Cancer in Pets – Q&A

1 November 2023

It’s estimated that one in four dogs and one in five cats will be diagnosed with cancer in their lifetime.

As November is Pet Cancer Awareness Month, we spoke to Jane Dobson, Ryan Soussa, Tam Kearns and Petros Odatzoglou in the Oncology Team at the Queen’s Veterinary School Hospital, University of Cambridge, and asked them some of the common questions pet owners may have about cancer in pets.

• Can all animals get cancer?

All species get cancer – mammals, birds, reptiles, fish. Whales and elephants have lower cancer incidence despite the vast number of cells composing their body. The naked mole rat doesn’t get cancer.

• What types of cancer can pets get?

There are hundreds of types of different cancers identified in pets, including brain, heart, lung, liver cancer among others. Some of the most common tumours in dogs affect the skin, for example mast cell tumours, and in cats, lymphoma is a particularly common type of cancer.

• Are some breeds more prone to developing cancer than others?

Certain breeds of dogs have a predisposition for certain types of cancer. For example, pugs and boxers tend to develop mast cell tumours and Flat Coated Retrievers and Bernese Mountain Dogs commonly present with histiocytic sarcoma. Giant breed dogs such as Wolfhounds, Great Danes, and Saint Bernard’s are prone to develop bone cancer. Whilst cancer is typically a disease of older animals, it can affect pets of any age.

• What causes cancer in pets?

The breed predispositions outlined above suggest a genetic component for some tumours. Trauma and inflammation may be implicated in some circumstances, for example in feline injection site sarcomas. Some cancers are caused by a virus, such as papillomas in cattle and sarcoids in horses. Lastly, some cancers have environmental causes such as sunlight exposure and squamous cell carcinoma (a form of skin cancer) in cats.

• What are the signs of cancer I should look out for in my pet?

Cancer can manifest in many ways. It may present as an obvious mass in or under the skin. Some tumours on the limbs may present with lameness while deeper seated tumours in the abdomen or chest might show generic clinical signs such as weight loss, lethargy, weakness, and inappetence. Tumours in the brain may present with neurological signs such as seizures. Any ongoing, progressing and unexplained signs such as bleeding, coughing, vomiting or diarrhoea should be investigated sooner rather than later.

In most cases, cancer cannot be detected in routine blood samples with the exception to this being some types of blood cancer (e.g. leukaemia). There is ongoing research though to identify biomarkers that will aid early diagnosis of cancer in pets.

• What are the treatment options for cancer in pets?

Treatment options vary depending on the type of cancer a pet has. Surgery is usually the mainstay for most common tumours but other options include chemotherapy (treatment of choice for lymphoma) or radiotherapy, which may be used alone or in combination. Many cases benefit from a multimodal treatment approach. In the most recent years, other options such as immunotherapy and targeted treatments have also arisen.

• What is the long-term outlook for a pet with cancer?

Many commonly presenting tumours in dogs and cats can be managed successfully by surgery alone or in combination with other treatment options. These include low grade mast cell tumours and soft tissue sarcomas in dogs. Superficial squamous cell carcinomas is an example of frequently cured cancer in cats. Even in circumstances where cancer cannot be cured, long-term remission and good quality of life can be achieved with treatment. In many cases, cancer is now treated as a chronic disease.

• Can cancer spread from one pet to another or to me?

Generally no, cancer does not spread from one pet to another or from a pet to its carer. There are two notable exceptions to this rule. There is transmissible venereal tumour which affects dogs in various parts of the world and is transmitted via close contact. It is rarely reported in the UK except for dogs being rescued from Eastern Europe.