Signs of Cancer in Dogs: What to Look For

signs of cancer

Our dogs are family members. We laugh with them, celebrate momentous occasions, and watch them enjoy life. When we think of the idea of them getting an illness like cancer, it is absolutely devastating. While dogs are susceptible to the same types of cancers as humans, they can metastasize at a much faster rate. It is an unfortunate fact that half of all dogs over the age of 10 will develop some sort of cancer in their lives. Pay attention to the signs of cancer just in case.

While the thought of cancer is scary, noticing the signs of cancer early is important. Dogs routinely live past the age of 10, showing just how far veterinary medicine, as well as pet care, have advanced in recent years. Just like in humans, half of all cancers are curable if they are caught early. That’s why it is extremely important to know what signs of cancer to look for in dogs so we know when to seek medical help.

Common Signs of Cancer in Dogs

Unexplained Weight Loss or Gain

If you notice that your dog is losing weight either rapidly or slowly without a reduced diet or exercise, call the veterinarian. A cause of this could be a tumor along the intestine. This is the most common sign of cancer in dogs. Also, sudden weight gain or bloating could signal a serious problem. If the dog is maintaining his or her regular appetite and exercise routine, yet is gaining weight, make an appointment with the veterinarian.

Collapsing, Weakness, or Lethargy

If your dog should collapse, seek medical help immediately. Collapsing, weakness and general lethargy can be signs of cancer in dogs. If your dog falls down, and then seems better the next day, still seek help because this can indicate a tumor of the spleen. If you notice unusual behavior, you may want to call the veterinarian. For example, if your once happy and excited dog suddenly seems to lose interest in activities they once enjoyed or perhaps stops greeting you at the door each day, this could be a sign of cancer. Keep in mind that lethargy is different from fatigue. Excessive sleep and delayed responses to visual and auditory stimuli can indicate a problem, so if your dog suddenly seems a lot less active for an extended period of time, seek help.


While coughing isn’t always a sign of cancer in dogs, a persistent cough that lasts for more than a few days could be a cause for concern. It may be a sign of lung cancer.

Changes in the Mouth

It is a good idea to take a look inside your dog’s mouth every few weeks, perhaps when they yawn or eat. If you notice sores, lumps, a strange odor, bleeding, or a change in gum color it can be a sign of oral cancer, particularly in older dogs. Often, this sign goes unnoticed. Check regularly, especially if you have a dog of advanced age, and notify the veterinarian if you see any changes.


Nosebleeds in dogs are never normal. Particularly in older dogs, this could signal cancer of the nose. However, no matter the age of the dog, if a nosebleed occurs, seek medical help.


Seeing your dog have a seizure can be extremely distressing. As this can be a sign of a brain tumor, notify your pet’s doctor immediately if you see your dog having sudden and uncontrolled bursts of activity, like chomping and chewing, jerking of the legs, or foaming at the mouth.

Changes in the Skin

Make a habit of checking your dog’s skin frequently. If you notice lumps, bumps, or any sort of change, it can be signs of cancer. Whether benign or cancerous, it is best to find it early and have it treated, so be mindful of changes when you pet your dog. Also look for sores that won’t heal or lesions that seem itchy or painful. This can indicate abnormal cell growth. If you notice abnormal lumps or swellings that persist or continue to grow, call the veterinarian.

General Pain or Signs of Discomfort

No one knows your dog better than you do! If he or she seems to be in pain, such as if they cry out when touched, or just seem uncomfortable, make an appointment with the veterinarian as soon as possible. Signs of discomfort when eating can signal mouth cancer, so be aware of this as well.


Persistent discharge from the nose or eyes can indicate a problem. If you notice a nasal discharge or eye discharge, call the veterinarian immediately. These signs can signal facial or eye tumors.

Sudden Lameness

Lameness presents as tenderness and subtle pain, limping or favoring a limb, or in severe cases, the inability to place any weight on the limb. It refers to any changes in your dog’s gait. If you notice pain that persists, it could be a sign of bone cancer, so have it checked.

Unusual Bowel Movements

You see your dogs output each day, so be aware of anything that doesn’t seem normal. Persistent diarrhea, hardened stools, and straining can all be symptoms of illness. In particular, if you notice black, tarry stools, call the vet immediately as this can signal a tumor.

Difficulty Breathing or a Change in Bodily Functions

A common sign of cancer in dogs is when normal bodily functions become painful. If you notice difficulty breathing, straining, or any signs that the dog is uncomfortable during normal activities, this could be a warning sign. Call the veterinarian as soon as possible.

Noticing the early signs of cancer is one of the first steps in helping your dog live a long, healthy, and active life. Always provide an appropriate diet, exercise and mental stimulation for your pet. Whenever you notice anything unusual, don’t hesitate to get it checked out by an expert veterinarian. Early detection is best, especially in dogs of advanced age. Always track your dog’s health, and seek help when needed. The professionals at Tipp City Veterinary Hospital are here to help, so contact us with any questions you may have.

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Charlene Robinette
Charlene Robinette
posted 2 months ago

We were extremely happy with our experience at Tipp City Veterinary Hospital. They were able to get us in on a Sunday, when our dog was very sick and needed to be seen that day. The staff was friendly, courteous and helpful. Dr. Ken was wonderful! He was gentle, but thorough when he examined our dog. He diagnosed the problem and patiently answered all our questions. His treatment was effective and our dog was feeling much better within 24 hours. We would definitely recommend Tipp City Veterinary Hospital.

Traci Eaton
Traci Eaton
posted 1 month ago

My dog survived cancer a year ago. He also had 2 separate infections that were only treated with a certain antibiotic. Recently he had symptoms similar to the last time. Dr Jim did an ultrasound and confirmed he was fine. He calmed my anxieties, completely understood my fears and was completely kind about it.

The only thing I hate about Tipp Vet is they are a little pricey. Overall I've had good experiences for the last 2 years.

After being to a vet in Englewood whom just strung me out for money & never had answers. I went to a specialist & ended up spending over $3,000 just to find out it was a simple diagnosis and with surgery to cure the cancer. I really recommend this place.

Susan Bailey
Susan Bailey
posted 5 months ago

Amazing Boarding facilities! Immaculately clean and odor free! They provided us with a tour prior to our first boarding so we could make an informed decision about who to trust with the care of our little guy. Everyone has had that one experience where they can't enjoy their vacation because they are worried if their pet is being taken care of properly! We now can actually enjoy our time away knowing that our little pup is very well taken care of! And they have a text line you can use for updates! They make you feel like your pet is just as important to them as they are. to you. Give them a won't be sorry! If Barkley could talk, he would say... I'm a happy camper! Thank you mom and dad for bringing me here!

Amy A
Amy A
posted 1 month ago

My dog was critically ill with a ruptured gallbladder. Time was running out. My vets didn't have the capability to do a surgery like that on my Angel. Someone told me about Tipp City Vet Hospital, and I called them immediately. They brought Angel in as an emergency, and Dr. Jim stayed late to operate. He said it was the worst case of infected gallbladder he had ever seen in his career. Thanks to Dr. Jim and the wonderful staff at this hospital, Angel survived. Two weeks later, she's been through three different antibiotics, and she is great! Was it expensive? Yes. Was it worth it? Absolutely. My sweet dog is back to patrolling the yard for squirrels. I highly recommend this hospital if you have a pet who is critically ill, or if you just need to find a new vet! I can't say enough good things about this place.

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