Icon WebMD Expert Blogs

Tales from the Pet Clinic

with Ann Hohenhaus, DVM, DACVIM

This blog has been retired. We appreciate all of the insights that Dr. Hohenhaus shared with our readers.


The opinions expressed in WebMD User-generated content areas like communities, review, ratings, or blogs are solely those of the User, who may or may not have... Expand

The opinions expressed in WebMD User-generated content areas like communities, reviews, ratings, or blogs are solely those of the User, who may or may not have medical or scientific training. These opinions do not represent the opinions of WebMD. User-generated content areas are not reviewed by a WebMD physician or any member of the WebMD editorial staff for accuracy, balance, objectivity, or any other reason except for compliance with our Terms and Conditions. Some of these opinions may contain information about treatments or uses of drug products that have not been approved by the U.S. Food and Drug Administration. WebMD does not endorse any specific product, service or treatment.

Do not consider WebMD User-generated content as medical advice. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare provider because of something you have read on WebMD. You should always speak with your doctor before you start, stop, or change any prescribed part of your care plan or treatment. WebMD understands that reading individual, real-life experiences can be a helpful resource, but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified health care provider. If you think you may have a medical emergency, call your doctor or dial 911 immediately.


Wednesday, January 12, 2011

Twenty-five Years of Mast Cell Tumors

pug with a mast cell tumor

Photo: AMC

Because the Animal Medical Center is in the middle of a big media market, we often host visiting television crews filming our day-to-day operations.  Usually they ask questions about the patients, procedures or equipment they see as they tour the hospital.  This week the Fox News crew asked me a very thoughtful question, “Are veterinarians able to treat pets better now than when you first came to the AMC in 1986?”  Here is an expanded version of the sound bite I gave them.
Dogs develop a tumor, known as a mast cell tumor, which is shown in the photo above on the lip of a Pug dog.  Pugs have a greater risk of developing mast cell tumors than most other dogs.  Mast cell tumors are the most common malignant skin tumor of dogs.  In 1986, we could treat these tumors by surgical excision.

If the tumor could not be removed, we used cortisone.

Mast cell tumors are weird tumors and produce a substance that increases the acidity of the stomach.  The increase in stomach acidity makes dogs with mast cell tumors prone to gastric ulcers.  Intractable gastric ulcers decreased the quality of life for many mast cell tumor patients.  The lack of effective cancer treatments for mast cell tumors and the miserable side effects of the disease made me cringe every time I saw a new patient with this diagnosis.

The situation has improved dramatically since 1986.  First came the development of acid blockers, like Tagamet and Pepcid AC.  These drugs counteracted the acid increasing substance produced by the mast cell tumor.  Dogs could live more comfortably even when we couldn’t eradicate the tumor.

In 1989, the AMC purchased its first radiation therapy machine.  We are now on machine number three.  Radiation therapy was a Godsend for veterinary oncologists and dogs with mast cell tumors.  If a mast cell tumor couldn’t be completely removed with surgery, we could clear up any remaining tumor cells with a few doses of radiation.  Analysis of our patient data in 1996 demonstrated 96% of dogs treated with radiation lived 5 years or more.

More research, some performed at the AMC, identified chemotherapy drugs or combinations of chemotherapy drugs which controlled mast cell tumors which spread distantly from their original site.   Vinblastine, lomustine, cyclophosphamide can all be used in dogs with mast cell tumors.

Advances continue in the area of treating canine mast cell tumors.  In 2009 and again just a few weeks ago, the United States Food and Drug Administration has approved new targeted chemotherapy agents for the treatment of dogs with mast cell tumors, enlarging our repertoire of treatments for this disease.  These new agents, Kinavet (AB Science, France) and Palladia (Pfizer Animal Health, USA) are expected to benefit dogs with tumors other than mast cell tumors and both are being used in cats as well.

This mast cell tumor story is just one of many examples of how veterinary care has improved over the past 25 years , how the AMC has contributed, and why I no longer cringe when I see a dog with a diagnosis of mast cell tumor.

Posted by: Ann Hohenhaus, DVM at 12:02 pm

Subscribe & Stay Informed

WebMD Healthy Pets

Sign up for the WebMD Healthy Pets newsletter and get the latest on food, exercise and health news for Fluffy and Fido.


WebMD Health News