Wednesday, July 7, 2010

Do Microchips Cause Tumors?

There have been various stories warning pet owners of the dangers of implanting a microchip in their dogs or cats. One such concern is the development of a tumor.

Do microchips really cause tumor formation in dogs and cats? Probably yes.

Does this stop me from recommending to my clients that their cats and dogs (and other pets) have microchips implanted for their proper identification? No.

Why not? Well, to date the best data we have is from The British Small Animal Veterinary Association which has been tracking adverse reactions to microchips since 1996. They identified a link between microchips and cancer in two dogs of more than 4 million that have received a microchip. To me, this makes it a very rare event.

How would a microchip cause a tumor to form? It is known that irritation, inflammation, and/or wounds are promoters of tumor development. Therefore, virtually anything that causes a local inflammatory reaction may potentially be responsible for initiation of tumor formation.

What about the reports of tumors developing in lab mice that have microchips placed? It is important to remember that mice and rats in those studies were either inbred strains or strains that have been genetically modified to predispose individual animals to cancer formation, making them very prone to developing tumors. Therefore a direct link between what occurs in mice should not be made with what occurs in our pets.

I have not witnessed a case of a tumor at the site of microchip implantation but I have witnessed many cases of pets being brought to our hospital after being found and MOST have no form of identification. There have been a lucky few that had a microchip which our scanner identified. The owner was called and they were shortly reunited with their pet! It is therefore VERY important to remember to make sure your contact information is current, if you have changed your phone number or address since your pets microchip was placed please call the microchip company to update your information.

Other possible risks of microchip implantation include but are not limited to infection, severe bleeding, migration of the microchip and injury to the spine or other organs from the injection. I have not witnessed these events occur at our hospital.

Having a microchip placed in your pet is not a risk- free procedure, but like any medical procedure one must weigh the possible risks of the procedure with the possible benefits. In this case, the occurrence of lost pets is significantly higher than the reported reactions to microchip implantation and therefore in my opinion the benefits outweigh the risks.

Before having a microchip implanted in your pet (or any other procedure) make sure you have a discussion with your veterinarian about the risks and benefits so that you may make an informed decision. If you do feel any bump, lump or growth on your pet, it is important to make an appointment with your veterinarian to have it evaluated.