This is how the body's cells can spread unchecked. Depending on their origin, they can be sometimes more, sometimes less dangerous. Because they can grow aggressively. Destroy the healthy tie. Many primary tumors like to spread. This means that the altered tumor cells spread to the rest of the body. In this type of bone cancer, tumor cells often migrate (metastasize) into blood vessels and are thus washed onward. Eventually they end up in new organs. Form there so-called secondary tumors (metastases).

Bone cancer in dogs – what is meant by it?

Bone cancer (osteosarcoma) is a malignant tumor of the bone that can occur almost anywhere in the skeletal system of dogs, humans and mice. There are several types of tumors that are grouped under the term.

Primary bone cancer (chondro- and osteosarcoma)

They belong to the primary tumors. These are malignant growths that can spread throughout the body by metastasis and arise from bone (osteosarcoma) or lung (osteosarcoma). cartilage tie (chondrosarcoma) develop. The primary bone cancer is characterized by aggressive growth. Often the growth is accompanied by destruction of the surrounding bone or even the joint. Leads to disturbances in the movement of the dog. This type of tumor belongs to the group of sarcomas – malignant growths of soft ties that tend to spread (metastasize) via the bloodstream (hematogenous). The lung seems to be particularly susceptible to metastases from bone.

Bone metastases (secondary tumors)

Metastases are the settlements or. Malignant secondary tumors whose origin is in another organ. Prostate cancer (prostate carcinoma) or breast cancer (mammary carcinoma) have the ability to fight their way into the bones and then settle there. The bone and cartilage tie need not therefore be the place of origin of the tumor. By spreading (metastasis), tumor cells that originated in other organs can also migrate to the bone and grow there as secondary tumors. What are the causes. Consequences of bone cancer in dogs? Bone cancer can be particularly common in large dogs. Giant breeds are observed. Among others, there seems to be a genetic predisposition in Great Danes, Rottweilers, St. Bernards and German Shepherds. Specialists also suspect that osteosarcoma may also be due to trauma, such as bone fractures, etc., can be traced back to.

In the outbreak of osteosarcoma, important regulatory systems for the organism are upset by the release of messenger substances (cytokines). This mechanism of action is also called the paraneoplastic effect.

In the bone there are different cells that have different functions. On the one hand, there are the osteoblasts, they form new bone material. In addition, there are osteoclasts, which break down bone substance. Normally these two types of cells keep the balance and build up as much bone substance as is broken down. It is normal that remodeling processes take place in the bone. The balance is disturbed by the released cytokines, i.e. the messenger substances. Thus, either too much bone substance can be incorporated, resulting in bone growths that displace healthy tie. But the balance can also be on the degrading side. Then too much bone substance is broken down. Thus, the bone becomes very unstable. Can fracture even under light load (pathological fracture).

Symptoms: How to recognize bone cancer in dogs?

The signs (symptoms) of bone cancer are often not very obvious. They range from lameness to severe pain to fractures. The following symptoms occur with the different types of bone cancer:

Symptoms in chondro- and osteosarcoma

In this type of bone cancer, swelling occurs on the bone itself. Most often the bones in the limbs are affected. Especially swelling near joints can cause your dog to be restricted in his movement. In addition, bones can become unstable due to excessive breakdown of bone substance and break quickly, even with light weight bearing. Relief of the limb. Severe lameness are the consequences.

Symptoms of bone metastases

The main symptom of bone metastases is great pain. Moreover, the metastases can settle not only in the bones of the limbs, but also in the vertebrae of the spine. This can damage the spinal cord, causing paralysis. When bone metastases grow into healthy bone tie, they destroy it.

Untypical symptoms of bone cancer

As you know, the bone substance contains a lot of calcium. If the bone is destroyed, a lot of calcium is released into the body. In some cases there are even reports of excess calcium in the blood (hypercalcemia). When bone substance is broken down, calcium, which is stored in the bone, is also released. The free calcium, in turn, has important regulatory capabilities and can lead to headaches as well as muscle pain, muscle weakness, nausea and vomiting, and even cardiac arrhythmias.

At very high concentrations, hypercalcemic crisis may even occur. This is the name given to the condition when the body functions are extremely limited due to the excessive concentration of calcium in the blood. This can lead to loss of consciousness, coma or even cardiac arrest.

