We have all been either directly affected or know someone who has been affected by cancer. It is a disease that harms thousands of people and there are many forms of cancers our cats and dogs can get as well. Shockingly, one in three people are likely to get some form of cancer. One in four dogs are likely to develop cancer and cats have a one in five chance of suffering from this deadly disease. Around six million new cancer diagnoses are made in dogs alone each year in the U.S alone.

Further, cancer is the number one disease-related cause of death in our pets. With odds like these, we all need to be educated about the kinds of cancer out there, how to recognize their symptoms, and how to treat this terrible disease. As with people, early detection is key. The earlier the cancer is diagnosed, the easier it is to be treated.


Bladder, brain, breast, lung, skin, and testicular cancers are all commonly found in both people and pets. There are certain dog breeds that are prone to particular types. Some cancers to read up on are hemangiosarcoma, lymphoma, malignant histiocytosis, mammary cancer, melanoma, osteosarcoma, prostate cancer, and transitional cell carcinoma.

As a responsible pet guardian, you should be regularly checking your fur baby out for signs and symptoms of cancer. Here are some of the things to watch for.

Appetite Loss or Weight Loss

If you notice a lack of appetite or it seems like Spike is having trouble chewing or swallowing his food, there could be trouble afoot. The presence of tumors can make eating painful, so if your fur baby does have a problem he’ll need to have food with extra nutrients. Further, basic weight loss or even starvation in animals involves the loss of fat. Weight loss associated with cancer cachexia, however, is the loss of both fat and muscle at the same time. You might notice your pup losing muscle definition and looking malnourished, even though they are eating an ample amount of food.

Behavioral Changes

Any kind of depression, irritability, aggression, antisocial tendencies, or lethargy that isn’t normally common in your pet may be a sign of illness; especially for dogs. For cats, lack of grooming as a major indication something might be wrong. Cats are normally obsessive groomers, so if they suddenly show no interest in cleaning themselves, it may be time for a check-up. If you begin noticing changes in your pet’s behavior, take note of how often the change happens, how long it has been going on, and if there are any other changes in their life that may affect their behavior.


Things to look out for can include: altered posture, a chronic head tilt, depression, incontinence, loss of ability to coordinate muscle movements or extreme reactions to sensory stimuli.

Bathroom Changes

Straining to urinate or constipation should be noted and watched. If your cat is avoiding the litter box, for example, you may want to consult a vet. Look for blood in the urine or stool, and if possible, collect a sample for your vet. (It will save your doggy some discomfort later at the doctor’s office.)


Bleeding and Discharge

Diarrhea, vomiting, bleeding, or discharge of pus is an indication something is wrong. Also, check for a distended belly as an indication of fluid retention. If you notice your pet has wounds that are not healing, it could be a sign of a skin infection, but in some cases it is a symptom of cancer, so be sure to check with the vet.

Bumps, Lumps, and Growths

Regularly check your fur baby for any bumpy or knotty areas, especially around the lymph nodes. These areas include the neck, armpits, and around the hind quarters. Anything not traced to an accident or injury can indicate trouble. Keep in mind that as your pet ages, fatty tumors often develop. Your vet can easily do a biopsy (a simple and quick out-patient procedure that removes fluid from the tumor using a needle) to determine whether or not it is malignant. 


Lameness, Stiffness, and Pain

If your cat is suddenly no longer interested in playing, catching the elusive red dot, or appears to be in pain for no reason, she could be suffering from arthritis. Pets that typically develop arthritis are either old or their breed is genetically prone to it. However, lameness, stiffness and pain along with other cancer symptoms can indicate osteosarcoma. If you find your pet is in some sort of pain when they walk or run, you should probably take them to the vet to check it out if it persists for a few days. While there are can be many different causes for their pain, if it is cancer related, you definitely want to catch it early.

Respiratory Problems

Coughing, wheezing, or any difficulty breathing is an indication something is wrong. Pay special attention to anything that is coughed up and look for traces of blood that might denote lung cancer. Remember, pets can also have respiratory allergies like people do, so account for any environmental factors that could be causing their discomfort before getting too freaked out that your pet has cancer. However, if they are coughing up blood, that is not a common allergy reaction and should be given immediate attention.

Sores and Wounds

Puppies play and often play rough, but if your pet has sores that appear from nowhere or seem to just never heal, there’s a reason. Monitor progress closely because this could indicate a compromised immune system, skin cancer, or mast cell tumors.

Strange Smells

Highly offensive odors coming from your pup’s mouth, ears, or nether regions can be caused by cancer. We’re not talking about a single occurrence of bad breath or stinky gas, but something that is ongoing over the course of more than a day or two. Cancer of the mouth, ears or anal regions can result in foul odors.

Keep Calm and Consult a Professional

In the event that your pet is displaying any of these symptoms, always note when it started, how long it has been going on, severity ranges, other potential causes and effects so you can provide your vet with as much information as possible at your pet’s appointment.

Also keep in mind that geriatric pets are prone to disease and cancer, so pay special attention to your senior fur babies. As a general rule, dogs over the age of seven should have a yearly exam! Because prevention and early detection are so important, it’s better to err on the side of caution. Better safe than sorry!


Image source: Tambako the Jaguar/Flickr