Canine Mast Cell Tumor Treatment with Toceranib

Canine mast cell tumor treatment has recently acquired another powerful tool in fighting this cancer with the drug Toceranib Phosphate, also known as Palladia. This drug fights the mast cell tumor in two ways: 1) by killing the tumor cells themselves and 2) by cutting off the blood supply to the tumors by interfering with the formation of the blood vessels of the mast cell tumor (angiogenesis).

Mast Cell Tumors

Canine mast cell cancer is a common type of cancer. Approximately 6 million dogs are diagnosed with any number of the cancers known to affect dogs. Mast cell tumors account for approximately 20% of all canine malignant skin tumors.

These tumors appear relatively harmless since they are usually small in nature; however, they can appear anywhere in or on the skin in single lumps or in multiples. They can be red, ulcerated, itchy, smooth, bumpy, benign or malignant. They can appear in any breed and usually occur more often in middle-aged to older dogs.

Mast cell tumors are aggressive and can spread to the lymph nodes as well to other organs of the body. Since mast cells are part of the immune system, any disease affecting it can have major health repercussions. Mast cells release toxic enzymes in order to kill any “foreign invaders”, such as infections. Too much of this enzyme for too long can affect the heart rate and/or blood pressure. In addition, these enzymes can interfere with the healing process and can lead to life-threatening disease, including allergies, internal bleeding and gastric ulcers.

Diagnosis of a Mast Cell Tumor in Dogs

A veterinarian will use a variety of tests to confirm the diagnosis of mast cell tumors, including x-rays, blood tests, ultrasound, biopsies and samples of tumor fluid. The tumor will be surgically removed and graded and staged. Grading indicates the extent of the malignancy while staging refers to the spread of the cancer (number of tumors with or without lymph node involvement). Most tumors are Grade I, meaning they are benign and that the survival rate is high.

Prior to Toceranib, treatment involved radiation and/or chemotherapy. This drug can be combined with these treatments for a longer extension and quality of life. Being highly toxic, the use of Toceranib requires frequent trips to the veterinarian as well as frequent monitoring for adverse reactions to the drug. 

Any adverse reactions should stop the use of the drug. These include:

  • Vomiting
  • Appetite loss
  • Diarrhea
  • Black tar-colored feces indicating blood in the stool
  • Blood present in the vomit
  • Unusual bleeding and/or bruising 

Precautionary Measures for Canine Mast Cell Tumor Treatment

Since Toceranib is an anti-cancer drug, it must be handled carefully and with caution. No pregnant or nursing women or children should handle the drug at all. After handling the pills, thorough hand washing is necessary. The use of gloves is recommended. Pills should not be broken and, if they are spit up, they should not be handled with bare hands. Gloves should always be used when cleaning up vomit, urine or feces. Anything soiled by urine, feces or vomit should be discarded. Any messes should be immediately disposed of in tightly sealed trash bags.