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Cancer in Dogs

Josie F. Turner
By Josie F. Turner, Journalist specialized in Animal Welfare. Updated: October 10, 2018
Cancer in Dogs

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Much like humans and other animals, dogs are susceptible to suffering from cancer. Cancer is a group of diseases caused by the uncontrolled proliferation of cells. This uncontrolled cell growth causes an excess of tissue, known as a tumor or growth.

Malignant tumors can disperse the diseased cells to other parts of the body, which makes them extremely dangerous. These are the so-called cancerous tumors. Benign tumors, on the other hand, are not cancerous as they do not spread to other parts of the body. However, it might be necessary to surgically remove them when they hinder normal body functions.

This AnimalWised article will detail all you need to know about cancer in dogs: the different types that exist and the symptoms, diagnosis and treatment.

You may also be interested in: Breast Cancer in Dogs - Symptoms and Treatment


  1. What is cancer?
  2. Symptoms of cancer in dogs
  3. Diagnosis of cancer in dogs
  4. Treatment of cancer in dogs
  5. How to prevent cancer in dogs

What is cancer?

This disease begins on a cellular level, when a genetic error is produced in the transcription. A cell that should perform a particular function stops doing so and starts to multiply uncontrollably, creating excessive tissue.

There are hundreds of different types of cancer that can affect your best friend, and they are all manifested differently. Tumors are divided into two types: -oma (which are benign) and carcinoma or sarcoma (which are malignant). The main difference is that a benign tumor reproduces excessively without affecting other organs, whilst malignant tumors can affect the entire body.

What are the most common types of cancer in dogs?

  • Skin cancer
  • Breast cancer
  • Cancerous tumors on the head and neck
  • Lymphoma
  • Testicular cancer
  • Bone cancer

There is no specific theory behind the causes of cancer in dogs. However, there are factors that can aggravate the condition such as inbreeding, exposure to toxic chemicals or extreme solar radiation.

There is also a predisposition in older dogs, dogs which suffer from poor living conditions and those which have serious illnesses that are left untreated. A high quality diet, excellent care and attention and proper sanitation somewhat reduce the development of this disease.

Rarer types of cancer in dogs also exist, but they are generally region dependent. For example in areas with lots of stray dogs lack of vaccination and sterilization can increase the likelihood of certain cancers. Only one of thee cancers is communicable from one dog to another. This is known as a canine transmisible venereal tumor (TVT). It will not always metastasize, but does respond well to treatment when diagnosed in time.

Which breeds have a greatest predisposition for cancer?

  • Boxer
  • Golden retriever
  • Labrador retriever
  • Bulldogs
  • Mastiffs
  • Saint Bernard
  • Bulldog
Cancer in Dogs - What is cancer?

Symptoms of cancer in dogs

Cancer usually goes undetected until it reaches a considerable volume. It is then when the majority of owners are alerted by its abnormal condition, either as a result of behavioral changes or visible tumors.

Sticking tightly to the dog vaccination schedule and going to the vet every 6 months are excellent ways to detect a possible cancer as soon as possible. Older dogs and puppies should go to the to specialist at closer intervals, every four months.

Here are some of the symptoms associated with the onset of cancer:

  • Pain
  • Discomfort
  • Vomiting
  • Crying
  • Abnormal swelling
  • Abnormal growths
  • Ulcers which do not heal
  • Loss of appetite
  • Weight loss
  • Regular bleeding
  • Rotting smell in certain areas
  • Lack of enthusiasm
  • Apathy
  • Behavioral change
  • Stiffness in a particular area of the body
  • Difficulty swallowing
  • Difficulty breathing
  • Difficulty urinating
  • Difficulty defecating
  • Difficulty in doing exercise
Cancer in Dogs - Symptoms of cancer in dogs

Diagnosis of cancer in dogs

Cancer is common in dogs, being especially frequent in dogs over 10 years old. However, diagnosis is not always easy because the symptoms in the early stages of the disease may go unnoticed.

Blood tests, X-rays, routine veterinary examinations and ultrasounds can give circumstantial evidence of cancer. However, a reliable diagnosis usually requires a biopsy.

Biopsies consist of a small extraction of the animal's tissue that might be cancerous, which is subjected to analysis. The vet is the only professional who can provide you with an accurate diagnosis of this disease, clarifying whether it is a benign or malignant tumor.

Cancer in Dogs - Diagnosis of cancer in dogs

Treatment of cancer in dogs

The treatment of cancer in dogs should be recommended and monitored by a vet. This treatment may include surgery, chemotherapy, radiotherapy and immunotherapy. Given that these treatments are often specific and complicated, it may be necessary to secure the participation of a vet who is specialized in oncology. The course of treatment will depend on the type of cancer that your pet is suffering from, and where it is on the body.

The consequences of cancer in dogs may vary. In some cases, dogs may not experience any physical illness at all, but in others the animal may be in pain and discomfort. In these cases, it is highly recommended to use drugs or homeopathy products designed for dogs with cancer to try and reduce the dog's pain.

Cancer in Dogs - Treatment of cancer in dogs

How to prevent cancer in dogs

It is very difficult to prevent cancer since its causes are usually unknown. However, looking after your dog well and getting going for regular check ups at the vet will help to keep your dog in a general state of good health.

Early detection of cancer is essential in order to treat the disease as soon as possible, preventing it from spreading throughout the body.

Cancer in Dogs - How to prevent cancer in dogs

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to Cancer in Dogs, we recommend you visit our Other health problems category.

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Cancer in Dogs