My Dog’s Microchip May Have Given Him Cancer

Posted on March 7, 2008 by Allie



Our German Shepherd is one of the brightest spots in my life. He’s almost 100 lbs and looks a lot like a wolf, but understands the word cuddle and always tries sit in my lap. He has a favorite blanket that he drags around the house. He’s managed to win the hearts of hard core dog haters, and people who have always been utterly terrified of German Shepherds. He jumped on the mailman once, but only so he could lick his face. He herds the cat like it’s his job. He snores while I write, and it’s the best sound I can think of.

When we brought him home four years ago, he was a funny looking five month old puppy with a head he needed to grow into and legs like tree trunks. I fell in love with him immediately. I was so terrified by the idea of losing him, that I took him to the vet to get microchipped.

This February, I noticed a growth on his shoulder. We took him to the vet and had it removed and biopsied. Two weeks later, the biopsy came back and we learned that he had squamous cell carcinoma, a locally aggressive cancer not normally found in that location, or in a dog so young. At our vet’s suggestion, we took him to a veterinary oncology specialist. They did a series of tests and recommended that we have more tissue removed from his shoulder to get wider margins on the tumor site.He had the surgery on Wednesday. According to the surgical report his microchip “was found in the tumor-contaminated surgical field.” I asked his surgeon if she thought the microchip caused the cancer. She said she didn’t know absolutely, but if it was a coincidence, it was an awfully big one, (especially since his tumor was in such an odd location and rare in a dog his age).

I’m not sharing any of this to incite fear. I’m not saying you should have your pet’s chip removed if they have one. Or not get your dog chipped if they are prone to running away. But had I known there was any risk involved with getting my dog microchipped, I wouldn’t have done it. I would have weighed the risks and benefits and I’d have realized that it didn’t make sense for him. My dog is never alone outside. We don’t leave him in a fenced in yard where he could escape. He doesn’t take off after squirrels when we take him hiking (the bunnies in our yard don’t even bother to run away from him anymore). And he’s way too codependent to let me out of his sight.

I read all of those “news” stories about cats accidentally stowed in a suitcase, or a shipping box, traveling across the country, but being reunited with their owners because they had a microchip, and I wanted that security of knowing that I did everything I could to keep my dog safe. Unfortunately, what I did in an effort to keep him safe is the likely cause of his cancer. Had we gotten our dog this year, instead of four years ago, this wouldn’t have happened. Four years ago, I thought any product sold in my vet’s office had to be safe.

The research I do for this website has opened my eyes to how important it is to be your own health advocate. We can’t trust that companies hold our health and safety, or the health and safety of our pets, as a top priority (think pet food recalls). We can do everything right and still not have control of every outcome, but I’ve learned how important it is make well-informed decisions. Our dog’s prognosis is open at the moment. He came home yesterday. Aside from tiring easily and having an enormous scar, he’s back to his goofy old self. We’ll get his new biopsy results in 10 to 14 days. The wait seems long and torturous, but I’m trying to focus on just spending time with him and figuring out the best way to cuddle without getting a split lip from his giant plastic e-collar. He’s already figured out how to drag his blanket around with the collar on.


  1. My favorite part of this post is the last line:) I’m so glad that you are sharing this information with everyone. I hope you are cuddling with Argo right now!

    March 7th, 2008 at 7:20 pm
    Comment by Corinne Bowen
  2. I hope he’s ok. I’m definitely going to think twice about getting my dog microchipped.

    March 7th, 2008 at 9:37 pm
    Comment by The Modern Gal
  3. Aw, I’m sorry Allie — I hope he’s better really soon. Thanks for telling the internets about your experience, people need to know these things!

    March 7th, 2008 at 9:47 pm
    Comment by Amanda
  4. I’m so sorry to hear your friend is sick. While I have too many cats to seriously think about getting a dog at the moment, I love German Shepherds. (My Grandma had one when I was little and he was a great friend to me during some tough times.) I hope everything turns out okay.

    March 8th, 2008 at 8:18 am
    Comment by Susan
  5. Thank you so much for all of your support! I really appreciate it.

    I’ll keep you updated about his test results.

    March 8th, 2008 at 1:20 pm
    Comment by Allie
  6. I’m so sorry about your dog – he looks gorgeous. I love German Shepherd dogs.

    I always felt guilty about my cat. I always had her vaccinated against the usual cat diseases to keep her well and so I could board her at a cattery if I needed to do so. But she died aged 10 and I read afterwards that having cats vaccinated often shortens their lives. I have no idea if this is true but I felt very bad about it. Like you say, if I had known I could have made an informed choice.

