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Do Microchips Cause Cancer?

Weighing potential risks and benefits

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Microchip close up by HomeAgain Microchips

Microchip close up

by HomeAgain Microchips

The pet microchips and cancer question has surfaced and re-surfaced over the years, causing worry for those who have had their pets microchipped. Is there a risk? Are microchips worth it? Let's look at the pros and cons.

The Pros

  • Millions of dogs, cats, horses, llamas and other animals have been microchipped without any reported problems. (A few people have been microchipped too.)
  • Thousands of animals have been reunited with their people after becoming lost or stolen. According to one microchip manufacturer, 10,000 pets are reunited with their people each month thanks to their microchips.
  • Microchips work even after collars break or tags fall off.
  • AAHA has created the Universal Pet Microchip Lookup site to assist vets, shelters and pet owners in microchip lookup and reuniting pets and their people.

The Cons

  • Potential for injury or infection with implantation.
  • On rare occasion, microchips have migrated to other areas of the body other than the shoulder area.
  • Some animals have been reported to have tumors at the microchip location. Was the tumor caused by the chip? The exact cause has not been proven at this time.

Related: More about microchips

Microchips are a hot topic
From reading various veterinary abstracts, articles and blog postings, I have learned a few things. Mainly, that microchipping is a much-debated topic; ranging from health discussions to the government to possible extraterrestrial involvement. Until now, my focus was simply on animals finding their way back home, unassisted by E.T. or Big Brother.

Do Microchips Cause Cancer?

The main cancer studies cited have involved mice, who don't share the same biological system as dogs and cats. It is unknown if it was the chip material itself or the process of the body dealing with foreign material in the mice studies.

Interestingly, some studies have shown that, like other cancers, certain genetic lines of animals seem to be more susceptible to developing a soft tissue cancer after an injection, implant, trauma or other foreign material is introduced under the skin. Is this microchip-specific sensitivity or predisposition for this type of cancer? The answer remains unknown.

From the American Veterinary Medical Foundation:

"There have been reports that mice and rats developed cancer associated with implanted microchips. However, the majority of these mice and rats were being used for cancer studies when the tumors were found, and the rat and mice strains used in the studies are known to be more likely to develop cancer. Tumors associated with microchips in two dogs were reported, but in at least one of these dogs the tumor could not be directly linked to the microchip itself (and may have been caused by something else)."
and
"We do not recommend that you have your pet's microchip removed, for two reasons. First, based on our review of the studies, the risk that your animal will develop cancer due to its microchip is very, very low, and is far outweighed by the improved likelihood that you will get your animal back if it becomes lost. Second, although implanting a microchip is a very simple and quick procedure, removing one is more involved and may require general anesthesia and surgery."
Read AVMF FAQ

At this time, cases of cancer or other adverse reactions to microchips are self-reported. This means that the veterinarian or pet owner must report the a negative microchip reaction, there isn't a central organization that regulates microchips. Learn more about adverse event reporting.

Are microchips worth the risk?
Other safety devices - seat belts, baby gates, even dog leashes - have had reports of animal injuries or deaths from accidents or improper use. Considering that millions of pets have been microchipped without incident, thousands of lives saved, and the cancer findings (related or not) represent a very small fraction of one percent of the total pets microchipped, I feel that the benefit outweighs any potential risks. I will keep an eye out for new data and developments on this topic.

I found a cat at my house, many miles from home, and was happy to reunite him with his family, thanks to a microchip. It had been several months since he had gone missing; chances are next to nil that he would have ever made it back home without the microchip.

Important Note About Microchip "Helpfulness" in Reuniting Lost Pets
Microchips must be registered with current information - phone numbers, addresses, and other contact information. It is always sad to find a lost pet with a microchip, but with out-of-date contact information. Contact the organization who microchipped your pet or have your pet rescanned at your veterinarians to ensure that your pet's chip information is up to date.

What's your opinion: Is your dog or cat microchipped?

Related Reading:
Frequently asked questions about microchipping of animals - from the American Veterinary Medical Foundation (AVMF)

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