Do microchips cause cancer?
Last fall, stories such as this one in the Washington Post made headlines by announcing a link between implanted microchips and cancer. The microchips in the story are similar to the ones that commonly are used to reunite people and lost pets.
From the story in the Post:
A series of veterinary and toxicology studies, dating to the mid-1990s, stated that chip implants had “induced” malignant tumors in some lab mice and rats.
Since biological processes in mice and rats are similar to those in cats and dogs, this raises an obvious question. Could the millions of microchips that have been implanted into pets put them at risk of cancer?
Microchips have been used extensively in pets over the last decade. They are especially prevalent in the United Kingdom, where over four million cats and dogs have received the implants. The British Small Animal Veterinary Association has been tracking adverse reactions to microchips since 1996. They identified a link between microchips and cancer in two dogs.
Two dogs out of four million is a very low number indeed. Based on the available information, it appears that microchips cause cancer in dogs and cats at a negligible rate.
Also, it turns out that the strains of mice and rats cited in the studies that first noted the microchip-cancer link had been developed to be especially prone to cancer. In these animals, microchips caused tumors at very high rates. So did anything else that was implanted under the skin. In this case, it may not be appropriate to draw a direct link between these rodents and household pets.
I am not saying that microchips are risk-free. The site of implantation may become swollen or infected. The chip may fail.
However, the likelihood of such adverse events is low. Like so many things in medicine, the risks of microchipping your pet must be weighed against the benefits. To speak from my personal experience: I have never seen a pet suffer an adverse consequence from a microchip. However, microchips have helped me return several pets to people who were looking for them.
In my opinion, the benefits of microchips outweigh the risks.
If you want to read more (much, much more) about the risks and benefits of microchipping pets, click here.
You have questions. 
I’ve never been a fan of microchips. Had 2 of my friends that had terrible experiences with their dogs. I rather use a good pet tag like returnmoi pet tags or usb tags than microchips.
At our clinic too, we’ve reunited many pets with their owners–including a few repeat offenders. ; )
Having had a friend who is a breeder nearly lose one of her dogs due to a migrating microchip (plus a very expensive account for its surgical removal and further associated medical treatment of her dog) I wonder if the benefits really outweigh the risks of microchipping. This particular friend after her experience with her dog had her entire kennel scanned to locate every microchip and discovered that most of them had migrated, which prompted her to have them all removed at great expense.
It is interesting that the link that accompanies this article states that migration is the greatest malfunction in the test group of animals.
How many of us after our dogs are microchipped have them scanned at a later date to see if the microchip is still where it should be?
In the case of my friend’s seriously ill dog where the microchip was travelling to her dogs heart and she was told would have caused it’s death, most of her other dogs had theirs located in their front legs.
While the benefits of microchipping are promoted as being reuniting lost dogs with their owners, the article attached on the link to this article states that all dogs should still have other forms of identification on them. Why if it’s such a great form of identification?