    I hope your dog makes a good recovery. His youth should stand him in good stead.

    March 8th, 2008 at 5:27 pm
    Comment by Reluctant Blogger
  7. I hope your pup has a speedy recovery. I’m so sorry this happened to you. I hope the new biopsy comes out cancer free.

    I just brought home a puppy of my own 2 weeks ago and was going to take her to get microchipped. This makes me question doing so. It’s very scary.

    March 9th, 2008 at 1:31 am
    Comment by Jamie
  8. You describe your dog’s lovely personality so well that I felt truly sorry to hear that he is sick. We have a shepherd/lab mix named Jade who looks quite a bit like him.

    March 9th, 2008 at 4:12 pm
    Comment by patry
  9. I was wondering what microchip brand you got for him? There is two that I know of so, do you remember if it was home again or avid?

    March 10th, 2008 at 10:58 am
    Comment by Valerie
  10. Hi Valerie — it was a Home Again chip.

    Reluctant Blogger — thank you! I’m so sorry about your cat!
    Jamie, Patry — thank you so much!

    March 10th, 2008 at 12:42 pm
    Comment by Allie
  11. Geez, I hate that even when you feel like you are making the “responsible” decisions you might be harming your animals. Wishing your pup a speedy recovery! At least he has his blanky :)

    March 10th, 2008 at 3:57 pm
    Comment by nicole
  12. Thanks, Nicole. That is the kicker in all of this. I really thought I was doing what was best for him.

    March 10th, 2008 at 5:01 pm
    Comment by Allie
  13. Hi Allie- I know how special pets are and I am sending my best wishes for your dog. They truly are our angels here on Earth.

    March 11th, 2008 at 12:58 am
    Comment by Beth
  14. I have three cats and although i have not gotten them a microchip, i have always thought about it. It would absolutely break my heart, to know that if i had gotten them chipped, that maybe they would contract a serious illness.

    I feel for you, and i hope your doggie is/gets better. It’s also good you took him to the vet right away, sometimes timing is a big factor with certain conditions. You’re a great dog mommie.

    March 11th, 2008 at 4:40 pm
    Comment by Missy
  15. Thank you so much Beth. I appreciate the good thoughts!

    Missy, thanks! Timing is a big factor. It’s a good thing he’s such a cuddly dog — I noticed the bump while I was petting him.

    March 11th, 2008 at 9:10 pm
    Comment by Allie
  16. [...] (shown with cat to illustrate scale). Now, before you worry, this has nothing to do with his recent cancer. This happens twice a year, every year, and it’s just par for the course when you have a 95lb [...]

    May 2nd, 2008 at 1:08 pm
    Pingback by Allie’s Answers » Blog Archive » Tip of the Day - Reusing Pet Hair
  17. I was seriously thinking of getting my Rottie/German Shephard microchipped, but your situation has made me think again! Reading what happened to Argo brought a tear to my eye! I hope the test results bring good news for you and Argo x x

    June 6th, 2008 at 9:47 am
    Comment by Sukh
  18. Sorry to hear your dog has problems, but I seriously doubt that the chip has caused it. I firmly believe that it is an unfortunate circumstance and my very 1st dog had cancer in the very place, long before microchips where even around. It’s very much like us two legged animals, it can strike anytime anywhere. Did you know cancer in dogs is quite common? hard to believe but true, dogs like the rest of us are living longer and of course the longer you live the greater the odds. A bit like chicken pox becoming shingles when older, when it’s the same virus!
    Cancer is a fact of life, but like us in humans most it treatable. I hope Atgo makes a speedy recovery.

    November 16th, 2008 at 2:51 am
    Comment by suzanne
  19. I, of course, know that cancer is common in dogs. I’ve done extensive research on the subject since Argo’s diagnosis. My dog was only 4 when this happened, so it wasn’t a matter of just living long enough for cancer to develop (and I actually read recently that the introduction of commercial dog food has possibly shortened the lifespan of dogs). Much like in humans, outside factors play a major role in canine cancer. Think about how smoking, chemical exposures, obesity, diet, and environmental factors play a major role in human cancer. It’s the same for dogs. And since the vets at one of the best major veterinary centers in the country seemed to think the chip/tumor relation was more than coincidence, I think I’ll stick with my theory.

