Cancer doesn’t only affect humans. Many animals also suffer from the deadly disease. Tasmanian devils can develop facial tumors, and Californian sea lions suffer from urogenital cancer. Beluga whales in Canada’s St Lawrence estuary are affected by intestinal cancer, which has been shown to be the second most common cause of death among these mammals. Cancer can also affect dogs and cats, which are the animals that humans are most familiar with. In fact, the mortality rate from cancer in animals is pretty much the same as in humans. In this article, you’ll learn about the signs of cancer in dogs and cats, and whether or not a cure is possible.

Dogs, Cats, & Cancer

Cancer is among the leading chronic diseases that affect middle-aged and older cats and dogs. In fact, around 33 percent of cats and around 50 percent of dogs over 10 years of age can be affected with cancer and can die from the disease. The signs of cancer in dogs and cats can vary depending on the kind of cancer they suffer from.

What Causes Cancer in Dogs and Cats?

Just like in humans, the causes of cancer in dogs and cats are diverse. The sources that cause various kinds of cancer in these animals can begin to make slight changes to the cells at an early age and can continue to pile on negative and adverse effects until cancer eventually develops as the dogs and cats age. Two of the most common precursors to cancer in these animals are a poor immune system and chronic inflammation. Explained below are some common causes of cancer in dogs and cats.

The Diet Pets Are On

Studies show that feeding pets food that has been heat-processed can cause chronic inflammation, which can eventually lead to cancer. Processing foods using heat reduces their nutritional value because the wholesome and high-quality ingredients present in these foods are chemically altered. Such a poor diet can also cause immune imbalances in dogs and cats.

Excess Vaccination of Pets

dog vaccination

While vaccination is necessary to encourage a preventive response from the pet’s immune system, unnecessary and frequent stimulation of the immune system can turn out to be harmful. To work around this, pet owners need to strike a delicate balance between the two and vaccinate pets for the necessary diseases alone.

Environment Factors

This is fast becoming one of the most common causes of cancers in dogs and cats. A variety of sources like the smoke from cigarettes and the general pollutants in the atmosphere can lead to the disease in these animals. Avoiding long-term exposure to environmental and chemical pollutants can help mitigate how they cause cancers in dogs and cats.

Types of Cancer in Dogs and Cats

Dogs and cats display various signs of cancer depending on the type of the disease they are affected. Some of the common cancers that affect dogs and cats are listed below.

  • Abdominal cancer
  • Bladder cancer
  • Osteosarcoma or bone cancer
  • Mammary gland cancer or breast cancer
  • Feline leukemia
  • Lymphoma or cancer of the white blood cells, lymph nodes, spleen, intestines, and bone marrow
  • Oral cancer
  • Prostate cancer
  • Testicular cancer

Is There a Cure?

dog face

Cancer isn’t just one disease. It is a group of diseases that can affect different groups of cells in varying ways. When it comes to cancer in dogs and cats, many pet owners believe that treating the disease isn’t very useful and that it is only a manner of delaying the inevitable. However, the truth is that just like cancer in humans, cancer in these animals can be treated, and in some cases, even cured. If the tumor is aggressive, or if the cancer is fast-growing or has been detected in its later stages, it can be a challenge to treat the disease. However, in other cases, treatment can shrink tumors, control the growth of cancer cells, and can eventually result in a cure.

Dogs & Cats – 10 Signs of Cancer

boys watching the dog

The signs of cancer in dogs and cats aren’t easily noticeable as symptoms of the deadly disease. This is primarily because the signs of cancer often mimic the symptoms of other common illnesses. However, being aware of the symptoms and signs of cancer can help pet owners get their dogs or cats checked up earlier, thus saving valuable time and allowing them to begin treatment on time, if necessary. In this vein, here are some of the signs of cancer in dogs and cats to look out for.

Lethargy and Depression

This isn’t among the easily noticeable signs of cancer, but if you observe your dog or cat for a few days at a stretch and find that they’re more tired and less active than usual, you may want to get them checked. Fighting cancer can consume a lot of energy within the body, leaving your pet feeling lethargic and even depressed.

Unusual Odors

sick dog

This is another one of the many signs of cancer that resemble symptoms of other relatively less dangerous illnesses or conditions. Nevertheless, if you notice any foul odors from your pet’s mouth, nose, ears, or near the anal region, keep a check on it to see if it is persistent. If it doesn’t subside eventually, a visit to the vet may be the best thing to do.

Symptoms of Pain

Some cancers like cancer of the bone can result in pain in dogs and cats. Check for sensitivity in any particular area of the body, and notice if your pet shows signs of pain like limping or reacting violently when you touch any specific part of their body. Unexplained aches can be caused by bone cancer or by tumors that press into the nerves, causing pain.

Abnormal Discharges

Among the other, easily noticeable signs of cancer in dogs and cats are abnormal discharges from their bodies. Discharges from the skin like blood and pus or discharges from the insides of the body like vomit or diarrhea can all be signs of cancer. While there may be other causes that could lead to such discharges, persistent blood, and pus discharge could be cancer.

Unexplained Weight Loss

Weight loss, which is among the common signs of cancer in humans, is also a symptom of the disease in dogs and cats. If your dog or cat seems to be losing weight, and if there’s no unusual or sudden change you’ve made in their diet, it may be necessary to have a vet check the animal. Weight loss, especially when accompanied by any of the other signs, can be cancer.

Changes in Bathroom Habits

If your pets display sudden and usual changes in their bathroom habits that are persistent and last for a significant period, it could be one of the many signs of cancer. Changes can include more frequent urination, passing stools more regularly, difficulty in urination or passing stools, and blood in the excreta. All of these could be signs of cancer to watch out for.

Appetite Changes

Occasional and minor changes in appetite are common in dogs and cats, and may not indicate signs of cancer. However, a progressive decrease in the interest to eat regular meals can be an indication of trouble. An increase in thirst could also be among the signs of cancer. While these symptoms may not always mean cancer, it would be wiser to have them checked out.

Sores That Don’t Heal

It’s quite normal for dogs and cats to suffer from sores or wounds because they could bump into things. However, these wounds generally heal in a few days or weeks. When these animals suffer from cancer, their immune systems may be compromised, thus slowing down the healing process. So, it’s best to get it checked out if your pet has any non-healing sores.

Breathing Difficulties

Coughing or difficulties in breathing can also stem from conditions like heart disease or lung infections. However, another possible cause of such breathing troubles could also be cancer. It can be a result of cancer in the lungs, or as a result of cancer in another part of the body that has metastasized to the lungs.

Suspicious Lumps and Bumps

Lumps and bumps may be common in dogs and cats. But if you notice that the lump is growing or if it doesn’t seem to resolve itself soon, it’s best to take your pet to the vet. A biopsy is the best way to determine if a lump or bump is benign, or if it is potentially cancerous. Finding out early on what the prognosis is can help you seek treatment for your dog or cat.


It’s necessary to remember that while these are the common signs of cancer in dogs and cats, your pet may display an entirely different set of symptoms. The bottom line is to look out for anything unusual and to keep a track of it to determine if it seems persistent. If you notice any abnormal changes, it’s best to take the dog or cat to the vet and get it checked out.