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.