Cancer Statistics In Pets

Picture of a dog and cat on a sofa

According to some recent data, approximately 25% of all dogs across the world will develop one form of cancer during their lives. The statistic is even higher for dogs that are over the age of 10, with 50% of this category developing cancer until the end of their lives.

To find out more about how cancer has affected cats and dogs in recent years and why these numbers are important for both human and animal patients, read the article below.

What Types of Cancer Are More Common in Cats and Dogs?

Some studies suggest that lymphoma is one of the most common types of neoplasia that affect pets, but the truth is that it tends to affect cats more than it does dogs.

Skin cell cancer

Skin cell cancer cases are statistically more common than other forms, with mast cell tumors being at the top of the list. Approximately one third of all cancer cases in dogs are skin tumors, and 20% of these are mast cell tumors.

50% of skin tumors can be found on the pet’s body, in general, while approximately 40% of them are located on the limbs (especially the hind ones), the neck, or the head. 11% of skin tumors show up in several different body regions at the same time.

Cats are less exposed to skin cell cancer, although they can develop mast cell tumors just like dogs do. Unfortunately, most skin cancer tumors are malignant.

Mammary gland cancer

Approximately half of all breast (mammary gland) tumors in dogs are malignant, but what’s absolutely baffling is the statistics in cats. It seems that over 80% of all mammary cancer cases in cats are malignant.

Spaying your canine or feline companion before they get to the age of 12 months can significantly reduce their chances of developing this type of cancer – not to mention that the procedure also reduces the chances of your pet of ever suffering from cancer of the reproductive system (ovaries and uterus).

Head and neck cancer

Mouth and nose cancer are particularly common in cats. This type of cancer is usually associated with symptoms such as lack of appetite, local pain, and sometimes bleeding from the mouth or the nose. Some animals might have facial swelling or they could experience difficult breathing, depending on how much the cancer has spread.

About 45 cats in 100,000 end up suffering from oral malignancies, out of which 69% are squamous cell carcinomas and 18% are represented by fibrosarcomas.

6% of canine cancers are oral tumors, but even with this somewhat low percentage, mouth cancer is still the fourth most common cancer that male dogs are likely to develop.

Testicle cancer

Although testicular cancer is one of the rarest forms that both cats and dogs can develop, it can still affect some animals. In most cases, it appears in pets that have retained testicles (whether they are located in the abdomen or between the latter and the scrotum).

27% of all unneutered male dogs have a chance of developing testicular cancer in one or both of their testes. In general, testicular cancer makes up anything between 4 and 7% of all cancer cases in dogs.

Testicular cancer cases are extremely rare in cats and only a few cases are reported on occasion — a reason for which a statistic is practically impossible to calculate.

Bone cancer

Bone tumors are more common in large and giant dog breeds, especially those that are older than the age of 7. They are somewhat rare in cats. Bone cancer can show up in any body area from the leg bones to the ribs.

Malignant bone cancer in cats is anything but common, but it still has an incidence of about 5 cases per 100,000 individuals. Out of all the bone tumors that cats can develop, osteosarcoma accounts for seventy percent of them.

Although about 10,000 dogs are diagnosed with bone cancer every year, 80% of all cases are osteosarcomas.

Abdominal tumors

When it comes to abdominal tumors, there is a wide variety of cancer types and organs that can be affected. Some can be benign, others can be malignant, and some forms can be painful and lethal.

It’s practically impossible to give a fixed number or a fixed incidence about abdominal cancer, both in cats and in dogs, as the masses that are discovered during routine check-ups can often be anything from a hemangiosarcoma (a common spleen tumor) to a carcinoma (a common liver tumor).

In some cases, carcinomas of the mammary gland can spread to abdominal organs, especially if the lower mammary glands are affected. By contrast, if the neoplasm is initially located in an upper mammary gland, it has a higher chance of spreading to the lungs – this applies for both species.


Consisting of the enlargement of one or several different lymph nodes across the animal’s body, lymphoma is another common type of cancer that affects both cats and dogs. It’s more common in cats since it can be caused by the Feline Leukemia Virus.

Lymphoma accounts for approximately 33% of all tumors in our feline friends, and its incidence is 40 to 200 cases in 100,000 cats. This disease affects cats with ages ranging from 4-5 months to 19-20 years.

By contrast, just 7 to 24% of all cancer cases in dogs are lymphomas. Dogs develop a form that’s comparable to what humans experience (non-Hodgkin lymphoma).

What Is the General Incidence of Cancer in Cats and Dogs?

This is another question that’s not exactly easy to answer. Several studies are performed once every couple of years, and the data depends on the area the dogs or cats are located and the potential carcinogenic substances they might be exposed to.

According to a study from 1978, the incidence of cancer at that time was 507 per 100,000 in dogs and 412 per 100,000 in cats. But a study from 2000 showed that the incidence was 852 per 100,000 in dogs and 319 per 100,000 in cats.

People like to say that pets now develop cancer a lot more frequently than they used to back in the day and while that might be true in some respects (such as the less widespread use of carcinogenic substances in food or even the lack of commercial food in the first half of the 20th century, which made pet parents prepare the food themselves), the truth is that both dogs’ and cats’ life span has increased a lot.

They have better care these days, which means that some cats, which used to live for a maximum of 10 to 13-14 years, can even get to be 20-years-old, for instance. Cancer is more common in older animals, just like it is more common in geriatric human patients.

So, an increase in cancer incidence is the result of a longer life span and more exposure to potentially carcinogenic substances.

Why Are Cancer Stats in Pets Important for People?

Studying cancer in animals can help us better understand human cancer. For example, dogs and people are the single species that, to date, can develop fatal prostate cancer. Breast cancer affects both cats and dogs, and also humans.

Osteosarcoma is a type of bone cancer that affects dogs, but also teenagers. And in the end, there are a lot of studies to be performed on things such as diet, environmental factors, potential exposure to carcinogenic substances, and the incidence of cancer in pets.



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