Top 10 warning signs of cancer in pets

November is Pet Cancer Awareness Month. 

Each year, millions of dogs and cats are diagnosed with cancer, the leading cause of death in pets beyond middle age. 

Knowing what to look for can help with early detection, and as with people, can make a difference. Here are the top 10 warning signs* of cancer in companion animals. If you notice any of these signs in your pet, please consult your veterinarian.  

If your pet is diagnosed with cancer, consultation with an oncologist (specialists in cancer) may be beneficial. At Boundary Bay, we have oncologists who can help treat and manage cancer in your pet so that you and your pet can have more precious moments together.  

      1. Abnormal lumps or swellings that persist or continue to grow: Petting your animal is the best way to find lumps, bumps or swellings anywhere on the body. Any lump on a pet, especially ones that are rapidly growing or changing in texture or shape, should be evaluated. 
      2. Sores that do not heal: Non-healing sores can be a sign of infection or cancer. Your veterinarian can determine the reason why the sore is not healing. 
      3. Weight loss or loss of appetite: If your pet is not on a diet, but is losing weight, illness could be to blame. A loss of appetite is also not normal for pets, and difficulty eating or swallowing can be a common sign of cancers of the mouth and neck. 
      4. Bleeding or discharge: Any abnormal fluid — including vomiting and diarrhea — discharged from any part of your pet’s body should be checked out by a veterinarian. Often tumors of the gastrointestinal tract can cause chronic vomiting and/or diarrhea. Radiographs, ultrasound examinations, and endoscopy are useful diagnostic tools when this occurs. 
      5. Offensive odor: Offensive odors from your pet’s mouth, ears or any other part of your pet’s body, should be checked out. Foul odors are common signs of tumors in the mouth, nose, or anus. 
      6. Hesitation to exercise or loss of stamina: This can be one of the first signs that your pet is not feeling well. 
      7. Persistent lameness: Limping or other evidence of pain is generally associated with arthritis or muscular injury, but unexplained lameness, especially in large or giant breed dogs, is a very common sign of bone cancer. Radiographs of the affected area are useful for detecting cancer of the bone. 
      8. Difficulty urinating or defecating: These problems are likely caused by an underlying health problem. Straining to urinate and blood in the urine usually indicate a common urinary tract infection; if the straining and bleeding are not rapidly controlled with antibiotics or are recurrent, cancer of the bladder may be the underlying cause. Schedule a veterinary appointment if your pet displays any of these symptoms. 
      9. Cough: A dry, non-productive cough in an older pet should prompt chest radiographs to be taken. This type of cough is the most common sign of lung cancer. However, there are many causes of cough in dogs and cats and radiographs can be helpful for evaluation.  
      10. Abdominal distention: When the “stomach” or belly becomes rapidly enlarged, this may suggest a mass or tumor in the abdomen or it may indicate some bleeding that is occurring in this area. A radiograph or an ultrasound of the abdomen can be very useful. 


For more information about cancer and pets, please visit the Animal Cancer Foundation website. 

*Adapted from the Animal Cancer Foundation and Colorado State University College of Veterinary Medicine and Biomedical Sciences websites. 


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