Microchips and Cancer

By Jean Hofve, DVM

I’ve been seeing some articles about the “dangers” of microchips and the potential for cancer.

There are several things you need to know, in order to assess this information:

1. The strain of mice used in these experiments are bred to be especially susceptible to tumor formation. The fact that these particular hypersensitive mice develop tumors is not applicable to cats or dogs.

2. Any injection, bruise, or other trauma has the potential to cause cancer (fibrosarcoma) in cats secondary to inflammation. In one notable case, a surgical staple initiated a cancerous growth. The “killed” rabies, feline leukemia, and feline AIDS (FIV) vaccines are more commonly implicated, because they are designed to create more inflammation in the area of injection. But even giving fluids–a procedure used on thousands of cats every day–has a remote chance of triggering tumor formation. Fortunately, the risk is very slight.

3. The chances of even a strictly indoor cat getting out or lost are much, much higher than the chances of a tumor resulting from a microchip. Very few lost cats ever find their way home; but having a microchip (and hopefully additional identification like a collar) makes it much more likely you will be reunited with your cat.

4. Literally millions of dogs, cats and horses have been microchipped. In the veterinary literature I could find only ONE published report of a chip-associated tumor in a dog. The renowned pathologist at my alma mater, Colorado State University, said she had seen only one in her entire career.

5. To ensure the best results with minimal risk, I recommend that the chip should be placed slightly off the midline and away from all acupuncture meridians (particularly the bladder meridian, which runs parallel to but a small distance away from the spine), and a dose of homeopathic Ledum 30C given immediately afterward.

6. I advocate microchipping even though one of my own cats produced a spectacular sterile abscess that covered his shoulder and halfway down his leg. So I’ve seen a nearly-worst-case scenario, but I still chip.

7. Even though my (Dr. Jean’s) own cats are indoor-only and not committed door-runners, occasionally one will accidentally get outside. Fortunately I’ve caught or found them quickly with no harm done. But ALL my animals are microchipped; it’s cheap “insurance” and I wouldn’t have it any other way!



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2 comments for “Microchips and Cancer

  1. jhofve77
    June 17, 2011 at 8:09 am

    It is certainly up to the guardian to keep their info current in the microchip database! But even though one of my own cats developed a horrible abscess from a chip, I still microchip all my animals. The technology isn’t perfect, but to me it’s added insurance in case my indoor cats get out…in fact just the other day Sundance waltzed right out the back door as I was taking out the trash. Of course collars and tags are needed, but they can come off, and I’ve seen cats get their jaw or a foot stuck in the collar, not to mention collars catching on fences or trees and potentially hanging the cat. Cats should have breakaway collars, but of course those collars are easily lost. Guardians have to balance the handful of documented cases where the chip has initiated cancer against the hundreds of lost pets who have been returned to their homes, thanks to chips. I don’t worry too much about the conspiracy theories about microchipping people, of course I’m probably past the age where that future will get me! But thank you for writing and expressing your concerns–people should understand both risks and benefits before making that decision!

  2. wk
    June 16, 2011 at 10:54 pm

    I have lost 5 pets to cancer in 4 years. All but one was microchipped. I HATE the chips. Working w/rescues many chips were not registered to the correct owner. Many chips migrate. RFID companies are making a fortune pushing chips. Next will be kids and people. Not everything is as great as it appears to be. Get a good collar and tags on your pets. Best thing is not to let them out! www (dot) ChipMeNot (dot) org
    www (dot) ChipMeNot (dot)org (dot)uk



    Just like vets seem to believe CONVENIA (long acting antibiotic) is so great…it almost killed my small dog & $1400 later she made it after week in intensive care. That shot is killing a lot of cats especially.

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