Diagnosis: "Osteosarcoma. How to confirm the suspicion?

The classic X-ray can provide information. Because a bone dissolution or bone proliferation can be recognized in the X-ray image.

Another imaging option is scintigraphy. This method is a special examination in which weak radioactive substances are administered to produce an image contrast. The radioactive substance accumulates in areas with a high blood supply, such as a bone metastasis. So the changes can be marked. Better localized.

If necessary, the imaging techniques mentioned above can be combined with computed tomography (CT).

A biopsy can confirm the suspected diagnosis of osteosarcoma at the cellular level (histologically). The type of cells in the tie sample can be used to determine whether they are tumor cells. In addition, a biopsy gives more detailed information about the tumor grade and the chances of therapy. Unfortunately, the removal is often very difficult and can be unpleasant and painful for the patient!

Therapy options for bone cancer

Nowadays, there are a number of effective treatments that not only relieve the symptoms, but also inhibit tumor growth.

Which type of treatment is suitable for your dog depends on many factors, but especially on the health and condition of the animal.

The most important types of treatment for dogs include surgery, radiation, chemotherapy and hormone therapy.

Surgical therapy – amputation of the affected limb

The safest way to get over the cancer is to remove it from the body. This prevents the tumor cells from spreading further.

Unfortunately, bone cancer mostly affects the limbs. If your dog is diseased, the vet may suggest amputation of the leg. This is a shock for most dog owners and absolutely understandable. However, if you find yourself in such a situation, you must keep in mind that a leg amputation has a slightly different meaning for your dog than it does for you. Most dogs learn very quickly after amputation to balance themselves on their remaining three legs. At the latest, when the previously terminally ill dog romps across the meadow like a wild animal after a few weeks of recovery, the fears and worries that one has with such a large operation have been worth it.

Of course, surgery itself is a major procedure and should be performed by a veterinarian who is well versed in such operations. However, a skilled small animal surgeon is a specialist in his field. Has also certainly performed such operations a few times.

Many pet owners are afraid of the so-called phantom pain. In fact, this is a problem that exists in the animal world as well. In the meantime, however, this topic is also quite well researched. Thus, there are findings on how proper pain management or other methods can help or even prevent phantom limb pain in dogs. As mentioned above, most dogs cope quite well with the redistribution of their weight to only three legs. However, you as the dog owner can help him to get used to the new form of movement by slowly training him or consulting a physiotherapist.

In the meantime, there are even prostheses for dogs that have problems balancing themselves on only three legs due to their anatomy or other diseases. This can be a real alternative.

Radiation therapy

Very effective is also radiotherapy (radiotherapy). The ionizing radiation or particle radiation becomes local. Targeted to destroy tumor cells. Especially in case of bone pain, a good result can be achieved in this way.


The approach of chemotherapy is based on treatment with chemical substances called chemotherapeutics or cytostatics. These drugs can intervene in the cycle of the cell and stop reproduction. However, they attack not only the enemy cancer cells, but also the body's own cells. The cells that divide quickly (mucous membrane, hair root…) are damaged first. So it can happen in the dog z. B. hair loss, digestive tract disorders, and inflammation of the mucous membranes of the mouth and nose. Vomiting and emaciation are very often seen side effects. Over a period of time your dog will be visibly unwell! But there is a chance for healing! However, this method of therapy should be thoroughly considered. To be discussed individually with the vet (veterinarian).

(Anti-)hormone therapy (endocrine therapy)

If your dog's bone cancer is a metastasis that has spread from another tumor (e.g., a tumor that has spread to another part of the body), the tumor will be removed. B breast cancer), it sometimes makes sense to treat the source of the evil first. There are various tumors that need hormones to grow. In this case, the dog can be given hormones that inhibit the growth of the primary tumor.

Often a combination of these therapeutic approaches is chosen. The main focus is on pain therapy.

In case of bone cancer in the final stage, however, the symptoms of the dog are usually so severe that therapy must be discouraged. In this case, redemption (euthanasia) is recommended. Bone cancer is often associated with a lot of pain for the dog. Unfortunately, still has a very unfavorable medical prognosis (prognosis). In therapy, good pain management is especially important to avoid subjecting your faithful companion to unnecessary suffering.

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