Microchipping Your Dog – What’s the Risk?

Dog getting his immunization shotThis week has seen a number of news articles reporting that your dog has an increased risk of cancer if he is microchipped. According to the articles, sarcomas – malignant tumors – can develop at the site where the chips are implanted.

Some of the articles have been sensational in nature, and there are reports of dog owners taking their dogs to the vet demanding to have microchips removed purely on the basis of what they’ve read in the press.

As responsible dog owners, we need to know all the available information so we can make an informed decision on whether or not to have our dogs microchipped, or if they are already microchipped, to have the chips removed.

Here are the facts as I understand them:

What has the fuss been about:

The United States’ Food and Drug Administration (FDA) approved the implant of microchips in humans in 2005 on the basis that it found “reasonable assurance” that microchips are safe.

However, neither the FDA nor VeriChip Corporation (who make the microchips) has publicly disclosed that a number of studies in the mid 1990s identified that microchip implants had caused malignant tumors in laboratory mice.

Both the FDA and VeriChip are denying they knew of the existence of these studies, despite the fact that the results were published in a number of veterinary an toxicology journals.

What were the findings of the studies done in the 1990s?

A 1997 study in Germany found 1% of 4,279 micro chipped mice developed cancers that, according to the authors, were “clearly due to the implanted micro chips”.

A 1998 study in Ridgefield, Connecticut reported that just more than 10% of 177 microchipped mice developed cancer, and this result was considered “surprising”.

In addition, a 2006 study in France found that 4.1% of 1,260 microchipped mice developed tumors. The study was not testing for the development of tumors, and as the discovery was incidental, the results may be underestimating the true occurrence.

Whilst none of the studies had a control group of mice that did not get microchipped, cancer specialists still maintain that the research raises a red flag on the link between between microchips and the malignant tumors that were found; in most cases the tumors were encasing the implant.

What’s the risk to dogs?

Apparently it’s easier to induce to cancer in mice than it is humans, and the inference is that dogs lay somewhere between mice and humans. Therefore the chances of your dog developing a malignant tumor from a microchip implant probably aren’t as high as the studies noted above. However, no research has been done to prove this one way or another.

Dr. Cheryl London, a veterinarian oncologist at Ohio State University, has noted that tens of thousands of dogs have been chipped, and veterinary pathologists haven’t reported outbreaks of related sarcomas in the area of the neck where the implants are usually done.

The Associated Press conducted a four month research into microchips and health and only identified two cases where chipped dogs developed malignant tumors at the site of the implant.

Leon, a French Bulldog is probably the most well known dog to have suffered from a sarcoma due to the publicity a memorial web site to him has received.

However, Leon’s owner states that the same day Leon received his chip he also had a vaccination near the same site as the implant. Given that vaccinations can often induce sarcomas, it’s not 100% certain that Leon’s tumor was caused by the microchip.

In the light of the available evidence, it appears that the risk of your dog developing a sarcoma is very low.

What’s the alternative to microchipping?

A dog should have some form of permanent identification – collars and tags simply aren’t reliable enough.

Tattooing is an alternative, but if your contact details change, then it’s harder to update these on your dog. With a microchip the new information can easily be scanned into the chip.

What can I do if my dog has already been microchipped?

One way to monitor your dog for the development of a sarcoma is to routinely check for lumps in the area where the implant was done.

Microchips can move, so it’s recommended that you check the area from elbow to elbow over your dog’s back.

To microchip or not

The evidence indicates there is some risk of your dog developing a malignant tumor following the implant of a microchip.

However, this has to weighed against the chances that your dog might get lost.

Dogs can easily become separated from you – think of how quickly a dog can run off after a car accident or house fire, or after being spooked by fireworks; natural disasters such as Hurricane Katrina saw many owners separated from their pets.

If your dog has some form of permanent identification, the chances of the two of you being reunited are much higher.

Less than 50% of lost pets are reunited with their owners – many pets find their way to animal shelters but if they have no form of identification there is a high probability they will be euthanized if they’re not claimed or adopted within a few days of arriving at the shelter.

For me, microchipping is the only option for my dogs because the risk of losing them is far higher than the chances they will develop a chip induced sarcoma.

Whatever you decide to do, at least you now have all the facts with which you can make a decision.

[tags]dogs and microchipping, sarcoma associated with microchipping, malignant tumor, microchipping risks[/tags]

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  1. Great post Clare! Thanks for setting it straight. Complicated bunch of info out there. And thanks for barking into Dogster about my Puppy Mill Awareness Day post. It will really help get he word out.

    Licks, Johann

  2. This is, indeed, a hot topic. I wanted to share another way to help locate and track lost pets that puts the pet owner in control of reuniting with a missing pet. I work with LovemypetsGPS who provides GPS systems and safety collars, leashes and harnesses that are affordable, lightweight and non-intrusive.

