You may have found lumps or growths in your dog's skin, or X-rays or ultrasounds may have revealed abnormalities and you're wondering: Does my dog have cancer? If so, what does that mean for my pet? And what exactly is cancer?
Cancer is the uncontrolled cell division, which leads to a displacement and destruction of surrounding tissue. Normally, cells stop dividing when they come into contact with surrounding tissue. If the cell continues to divide anyway, it is recognized by the immune system as a degenerate and eliminated. If neither takes place, this leads to uncontrolled growth.
There are many different types of cancer in dogs. Here, the word "tumor" is often used as a synonym. However, tumor means only swelling in Latin and says per se first of all nothing about the quality of the circumferential growth. That is, a tumor can be benign (benign) or malignant (malignant).
A final classification can only be made by examination in the laboratory. However, slow-growing tumors that can be easily differentiated are often benign. Fast-growing tumors with poor demarcation to surrounding tissue, on the other hand, is usually a bad sign. However, there are exceptions in both cases.
All types of cancer have one thing in common: if it is detected early and has not yet metastasized to other organs, complete removal of the primary tumor can lead to cure.
If complete removal of the (malignant) tumor is possible, the decision to operate should not wait long in order to minimize the risk of metastases, i.e. the spread of the tumor.
However, if metastases are already present, they usually lead to problems that are difficult to control. Cancers, as mentioned earlier, are a combination of degenerate cells and non-recognition by the immune system, and are therefore usually not contagious.
However, there are a few exceptions: Sticker sarcoma presents as a flesh-colored growth, particularly of the external genital organs. It is a transmissible type of tumor, which can be transmitted primarily, but not exclusively, during mating via small mucosal lesions. Fortunately, sticker sarcoma usually responds well to chemotherapeutic agents. However, most other tumors are not transmissible.
Below, I will discuss some more common tumors. However, there are a variety of other tumors both malignant and benign in nature. If you should observe circumferential growths in your dog, it is always advisable to consult a veterinarian.
But please remember that there can be many other causes for changes in the skin, for example, which are also accompanied by an increase in circumference, for example, cysts or abscesses. So please do not go crazy if you discover a lump on your pet, but have it examined by your veterinarian.
Visible tumors in dogs (cancer)
Circumferential growths of the skin can be lipomas, for example. These are benign growths of fatty tissue cells. They are usually clearly circumscribed, spongy to the touch, and are not a cause for concern.
In contrast, the malignant form, liposarcoma, is poorly circumscribed and has variable consistency. It is considered impossible for liposarcoma to arise from lipoma, and fortunately liposarcoma is rare.
Mast cell tumor in dogs
Mast cell tumors can be particularly treacherous because they can get smaller and lull the owner into a false sense of security. However, even among mast cell tumors, there can be very aggressive courses where waiting can be fatal. In addition, mast cell tumors can release certain substances that affect the entire organism and in the worst case can even become life-threatening.
Therefore, my recommendation is to have any circumferential proliferation of the skin examined by a veterinarian, especially if your dog belongs to a breed that is prone to mast cell tumors (for example, the Boxer). In many cases, surgical removal followed in part by chemotherapy is crowned with good success.
Breast cancer, mammary tumor, and mammary carcinoma in dogs
Circumferential growths of the mammary gland can be benign or malignant in nature. The treacherous thing about canine mammary cancer is that benign and malignant can be present in the same circumferential proliferation, and fine needle aspiration (that is, removal of a small amount of tissue using a syringe and cannula) can lead to false results.
A complete and generous removal of the tumor and usually the entire mammary gland is the treatment of choice, so it is recommended to examine the tumor in its entirety to further assess the prognosis. Mammary carcinomas readily metastasize to the lungs or ulcerate, which means they rupture and cause non-healing sores and pain to the dog.
An x-ray of the lungs and an ultrasound of the abdominal cavity is advisable to detect possible metastases. Early spaying of the bitch can massively reduce the risk of cancer of the mammary gland.
However, it should be noted that even spaying is not completely without risk, cancer development cannot be 100% prevented even by early spaying, and very early spaying itself can lead to further problems.
Squamous cell carcinoma
Squamous cell carcinomas often manifest as crusty, open or even weeping, usually painful changes and should be removed surgically over a large area. Because they have little tendency to spread, surgical removal often results in cure.
Squamous cell carcinomas can occur in many parts of the body, for example, on the tongue, toes, or especially on unpigmented areas of skin. But internal organs, such as the lungs, can also be affected.
In contrast to squamous cell carcinoma, so-called epulides are benign growths of the mucous membranes of the mouth and do not pose a problem in themselves. However, bacteria feel very comfortable in the pockets formed between the epulid and the gum or tooth and can lead to inflammation and pain. Epulides should be removed when they reach a certain size.
Cancer of the internal organs in dogs
Tumors of the internal organs are often detected late or, if one is lucky, diagnosed early as an incidental finding in other diseases. Unfortunately, the blood count often only gives indications of a tumorous event.
Cancers of the internal organs or the brain usually have the problem that the tumor itself does not cause pain or problems, but only when it presses on neighboring tissues or restricts the function of the diseased organ. Usually the cancer is then already quite advanced and the therapy is quite complex.
Brain tumor in dogs
Mostly it is rather secondary whether the brain tumor is benign or malignant, because only the space-occupying event is problematic. Brain tumors can lead to behavioral changes or epileptic seizures.
If pressure is put on the meninges by the tumor, it can also cause headaches, which could manifest as your dog pushing his head against walls, for example.
Brain tumors can often only be detected by CT or MRI and removal is often very difficult or not possible at all. Often the only thing that can be attempted is to improve the quality of life by controlling the pain or seizures.
