There are many cancers that invade the animal world, and the type of cancer dictates the type of therapy used to eradicate them from the body. Available tests enable veterinarians to confirm or eliminate a diagnosis to determine appropriate treatment options.

4 Current Animal Cancer Treatments

• Surgery
• Removes or reduces the cancerous tissues so therapies are more effective
• Best for cancers that are confined in an area and in an accessible site
• Special forms of surgery
• Cryosurgery  - surgical use of liquid nitrogen to kill and destroy cells upon contact
• Electrosurgery – surgical use of electrical currents to scrape and cauterize tissues
• Light Amplification by Stimulated Emission of Radiation (LASER) – surgical use of carbon dioxide lasers that focus a light to vaporize cancer, sterilize site and seal blood vessels
• Early diagnosis and intervention are important
• May require referral to a specialist
• Risks include:
• Anesthesia
• Bleeding
• Pain
• Chemotherapy
• Uses drugs to kill cancer cells
• Used when cancer is widespread, or when there is risk for spread from initial location
• Two forms:
• Systemic chemotherapy – oral or injected drugs that treat throughout the body
• Chemotherapy – drugs that are designed to cause selective damage to cancer cells
• Not all cancers respond to chemotherapy
• Risks include:
• Nausea
• Lowered immunity
• Can damage healthy cells
• Anemia
• Gastrointestinal upset
• Bleeding problems
• Radiotherapy
• Use of specially calibrated high-energy radiation to focus on cancer tissues and injure the DNA of cells
• Not all cancers respond to radiation
• Location of cancer may make this therapy impossible to use
• Treatment done by specialist
• Often used in combination with surgery and chemotherapy
• Two main types of radiotherapy:
• External beam – treats from the outside of the tumor
• Interstitial brachytherapy – process implants or injects a radioactive isotope inside the tumor, causes pet to become temporarily radioactive.
• Risks include:
• Lowered immunity
• Can cause damage to normal healthy cells such as intestinal lining, bone marrow and immune system
• Anesthesia
• Tissue sloughing
• Brachytherapy requires the treated animal to be kept isolated until radioactivity reaches a safe level
• Hyperthermia
• Uses heat probes or radiation to destroy cancer tissues by exposing tissue to high temperatures
• Not all cancers respond to hyperthermia
• Location of cancer may make this therapy impossible to use

Recent Advancements in Treatments for Cancer in Animals

Up until recently, veterinarians have had to defer to cancer treatments that were developed for use in humans rather than for animals. Because of this, the safety and effectiveness of the treatment’s use in animals was unknown. However, in 2009, the U.S. Food and Drug Administration (FDA) approved Palladia (toceranib phosphate) as the first drug for the treatment of mast cell tumors (MCT) in dogs, the second most common type of canine cancer. Palladia was first made available for purchase in 2010, and its use is becoming widespread.

• Palladia works to treat MCT that may or may not have regional lymph node involvement.
• Tests show Palladia’s use is effective in MCT that has passed the first stage, and that its use is less invasive than surgery, which is the most common cancer treatment approach for MCT.
• Palladia works by killing the tumor cells and cutting off the blood supply to the tumor.
• Common side effects:
• Decrease or loss of appetite
• Weight loss
• Lameness
• Diarrhea
• Blood in stool
• Cats treated with Palladia have shown responses in MCT, squamous cell carcinomas, and vaccine-associated sarcomas.

The only drug fully approved by the FDA for the treatment of cancer in canines is Palladia. However, the FDA has approved two other drugs to treat mammary carcinoma and squamous cell carcinoma cancer in dogs:

• Kinavet-CA1
• Conditionally approved by FDA in 2010
• Paccal Vet-CA1
• Conditionally approved by FDA in 2014.

There are no FDA-approved or conditionally approved cancer treatments specifically for cats at this time.