    As for your first dog, I’m so sorry you lost him/her. Since pet vaccinations can also be a factor in cancer development, I wonder if perhaps that would explain the location of the tumor in your dog. But while we can’t very well stop vaccinating our dogs against things like rabies and distemper, a microchip is completely optional. I’ll be passing on using chips in the future. I understand that they have a place, but for me, personally, it isn’t worth the risk.

    If you’re interesting in learned more about preventing cancer in dogs, is a wonderful resource. Obviously, we don’t have total control of what causes cancer, but learning more about good food and other healthy habits for our pets can certainly help prevent it.

    November 16th, 2008 at 2:22 pm
    Comment by Allie
  20. My dog Dino had a tumor removed yesterday. It was behind his neck almost between his shoulder bones. His Home Again Microchip was inside. I noticed the lump about 3 to 4 weeks ago.

    Did your vet send the chip back to Home Alone so they could check it for defects? My vet called Home Alone today and a case worker to her to send the chip and copies of all the registration information so they could evaluate it and see if it was the cause of Dino’s problem. We are now waiting for the test results to come back. Due to the holidays we will not probably get it back until Monday.

    It is hard finding information on the chip and cancer. Do you have any websites to search?

    I hope your baby boy is doing fine.


    November 27th, 2008 at 12:50 am
    Comment by Lisa
  21. I am soo sorry to hear that.
    I’m planning on getting a dog and i was going to have her microchipped but because of this, I thank you so much.

    I’m so sorry, I feel your dog feels better he looks so beautiful I love your German shepherd.

    January 27th, 2009 at 9:08 pm
    Comment by Jenny
  22. I am sorry for your loss. I went in to adopt an adult cat at a shelter today and was told I had to have it microchipped if I wanted to adopt it. No choice in the matter. I walked out without a cat.

    It almost seems no one questions putting a foreign body inside a living thing and what harm it may cause. I don’t understand why so many people think this is OK.

    February 18th, 2009 at 3:11 am
    Comment by Tammy
  23. [...] When we come home, I wash Argo and Stella’s feet.  But I worry that it’s not getting all the chemicals off, or perhaps dissolving them into their skin and making it worse.  I picture chemicals seeping in to the little cracks and crevices in Argo’s worn footpads.  Maybe that’s crazy, but Argo has already had cancer once. [...]

    August 6th, 2009 at 4:55 pm
    Pingback by Lawn Chemicals, Cancer, and Dog Boots
  24. I am wary of microchips as well. We recently lost our two-year-old Lab to Osteosarcoma. He went from having a small lump on his side to a huge lump and cancer that had spread throughout his whole body in just six short weeks. He was in such pain we had to euthanize him. He is the only dog I have ever had microchipped and maybe it was just a freak thing he developed cancer but I can’t help but point my finger to the chip since that is the only thing different from how we raised and treated our other dogs.

    August 10th, 2009 at 12:57 am
    Comment by Kim
  25. My aunt has a huge lab/shep mix, by the name of Boomber, and he’s even younger.. And just had a cancerous tumor removed in nearly the exact same spot. Thankfully they caught it in time, but it gave us a scare. However, he IS NOT chipped, so, no such instance here.

    I actually work for one of the bigger chip companies.. (I’m obviously not saying here because I would like to keep my job.) However, the chances of cancer being caused by microchips are very slim, however, any foreign object insert into a body may cause reactions, it’s up to the pet owner to make that choice if it’s worth it or not.. I’m not saying this because I want people to keep getting chips done or not.. I’m saying because it’s something I elected to do for my two indoor cats, and back when my old dog was around, if I could have afforded it (being a kid means no income!), she WOULD have been chipped, as a beagle mix means she got away every chance she got!!!!

    Anyway… The chances of your pet developing cancer because of a microchip versus being put down at a shelter because the shelter can’t find you because your pet ISN’T chipped is like the chances of getting struck by lightning versus getting into a car accident. Obviously, choice B is far more common.. Which is why chips are so important and have saved millions of pets’ lives by now.

    Either way, the choice should be up to you, the owners. No matter what, make an INFORMED decision.. However, keep in mind if you own a purebred dog, or a small dog (Yorkies, Chihuahuas, etc), I personally highly advise getting them chipped- these dogs, along with bigger dogs like Pitbulls, Labs, and Huskies, get stolen all the time, and that chip could be what proves the pet is yours and gets it back to you.

    September 13th, 2009 at 9:25 am
    Comment by just a girl
  26. [...] with cat to illustrate scale). Now, before you worry, this has nothing to do with his bout with cancer. This happens twice a year, every year, and it’s just par for the course when you have a 95lb [...]

