Five dogs of different breeds are lined up, each showing various expressions. From left to right: a chocolate Labrador, a Jack Russell Terrier, a Bulldog, a Pug, and a Beagle.
20% Off
New Dog
Boarding Clients!
Valid 01/01/24 thru 02/28/24
Logo of fon jon pet care featuring a brown cartoon dog with a green tennis ball and text highlighting 70 years of pet care services in san diego.
cat with cancer

Pet Cancers in Cats and Dogs

cancer in dogs
Early detection of a cancerous tumor in your pet can increase the chances of successful treatment.

One of the most heartbreaking diagnoses a pet owner can hear is that a beloved family pet has been stricken with a terminal illness. Like humans, cats and dogs can fall victim to cancerous tumors that can quickly be fatal. Luckily, if the disease is caught early enough, there are excellent treatments available for pets of all sizes. Read on to learn more about the most common types of cancer found in pets and the telltale symptoms.


Lymphoma affects both feline and canine animals. This form of the disease consists of cancerous tumors that affect virtually any body organ. Because lymph nodes are present throughout the body, the cancerous cells may grow in a way that is difficult to detect. Signs of Lymphoma include lack of appetite, increased lethargy, weight loss, vomiting, and diarrhea. Should a pet suddenly fall ill, the owner should track the amount of time it takes to recover. An animal that stays ill for longer than one week should be seen by a veterinarian.


Osteosarcoma is a growth of cancerous cells in the animal’s bones. A cat is most often affected by this disease in the shoulders and legs, though it can appear anywhere. A dog is often affected in the legs as well, though osteosarcoma is more common in larger breeds than in smaller pets. Animals that begin favoring their legs or limping may be affected by a tumor. Other signs of bone cancer are unexplained swelling, inability to walk and sometimes bloody nose or excessive sneezing.

Breast Cancer

Older animals may develop tumors in their mammary glands. Many of these tumors are benign. However, it is always advised to have even benign tumors removed. This type of disease is most often found in female pets over six years old who have not been spayed. It is also prevalent in animals who were spayed later in life. Symptoms present similarly to those in humans. Lumps, soreness, and unexpected secretions are all cause for alarm.

Malignant Melanoma, Squamous Cell Carcinoma, and Mast Cell Tumors

Sunblock is not commonly used on pets. This is unfortunate because, just like their owners, these pets can develop cancerous cells on their skin. Symptoms are generally limited to growths and changes in skin appearance, especially on those areas that are not covered by hair. Though many growths are not malignant, it is very important to have any change in skin appearance examined by a veterinarian. If caught early, pets have an excellent chance of survival.


cat with cancer
Osteosarcoma in cats often affects the shoulders and legs, though it can appear anywhere.

Hemangiosarcoma almost exclusively affects dogs, though it can rarely appear in cats. This disease affects the lining of blood cells. Signs of hemangiosarcoma include abdominal swelling, weakness, lethargy, nosebleeds and lack of appetite. Unfortunately, it is possible for none of these signs to appear. Many pet owners do not worry about their pets’ health until the animal collapses from an internal hemorrhage.


Treatments vary depending on the extent and type of disease. In most cases, veterinarians will attempt to remove any tumors through surgery. Pets may be offered chemotherapy or radiation treatments to kill the cancerous cells. Pets that are in advanced stages of the disease may be offered treatments to ease the pain, but they are unlikely to recover to full health. Many pet owners are faced with the sad choice to extend the pet’s life or to euthanize in order to relieve suffering. A veterinarian is able to offer expert opinions, but it is always up to the pet owner to decide.


Pet health starts with regular checkups, healthy diet, and exercise. Animals that are obese may have a higher risk of developing a disease. The same is true for those who have diets that are high in fat. To observe the best in pet health, owners should take the same precautions with the pets that live in their homes as they do with themselves.

The information provided in this article is intended for general informational purposes only and does not constitute veterinary advice. While every effort has been made to ensure the accuracy and reliability of the information presented, it should not be considered as a substitute for professional veterinary guidance. Always consult a qualified veterinarian for specific advice tailored to your pet’s individual needs and health condition.

a group of dogs sitting next to each other.

20% Off
for New
Boarding Clients!
*not applicable during major holidays

a blue rectangle with a blue background.

