Worried That Your Dog May Have Cancer? Here are 19 Dog Cancer Symptoms to Look Out For

We all love our dogs, and they very often become an integral part of our families. As such, the health of your dog is essential, and your loyal companion needs you to look out for it. 

A common condition amongst dogs of all breeds as they age is dog cancer. Years of breathing invisible cancer-causing particles will eventually affect your beloved pet. So, it is imperative that you know and understand the symptoms of this deadly condition, to protect your dog or treat the disease as soon as possible.

Here are nineteen dog cancer symptoms and dog cancer signs to look out for:

19.Prolonged Wounds.


Cuts, scratches, or wounds that are slow to heal, or show no signs of healing, can be a tell-tale sign that your dog has dog cancer. If you notice any prolonged wounds, contact your vet as soon as possible, and get the wounds checked out.

18.Loss of Appetite.


Your dog may lose its appetite for several reasons, some as a cause of illness and others due to stress or psychological issues. Cancer is one potential cause of your dog’s eating habits reducing. You understand your dog best, so if their normal appetite goes down, get them checked out by your vet.

17.Coughing Fits.


Dogs often cough to clear something caught in their throats. However, if they start to cough for no apparent reason, you should consult with your vet, as this can be a sign of lung cancer.

16.Bleeding From the Nose.


Your dog getting a nose-bleed is a visual and often shocking indication that something is wrong. The best person to advise you if this is a sign of dog cancer or not is your vet. So, if bleeding occurs, get it checked out asap.

15.Struggling For Breath.

Dog cancer can present itself through respiratory issues like shortness of breath or gasping for air. Your dog struggling to get sufficient air can also lead to lethargy, sickness, tachycardia, or fever. If you observe your dog struggling for breath, or its breathing being noisy, take it to the vet, as this can be a dog cancer sign.

14.Skin Condition Change.

Another symptom of dog cancer can be changes to your dog’s skin condition. Of course, this can also happen as a result of changes in the weather, diet, or from fleas and parasites. Sometimes, though, it is because of the onset of dog skin-cancer, known as cutaneous mastocytoma. If it is a result of dog cancer, then you may notice skin lesions on your dog. Keep these under close observation, and if there are changes in color or size, consult your vet immediately.

13.Drastic Weight Loss.

Unlike humans, dogs do not obsess about their weight or body image. So, any sudden or extreme weight loss is a sign that something isn’t right. A dog with cancer will often experience drastic or sudden weight loss, so report this to your vet as soon as it is apparent.

12.Pain and/or Discomfort.

Your dog crying, panting, or showing signs of stress for no apparent reason is a sign that something is not right. Dog cancer is often the underlying cause of this pain or discomfort.

11.Fainting or Collapsing.

A dog cancer lump or tumor can cause your dog to have issues with stability. Dog cancer will lead to weakness in your pet, causing it to faint or collapse. If this is happening to your dog, get it checked out by a vet immediately.

10.Mouth Sores or Lumps.

These can often present in your dog’s mouth as a symptom of dog cancer. Check your dog’s mouth regularly and get any lumps or prolonged sores checked-out by your vet.

9.Changes in Behaviour.

Your dog will have set habits, and you are the best person to notice any changes in your dog’s regular behavior patterns. Behavioral alterations can be benign, but sometimes they can be harmful such as scratching, biting, or aggressive behavior. This behavior could be a sign of dog cancer taking hold.

8.Irregular Discharges.

If you notice discharges coming from your dog’s eyes, ears, or nose, then this could be a sign of dog cancer. Get these looked into by your vet as soon as possible.


Seizures are often a symptom of your dog suffering from a brain tumor. If your dog has a jerking fit or foams at the mouth, it could be a sign of dog cancer, so you should immediately contact your vet.

6.Lumps, Growths, or Tumors.

These are often the first image that people have when dog cancer is mentioned. However, very often, dogs can develop benign fatty lumps. If you notice any new lumps or growths appear on your dog’s body, get your dog looked at by a vet to make sure the lumps are not cancerous. 

5.Limping or Lameness.

A cancerous lump or tumor can cause your dog to become lame or start limping. If you notice your dog’s gait alter for no apparent reason, you should consult with your vet and get it checked.

4.Bad Breath.

A dog’s breath is never great at the best of times, but it getting particularly foul-smelling can be a sign of dog cancer onsetting. Take your pet to the veterinary surgeon and get them checked out for possible dog cancer. 

3.Unwillingness to Exercise.

A cancerous lump or tumor might be making exercise painful for your dog. If your dog suddenly loses its enthusiasm for exercise, this could be a sign of dog cancer.

2.General Lethargy.

Only you will be able to tell if your dog has become lethargic, or if it merely has a relaxed personality. If a previously active dog suddenly lazes around a lot, this is a sign that something is not quite right, and it could be dog cancer. Ask your vet to get to the cause of this.

1.Vomiting & Diarrhea.

If your dog is frequently suffering from bouts of vomiting and/or diarrhea, dog cancer could be one of the causes. If it is this disease, you might also notice a swelling of the stomach or abdomen.

Now you know what the symptoms of dog cancer are, you will hopefully be in a better position to protect and treat your dog from this terrible condition.