Today we’ll be sharing the 10 early warning signs of pet cancer from the Veterinary Cancer Society in recognition of Pet Cancer Awareness Month.

If you notice any of these signs, be sure to make an appointment with us right away so that our veterinarians can do a complete physical examination on your pet. It is important to remember that while these can be warning signs of cancer, they can also indicate other health problems as well – if your pet has one or more of these symptoms it does not automatically mean he or she has cancer. That is why it is so important to bring your pet in for an exam and diagnostic testing.

Pet Cancer


Swollen Lymph Nodes

Enlarged lymph nodes can indicate a type of pet cancer called lymphoma. The easiest lymph nodes to palpate are the submandibular lymph nodes which are located behind the jaw; and the popiteal lymph nodes, located behind knee. A normal lymph node is usually soft and small, about the size of a pea. When lymph nodes becomes swollen, firm, or painful a biopsy is recommended.

Unusual Lump or Bump

Any mass that appears suddenly and is rapidly increasing in size or changing texture or shape should be biopsied. Mast cell tumors have a variety of appearances; the only way to know for sure whether a tumor is malignant or benign is to look at the cells under a microscope.

Abdominal Distension

A mass or tumor in the abdomen can cause the belly to become rapidly enlarged. It can also become distended when there is bleeding in the abdomen. Abdominal radiographs or ultrasound are indicated.

Chronic Weight Loss

Any time your pet starts losing weight without being put on a diet is a cause for concern. Unexplained weight loss does not always equal cancer, but can be a sign that something is wrong and should be investigated further.

Chronic Vomiting or Diarrhea

Tumors of the gastrointestinal tract often cause chronic vomiting and/or diarrhea. Diagnostic testing can include blood work and abdominal radiographs.

Unexplained Bleeding

Any unexplained bleeding should prompt an examination by your veterinarian. Bleeding or bruising, especially in an older pet, can be indicative of cancer.


The presence of a dry, nonproductive cough in an older pet is the most common sign of lung cancer. Chest radiographs aid in diagnosis. However, remember that there are many causes of cough in dogs and cats.


Sudden lameness, especially in large or giant breed dogs is a common indication of bone cancer.  Radiographs of the affected limb can be a great diagnostic tool in detecting this type of pet cancer.

Straining to Urinate

Although straining to urinate or blood in the urine often indicates a urinary tract infection, when it is recurrent or unresponsive to antibiotics this can mean bladder cancer.

Oral Odor

A bad odor coming from the mouth can indicate an oral tumor. In addition, your pet may have difficulty eating hard kibble or a loss of appetite. These tumors are difficult to detect without sedation – another reason it is important for your pet to get regular dental cleanings.