10 Common Signs and Symptoms of Cancer in Dogs

Labrador retriever getting checked for cancer

It’s often difficult to detect cancer early in dogs because, in a lot of cases, problems don’t initially show up in the lab work and a lot of symptoms can be explained away by other things. Swollen lymph nodes, stomach cancer, skin cancer, bone marrow cancer and other cancerous cells are hard enough to detect in humans, let alone dogs and cats. That said, there are some things you can look out for so you know when your pet requires medical attention such as a biopsy carried out by your veterinarian for something that could end up being very serious.

Remember that just because your pet looks and acts normal and healthy doesn’t mean there isn’t something going on and the last thing pet parents would want is to see our beloved furry friends in pain. If you notice any of the following changes, take your dog into the vet even if they’re otherwise acting like their old self.

When dealing with cancer, early detection is key. Here are some symptoms you should be on the lookout for.


1. Abnormal Growths or Masses That Continue to Grow

This is one of the most obvious signs that something is wrong. If you find a bump, lump, or other mass under your dog’s skin, make sure you discuss it with your vet. Most of the time, watching it to see if it grows or spreads is not really the best option. The best course of action is to have the mass removed and biopsied. The best-case scenario is it’s a benign growth but there’s always a chance it can be malignant in which case you can begin to discuss your next course of action.


2. Unusual Bleeding or Discharge

There are certainly a lot of things that can cause bleeding and seeing a little bit of blood doesn’t necessarily mean cancer. That said, it can be an early sign of serious problems and is actually a common sign of cancer in the nose and upper airway. If you notice unexplained bleeding that doesn’t stop or continues to occur regularly, make sure you mention it to your vet.


3. Difficulty with Bodily Functions

If you notice your dog is having trouble doing the things that should come naturally, it’s a sign that there might be a pretty serious problem. Shortness of  breath that occurs without exertion can be a sign of trouble in the windpipe or lungs. You may also notice your dog starts to have a hard time urinating or defecating which can be a sign of trouble in the bladder, kidneys, or digestive system.


4. Offensive Odors

Depending on where the cancer is and how far it’s advanced, you may notice some unusual new smells. This can stem from any number of places, including infected tracts or ruptured masses. Really bad smells don’t always mean cancer, they can also be a sign of a severe infection. Either way, a visit to your vet is in order.


5. Sore or Wounds That Won’t Heal

These sores often occur somewhere on your pup’s skin but can be located anywhere, even hiding out somewhere on the paws or near a nail. If you notice a sore has been there and just isn’t clearing up, talk to your vet. It’s possible that your dog just needs an oral or topical antibiotic or to help. If, after this course of treatment, the sore is still there and doesn’t seem to be improving at all, there may be something else going on.


6. Unintended or Unexplained Weight Loss

Unhealthy, skinny dog

If your pet is losing weight when seemingly everything else has stayed the same, this could be a sign of trouble in their digestive system. When the body stops being able to utilize nutrients from food, weight loss occurs. It could be explained by a tumor somewhere in the intestine that interfering with its ability to absorb and use food.


7. Loss of Appetite

Weight loss and loss of appetite often occur together because a loss of appetite will soon cause your dog to start losing weight. This could happen for a number of reasons but is one of the signs that there may be something blocking the digestive system or pressing against it, making your dog uncomfortable when their belly is full of food.


8. Difficulty When Eating or Swallowing

Difficulty when eating or swallowing will eventually lead to loss of appetite and weight loss but is something you may be able to pick up on its own before later symptoms occur. If you notice your dog starts to feel uncomfortable after eating, has a hard time swallowing, or starts throwing up more often, they’re signs that your dog may have a lump in its neck or a mass pushing somewhere along the digestive tract. Your pooch may very well be hungry and want to eat but may experience pain or discomfort that will eventually lead to a loss of appetite.


9. Loss of Interest in or Reluctance to Exercise

If your pooch was once really active and no longer wants to play or can’t keep up like they used to, there’s a chance that there could be something else going on. Tumors that press against the heart and lungs can really affect your pooch’s stamina. They have a hard time breathing, lose energy quickly, and, at some point, may refuse to participate at all.


10. Persistent Pain that Interferes with Normal Activity

This is one of those symptoms that can mean many things but it’s never good when your dog is in pain, especially when it keeps them from having any quality of life. It’s entirely possible that pain and lameness are caused by an injury but bone cancer can also cause pain in the legs that can prevent your dog from being active.


Early Detection is Essential

Not every illness or injury is the result of cancer but it’s important to be informed and know what to look for in case signs of trouble start to appear. Make sure you keep your eyes open for signs of disease and take your dog to the vet every six months for a regular checkup, especially older dogs. Early detection is key and the best way to do that is to keep on top of your dog’s daily health.


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