Petcare articles

view all articles
A human hand gently holding a dog's paw, with green grass in the background.
June 7, 2024

How Hot Does the Weather Have to Be for Pavement to Burn My Dog’s Paws?

As the summer heats up, many dog owners are very aware of the risks that the heat can pose to their furry friends. We usually think about giving our dogs plenty of water and shade to stay cool, but the…

pet groomer shaving Maltese dog fur
June 4, 2024

Shaving Dogs for Summer – The Difference Between Double and Single Coated Dogs

Shaving Dogs for Summer – The Difference Between Double and Single Coated Dogs People who own dogs often wonder if shaving their dogs is the best way to keep them cool in the summer. There are, however, some things you…

staff of dog boarding facility welcoming dog
May 8, 2024

What to Expect When Dog Boarding for the First Time

You and your canine companion have taken a giant leap forward when you decide to board your dog for the very first time. It’s normal to have a range of feelings, from anticipation of your trip to worrying about your…

sad Cocker spaniel dog looks through wooden fences in dog boarding
May 7, 2024

Dog Boarding Red Flags, How to Choose the Right Place for Your Pup

Leaving our beloved pets behind, even for a brief period, can cause anxiety for any pet parent. Finding a reliable kennel for your dog is essential for their comfort, safety, and well-being whether you’re leaving for a weekend or a…

Two volunteers in matching t-shirts smile as they play with a pug in front of a house.
April 5, 2024

Pet-Friendly Evacuation Shelters in San Diego

Handling emergencies involving pets can be challenging. One way to help keep your pets safe during a natural disaster such as flooding or fires we recommend is having a list of pet friendly shelters in your pet’s emergency go bag…

dog being rescued by an old man
April 5, 2024

Tips for Finding a Lost Pet After a Natural Disaster

Finding a misplaced pet after a natural disaster might seem like a daunting task. However, there are effective strategies and resources that can increase the chances of a happy reunion. Our goal is to provide you with practical tips that…

A dog laying on a towel with a first aid kit.
March 6, 2024

Preparing for Disasters: Tips & Dog Emergency Kits

It is our responsibility to ensure the safety and well-being of our pets during times of crisis or natural catastrophe. Many of us consider our beloved pets more than just animals; they are loved ones who complete our families and…

female owner carrying her orange cat
March 6, 2024

What is Positive Reinforcement Cat Training

Some folks claim that training a cat is impossible. They are completely mistaken. Cats are true experts when it comes to training; in fact, they have the whole concept nailed. Just consider how they’ve conditioned YOU to satisfy their every…

dog yoga with owner
February 2, 2024

Indoor Exercises for Dogs When the Weather is Bad

Guide on Indoor Exercises No matter how bad the weather gets, your beloved pet still needs their daily dose of play and exercise. It is our belief at Fon Jon Pet Care that your dog needs regular indoor exercise and…

A jack russell terrier sitting on a doormat with the word "home" written on it, looking directly at the camera.
February 2, 2024

Tips on How to Help with Separation Anxiety in Puppies

Puppy separation anxiety is a typical problem that many pet owners encounter. When a puppy is afraid of being alone, it may exhibit this behavioral problem. If you care about your pet’s health, you must learn about this issue and…

dalmation dog with happy new year headband
January 4, 2024

Dog Owner New Year Resolutions 2024: How to Make Your Dog Happy

With the arrival of the new year comes an ideal opportunity for dog owners to make resolutions that prioritize the happiness and health of their beloved pets. Both you and your dog will benefit from an uptick in the quality…

sick dog with ice pack on top of his head
January 4, 2024

Sick Dog Symptoms: Learn What to Watch For

If you are a dedicated dog owner, you have a responsibility to keep an eye on your pet’s vital signs. Being able to identify the signs of a sick dog goes beyond simply treating them when they’re sick; it also…

Have a

Get a response within 24 hours

Valid 01/01/24 thru 02/28/24

Don’t Miss Out on our New Specials!

20% OFF

new dog boarding clients

A small brown and white dog sitting on a white background.

50% OFF

new cat boarding clients

A tabby cat waving its paw in the air.

20% OFF

new dog daycare on first package purchased

Two dogs sitting next to each other on a white background.

50% Off For New Cat Boarding Clients!

Request Your Boarding Dates

20% Off For New Dog Boarding Clients!

Request Your Boarding Dates