    See http://www.lovemypetgps.com for more information.

    Hope this is helpful.

  3. Hello, i didnt even know that dogs were implanted with microchipped as an identification, learned something new today. Great post!

  4. Hi Rachel – thanks for your comment.

  5. This is all really great information. I also know of a great way to protect your pet, it’s called helpmefindmypet.com. This service includes a duel registration as well as a Lost Pet Alert. This alert is amazing it can be sent in a matter of seconds. When your pet goes missing you just login to your account report the pet with a description of what, when, and how, and instantly a alert poster is generated and sent out to Vets, Shelters, Rescues, Municipalities, Members, and the pet friendly community. They are proven to work and everyone should check out there testimonials. Once again that’s helpmefindmypet.com, good luck everyone.

  6. great info thanks!

  7. For those of you who say it is worth the risk to microchip your dog versus the risk of losing them…..you haven’t been through what I just have. My dog developed a one pound tumor in between her shoulder blades, and it was identified as a sarcoma. It took almost 3 hours for them to remove it, and the tumor was attached to her vertebral processes. When I arrived at the vet, I asked if the microchip could have been part of the problem. The vet scanned my dog, and there was no microchip. He called the pathologists office to see if they would scan the tumor……and that is exactly where the microchip was. So, beware of microchips in your animals!!!!

  8. Teresa Carney says:

    My shetland sheepdog just had surgery for a tumor Friday 25th. During the removal of the tumor which has grown to the size of a golf ball out popped his microchip under the mass. My family is heartbroken to even think this could be cancerous. We should have the biopsy back this next week to find out. His microchip had traveled down to his lower shoulder. Not a spot your would think it would be. So there are pros and cons but hopefully this one turns out o.k. I will keep you updated. They Carney Family

  9. Sonya, I am sorry to hear about your pet. I am still not 100% convinced that the microchip itself caused the honorable cancer but it may be what help introduced the cancer or a point to where the cancer in the body could attach and grow. I feel if the chip from the manufacture itself was not 100% sterile, this could cause cancer growths to develop as part of the body trying to get rid of a foreign material in the body. This would be like the body trying to reject the device. Maybe the manufactures of the devices and the drugs labs should look at a drug to give to the pet after the injection of the chip to help “rejection”. Just like given to people after an organ transplant. It is only my thoughts, I may be way off base. I am one of the lucky people who had a pet returned because of the microchip, My dog had lost one of his ID tags, the rabie tag was the wrong one (mix-up at the Vet). There was one issue with the chip company, they entered my secondary contact information incorrectly. The miss-typed all of the information off by one character on the key-board (one character to the left).

    Teresa – any update on your pet ?

  10. Great post! Im glad i read this, because i was just looking up where i could get my dog microchipped, and this article was in the search results. I clicked on it, thinking this is prob a bunch of junk. But when i read it, i was amazed!
    Im sooo glad you put this up for everyone to see.
    Thanks again,

  11. Linda Hawkins says:

    Our little 5 year old Yorkie has been diagnosed with t-cell lymphoma….the tumor that was removed from his back was at the pet chip injection site and, once the tumor was removed, this chip was no longer there. The pathologist said the chip was attached to the tumor! Why don’t they warn people about this?? (can you say $$$?) I realize that the chip has saved countless animals and returned them home, just seems to me that pet owners should be forewarned that this might happen and that they should be hyper-vigilant to any changes in the skin around the injection site.
    Prognosis? 10 – 12 months, not the 12 – 15 years he should have had…we are just heartbroken over this! Pet owners BEWARE!

  12. Good article, great comment. You may want to read an article just published by WorldNetDaily on dog microchips. It tells the story of two dog owners, whose dogs developed a malignant microchip induced cancers. The article can be found at http://www.wnd.com/index.php?fa=PAGE.view&pageId=131533

    Katherine Albrecht, the anti-chip advocate urges all pet-owner whose pets suffered from bad microchip reactions to contact her and help her get the word to other pet owners.

    If you pet has suffered from a microchip, please share your story with Katherine Albrecht in order to educate other pet owners on the negative effects of the microchips.

  13. Twang Aguilar says:

    I am so grateful for this site & everyone’s comments. I just got a mini poodle & deciding whether or not to have microchipped. Well the slightest chance of causing him cancer is not worth it. I rather put a name tag & be extremely careful not yo loose him. Thank you all!

  14. Linda Riles says:

    I am wondering if micro-chipping could be the cause of symptoms of pano. My dog now has two microchips – a US and a Canadian chip. The US chip was supposed to be able to be universally read, but the CKC couldn’t recognize it and she had to have a second chip that the CKC would recognize to get CKC registered. Since my dog was 7 months old (she is now two)she has suffered from inflammation in her shoulders and is lame off and on. How likely is it that the problem could be the chips? The dog is from a very well respected breeder.


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