Caring for a dog with cancer


Cancer - it’s a word that strikes fear into the heart of everyone, but it doesn’t automatically mean a death sentence.

Tumours, or growths, can be benign (non-cancerous) or cancerous depending on how they affect the body. Tumours that disrupt the body’s normal processes, or spread, are known as malignant and are cancerous, whereas benign tumours stay in the body tissue where they started and don’t cause harm.

The most common forms of cancer in dogs are mammary (breast) tumours, skin cancers (melanoma), lymphoma (cancer cells in the lymph nodes), and cancers of the digestive system.

What causes cancer in dogs?

Some breeds are thought to be more predisposed to some cancers than others, for example larger breeds such as Rottweilers, Great Danes, Bernese Mountain Dogs, and German Shepherds are thought to be prone to cancer, especially in their later years. Female dogs can also be prone to mammary tumours, which is why it is recommended that females are spayed before the age of two.

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Symptoms of cancer in dogs

The most obvious symptom of cancer is a lump on any part of your dog’s body, but, don’t panic, a lump doesn’t automatically mean cancer. Other symptoms of cancer affecting internal organs can include lethargy, weight loss, lack of appetite, difficulty breathing, and digestive problems. As most of these symptoms can be found in other illnesses, take your dog for a vet check.

Diagnosing cancer in dogs

Your vet will need to perform a biopsy of any lump, where a small sample of the growth is taken and examined under a microscope, to determine if it is cancerous, and then an ultrasound or MRI scan to see if the tumour has spread to other areas of the body. Your vet will then be able to determine what stage the cancer is at, and the best course of action.

Treating a dog with cancer

The best treatment will depend on many factors, including how advanced your dog’s cancer is, the type or tumour, his age, and general health. The most common treatments are surgery, chemotherapy, and radiotherapy. Many lumps that occur in the skin are benign and can be removed during surgery. In breast cancers, it may be possible to remove just the lump alone, or removal of some, or all, of the rest of the breast tissue may be necessary. Spaying a bitch at, or after, breast surgery could also reduce the chance of recurrence. If your dog has cancer of the bone (osteosarcoma), limb amputation may be necessary, but your vet will discuss all options with you.

Veterinary chemotherapy usually has few side effects, or none at all, because the doses used are smaller than those used in humans, and can be used for several types of cancer. Unfortunately, it does not usually cure the cancer — the aim is to slow the cancer down and reduce the symptoms.

Chemotherapy is sometimes carried out following surgery, or used in widespread cancers that cannot be surgically removed, such as leukaemia. Radiotherapy is a less common treatment, and relatively few vet specialists offer this treatment, and, like chemotherapy, it does not cure, but slows the cancer down.

How long can a dog live with cancer?

Obviously, your dog’s well-being and quality of life are of utmost importance, and many dogs with tumours are able to live a normal life for certain amounts of time. If it becomes clear that a dog is in pain and no longer enjoying his life, it may be kinder to end his suffering.


It is estimated that nearly 50 per cent of pets over the age of 10 will develop some type of cancer. In dogs, the increasing incidence of cancer is believed to be due to longer life spans.