Almost one in four dogs and one in five cats will develop cancer in their lifetime. Billings Animal Family Hospital has a history of treating cancer, and can provide support for you, and state-of-the-art medical care for your pet. If your pet has been diagnosed with cancer, here are our answers to some questions that pet owners commonly ask.  

What is cancer?

Cancer is the abnormal growth of body cells. Normal cells continuously multiply and then die when they are worn out or damaged, but unrepaired mutations during the replication process can allow some cells to multiply without stopping. Any cell in the body has the potential to become cancerous, including the skin, internal organs, immune system, or blood. Cancerous cells can also leave their primary development site and travel to other body locations (i.e., metastasize).

What are cancer signs in pets?

Cancer signs vary based on the body tissue involved and the disease severity, but some possible cancer signs in your pet include:

  • Lumps, bumps, or discolored skin
  • Non-healing wounds
  • Changes in weight
  • Unexplained lameness or swelling
  • Difficulty eating
  • Difficulty breathing
  • Bleeding from the mouth, nose, or other body openings
  • Abdominal swelling
  • Chronic diarrhea or vomiting

What causes cancer in pets?

A multitude of factors may influence cancer development, and the reason why some pets are affected and others are not is unclear. More than 50% of older pets develop cancer, possibly because the aging process interferes with the repair of cell replication mutations. Pets can be exposed to carcinogens, such as second-hand smoke, ultraviolet rays, or chemicals. Up to 30% of cats infected with the feline leukemia virus eventually develop cancer. Hereditary factors also can play a significant role, with certain dog breeds especially susceptible to cancer. Chronic inflammation, such as previous bone fractures, obesity, or gastrointestinal disease can trigger cancerous cells. Research studying the relationship between spaying and neutering and cancer, especially in large-breed dogs, is ongoing.  

What cancer types affect pets?

Dogs and cats can develop many cancer types, but the more common forms include: 

  • Lymphoma — An immune system cancer affecting the lymph nodes, bone marrow, spleen, skin, eye, nervous system, or gastrointestinal system in dogs and cats
  • Mast cell tumors — An immune system cancer on the skin that may also occur on the spleen or other internal organs
  • Melanoma — A tumor of pigment-producing cells that commonly develops in the oral cavity, but may also occur on the lips, vulva, anal regions, and toes
  • Squamous cell carcinoma — An epithelial cell tumor that often develops in the oral cavity, and on the nose or skin 
  • Osteosarcoma — A bone cancer that can affect any bone, including the limbs, pelvis, spine, skull, sinuses, or oral cavity
  • Hemangiosarcoma — A blood and skin cancer affecting the skin, spleen, liver, or heart 
  • Mammary adenocarcinoma — A mammary tissue cancer in dogs and cats, more common in unspayed female animals, or those spayed later in life
  • Transitional cell carcinoma — A urinary tract cancer affecting the cells lining the bladder wall and urinary system

How is cancer diagnosed in pets?

At Billings Animal Family Hospital, we will thoroughly examine your pet, review their medical history, and, if we suspect cancer, perform additional testing that can help us reach a diagnosis. Tissue samples or needle aspirates of a tumor are often diagnostic for specific cancer types, while others may require X-rays, blood tests, ultrasound, advanced imaging, or exploratory surgery for a confirmed diagnosis. Your pet’s cancer will then be staged to determine the severity, whether the cancer has metastasized, and how responsive the cancer may be to treatment protocols.

How is cancer treated in pets?

The specific type, severity, and cancer stage dictate the treatment plan, with each pet requiring an individualized approach. Cancer treatment can include a single therapy, such as complete surgical removal of a tumor, or require chemotherapy, radiation, or immunotherapy. Unlike humans, the majority of animals undergoing chemotherapy do not develop serious side effects. Certain cancer types can be surgically cured, whereas others are medically managed to provide remission and a good quality of life before cancer eventually returns. We also consider your pet’s nutrition, pain management, and support for their overall health and well-being during treatment.

The Billings Animal Family Hospital team knows that the “C” word can be frightening when your pet’s health is involved. We are here to help you through the process, and we encourage you to contact us if you have any questions or concerns.