Spleen tumor in dogs
Both benign and malignant splenic tumors harbor the risk of rupture, meaning rupture of the tissue. The spleen is very well supplied with blood and is surrounded by a capsule. If the tumor ruptures, there is a lot of bleeding, which may still be limited by the capsule.
In most cases, however, the capsule also ruptures and the dog can bleed to death within a short time. Thus, in the case of a splenic tumor, removal of the spleen should be done promptly. Especially considering that dogs tolerate life without a spleen very well.
An x-ray should be taken and the tumor should be examined in the laboratory for differentiation to determine the prognosis for continued survival. Spleen tumors unfortunately like to metastasize to the lungs and can then cause massive problems there. Hemangiosarcomas in dogs are particularly aggressive and metastasize early. They are especially found in the heart and spleen.
Lymphoma
Lymphoma can be detected quite well during a routine examination because of the usually generally swollen lymph nodes. A regular palpation of the lymph nodes, for example the jaw, bow or knee lymph nodes, can also be done by you and thus changes can be quickly detected and acted upon.
However, not every swollen lymph node is a lymphoma. In the case of an infection, some or, depending on the severity of the infection, all lymph nodes swell as well, because the immune system is working harder.
Only when certain cells of the immune system degenerate do we speak of a lymphoma. Tissues other than the lymph nodes can also be affected, such as the lungs, intestines or skin.
There are different types of lymphoma, depending on the cell line (T-cells or B-cells) from which they originate and, based on this, different degrees of severity. However, many lymphomas respond well to chemotherapeutic agents and the quality of life can be improved massively and often for a long time.
Stomach and intestine
Stomach ulcers, despite their name "ulcer" as in cancerous ulcer, are usually not a cancer in the sense of this article, but a defect in the stomach lining.
Often these gastric ulcers, also called gastric ulcers, are caused by hyperacidity due to stress or incompatible food. However, they can also do a lot of damage if left untreated, and the symptoms can closely resemble a true cancer.
True gastric tumors are usually malignant but fortunately rare. An endoscopic examination in case of food refusal, vomiting or other abnormalities in eating may be advisable to detect changes in the stomach wall.
Depending on the type of tumor, surgery or chemotherapy or a combination is the treatment of choice. The same is true for tumors of the intestine. Unlike the stomach, however, the intestine cannot be so easily examined endoscopically.
Here, mostly indirect procedures, such as ultrasound examination also in combination with an X-ray examination, CT or MRI, or direct procedures, such as diagnostic laparotomy/scopy are used for diagnosis. Laparotomy is the surgical opening and examination of the abdominal cavity. Laparoscopy uses minimally invasive surgery for this purpose.
Lung cancer in dogs
Primary or secondary tumors (metastases) can occur in the lungs, just like anywhere else. Accordingly, the type of tumor can be very variable. On x-ray, lung tumors appear as light areas in otherwise dark lung tissue; the veterinarian refers to this as "shadowing."
Since some cancers spread to the lungs, an X-ray examination of the lungs is always advisable in order to better assess the prospects for cure and survival and also the quality of life. In addition, this is the only way to decide whether surgery is even reasonable and possible.
The removal of lung tumors (whether as primary tumor or metastasis) is not easy and not every clinic is equipped for open chest surgery.
Bones
Cancer can also affect the bones. These tumors are highly painful and readily metastasize to the lungs, as well as other bones or organs. The affected bones often show swelling and can break spontaneously, without external force. Large breed dogs are particularly affected.
Treatment should be very early and aggressive. It often includes amputation of the affected limb followed by chemotherapy. However, radiation may also be attempted.
Survival despite tumor disease and conclusion about cancer in dogs
How long a dog with a tumor disease can survive is very different and depends on many factors: What type of tumor is it? There are very aggressive growing malignant tumors and slow non-infiltrative growing benign tumors.
As a result, survival time can range from a few weeks to several years. The location of the tumor is also an important consideration: does the tumor have room to grow (for example, in the skin) or can the surrounding tissue not escape (for example, the brain) or can the tissue itself rupture (for example, the spleen or heart)?
The more space the tumor would have and the less the surrounding tissue has been damaged, the easier the therapy is. Surgical removal is also more promising if much of the surrounding tissue can be removed so that all the degenerate cells can also be safely removed.
And of course the general condition of the dog has an influence on the survival time. The later the cancer is diagnosed or the more problems have already occurred, the more difficult the therapy will be.
The prognosis, i.e. the estimation of the chance of healing or the survival time, can be best made by your veterinarian when a sample or the whole tumor is examined in the laboratory after removal and all information (location, quality, extension) is known.
The diagnosis "cancer" does not mean that you have to say goodbye to your pet. A therapy is in many cases, however, associated with some costs, even quickly in the four-digit range, so that a pet health insurance is always worthwhile in this regard.
The last aid for the suffering dog
However, if the tumor disease is not only malignant, but a therapy does not improve the quality of life of your dog, you should not deny your faithful companion the last help. In the so-called final stage of cancer, there is nothing left medically to improve the quality of life and both the owner and the veterinarian are powerless.
Strong medication can sometimes still bring a few days of improvement, but in these cases euthanasia (active euthanasia) is unfortunately often the last service we can still render our pets, to spare them unnecessary long suffering.
I have often felt in such cases as if the animals were letting go in the presence of their beloved owner and as if they were gratefully accepting death. If your vet brings up euthanasia, please don't wait too long to make the decision. It is always difficult, but no one deserves to suffer and for our animals, we can at least make their final journey easier. Next, read our post about euthanizing dogs, which you can find here.