If the veterinarian makes a diagnosis of cancer, it is usually a huge shock for the dog owner. Cancer is still the leading cause of death in dogs. But diagnosed early enough, new therapies can significantly extend a dog’s life and improve well-being.
Risk factors for cancer in dogs include:
It is often not just a single cause that leads to the development of cancer, but a combination of various factors.
Rottweilers are prone to cancer. © Stock.adobe.com/Grigorita Ko
Most cancers affect the skin, but in principle any cell in the body can degenerate into cancer cells. In cancer, the genetic makeup of the cells has changed. As a result of this mutation, the cancer cells no longer fulfill their original tasks and multiply in an uncontrolled manner. In these cases a lump develops.
Early detection increases the chances: Solid skin tumors can be detected early if the dog’s entire body surface is regularly scanned. Any nodules, sores, or other changes seen during this examination should be checked for over the following days and weeks. If the changed areas of skin do not heal after a few days or weeks, they should be shown to a veterinarian.
Dog owners should always take the following abnormalities seriously, as they can be signs of cancer in the dog:
Reluctance to move can be a warning sign. © Stock.adobe.com/chalabala
Benign tumors tend to grow slowly. They usually form a solid capsule that separates the degenerated cells from the healthy tissue. Due to this separation of healthy and diseased tissue, a benign tumor can usually – unfortunately not always – be surgically removed. With benign tumors there are no daughter tumors (metastases). Benign tumors can also cause major problems in individual cases if, for example, their growth restricts the dog’s mobility or constricts vital organs.
Malignant tumors often grow into healthy tissue with delicate extensions. The tiny extensions of the tumor tissue cannot be distinguished from healthy ones with the naked eye. Therefore, there is a great risk that the surgeon will not remove all of the cancerous tissue and relapse. Daughter tumors (metastases) represent a major problem with malignant tumors because they can spread the cancer throughout the entire organism.
Dogs are particularly often affected by these types of tumors:
Skin tumors are particularly noticeable. © Stock.adobe.com/cynoclub
Cancer therapy has made great strides in the last few decades. In the case of incurable tumor diseases, treatments are used that curb cancer growth and alleviate the patient’s pain and other symptoms, so that the animal regains zest for life.
In fact, the focus in veterinary medicine is not on extending the dog’s life, but on the patient’s quality of life: a dog with cancer should be able to enjoy life largely painlessly and in the manner of the dog. In many cases the various therapies have to be combined with one another.
The removal of the cancerous tumor is the most important form of treatment for many types of tumors. If the tumor can be completely removed and no daughter tumors (metastases) have formed, the patient is cured. Unfortunately, an operation is not always possible (e.g. blood cancer, metastases).
However, some types of cancer cannot be operated on because an operation would be too dangerous (e.g. brain tumors, very large tumors), or because important parts of the body (e.g. nose) would have to be removed.
In veterinary medicine, chemotherapy has fewer and milder side effects than humans. Chemotherapy is very often used in dogs with cancer to improve their quality of life. Minor side effects such as mild nausea can be managed with other medication.
The development of more compatible chemotherapeutic agents remains an important goal of cancer research. Another current approach in cancer research is the development of vaccines against certain types of cancer. In the USA, a vaccine against a specific cancer of the oral mucosa (canine oral melanoma) is already in use to support conventional therapy.
High-energy rays such as gamma rays or X-rays damage the genetic material of the tumor cells, prevent them from multiplying and, in the best case, kill the cancer cells. Unfortunately, radiation makes no difference between tumor cells and healthy cells. In order to protect healthy cells from radiation, more targeted devices and more precise shielding mechanisms have been developed in recent years. In addition, it has been recognized that the healthy cells are spared if the radiation dose is fractionated, i.e. divided over several sessions.
Another method that is supposed to protect healthy tissue is brachytherapy. Radioactive particles are usually enclosed in metal rods and implanted in the tumor. The advantage of this method is that the tumor cells are irradiated directly, while the healthy tissue hardly receives any radiation. However, brachytherapy is not possible for all tumors.
Accompanying measures play an important role for the well-being of the dog. The diet must be tailored to the dog’s needs, but above all it must also taste good, because the dog should stay strong. Gastric protection therapy can sometimes help dogs who experience nausea. Effective pain relief is a must in painful processes and often promotes recovery after an operation.
Physiotherapeutic measures should be carried out by an expert. The animal physiotherapist should also show you simple massage techniques or exercises that you can do at home without causing damage.
Chemotherapy is also possible in dogs. © Stock.adobe.com/antoine-photographe
Despite all the improvements in recent years, not every cancer is curable. And modern cancer therapy is not possible or useful for every dog. In all animal cancer patients, the benefit of the therapy must be carefully weighed against the stress it brings on the animal.
But the burden for the pet owner must not be disregarded either. Some cancer therapies can cost several thousand euros – not everyone can afford that. Others require a lot of time, for example if the nearest radiation clinic for dogs is a long way away.
Even if you decide against cancer therapy: The most important thing is the animal’s well-being. Often you can maintain your quality of life for some time with pain medication – but if the animal begins to suffer, you have to face your responsibility and let the veterinarian relieve it of its suffering.