    November 11th, 2009 at 9:18 am
    Pingback by Reuse Pet Hair
  27. Hi Allie,thank you for your share and thought. I live in Indonesia, and no report for this case of microchip. Im wondering, what type of microchip you use? metal or plastics? and im wondering, which site of rabies vaccination site of injection of your dog? because, from i read, rabies site of injection could developed cancer also. Thank you..

    December 3rd, 2009 at 1:25 am
    Comment by eka
  28. I am hearing from friends who are vets reports that microchips MAY present a risk but it’s too soon to tell. However the info I get from friends who are vets is microchips are not universally read- not to mention some chips can be read at some shelters and not others. Some shelters can’t read them at all. The BEST and safest option is to have your pet tatooed either on the belly when it’s being spayed/neutered or if that’s been done already, get it done on the inside of the ear. I have tried to take the chip out of my dog that has been rescued from a shelter. Sadly it’s in her muscle and can’t be removed without damage to the muscle.

    March 12th, 2010 at 1:10 am
    Comment by
  29. We also have a microchipped German Shepard Dog who has had 3 small skin tumors on her shoulders and hips. I plan to show your article to our vet to see what she thinks. Our dog is recycled, too. She was trained as a wheelchair helper dog, but she growls at strangers and chases squirrels, so she ended up as a pet. Thanks!

    March 17th, 2010 at 8:34 am
    Comment by Jim F
  30. 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

    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.

    March 25th, 2010 at 11:04 pm
    Comment by Lydia
  31. Our 5 year old Yorkie has cancer, the tumor that was removed from between his shoulders was attached to another tumor that had the microchiip inside! I’ve talked to several other pet owners that have experienced the same thing with the microchip and the tumos all had the chip inside! This is not a coincidence but is the best kept secret in the pet world! AND, all chip makers use a differennt frequency for their chips so, if you don’t have the correct scanner, you won’t read the chip!

    April 13th, 2010 at 12:10 pm
    Comment by Linda Hawkins
  32. Thank you for sharing your story. Unfortunately, those promoting microchip implants are not warning the public of potential adverse reactions associated with microchip implants. Instead, the chips are promoted as “safe” and “life-saving” devices. However, there are serious potential adverse reactions associated with microchip implants.

    For scientific reports that clearly demonstrate that microchip implants have resulted in tumors, neurological damage, and death, visit:

    It is also important to realize that microchip scanners cannot read all microchip implants all of the time. A document published in JAVMA even says, “None of the scanners examined had 100% sensitivity for any of the microchip brands. In addition, there were clear differences among scanners in regard to sensitivity.” ( ) This means that your animal may be scanned for a chip but the scanner may not be able to read it. This is what happened to a dog named Hadden. Sadly, Hadden was euthanized because the shelter’s scanner could not read his chip. Here is Hadden’s story:

    April 14th, 2010 at 10:25 am
    Comment by Mary Jane
  33. One of our dogs is an eight year old Japanese Chin female (spayed). Not very long ago, I decided to have her microchipped. I thought I was doing the right thing. She was diagnosed with a bad vertebra in her back years ago. When she stopped wanting to climb stairs, I thought her back might be getting worse, so I took her to a well known vet teaching hospital to have an orthopedic specialist do and x-ray. Long story short, she didn’t get the x-ray. They decided since her eye “menace” didn’t respond quickly enough (she has short optic nerves), she always circles to the left, and she doesn’t right her feet immediately when knuckled, that she has an intracranial lesion. When I took Matti over there, the ONLY concern was that she didn’t want to climb stairs. At 7 lbs, I certainly didn’t mind carrying her, but wanted to make sure nothing was wrong. They took her out of the room two times during the exam. I’m not trying to say they did anything wrong, but she was so stressed out by the time they were done, that I thought she was going to have a heart attack. Don’t get me wrong, she’s never been crazy about going to the vet, but NEVER like this. They want me to take her to Missouri or Chicago for an MRI. I took her home and I have been physically sick ever since. Last Friday night, she started having seizures and had six in a 21 hour period. They have started her on Phenobarbital. I went from a dog that ran and played, but just didn’t want to climb steps, to a dog that didn’t want to do anything and is in pain. Now I read about the microchips possibly causing cancer. When Matti got her microchip, it seemed to hurt her a lot. In fact, she tried to swing around to bite the vet, and she is an extremely docile dog and would never do that. I regretted getting it right then. Now I’m wondering if the microchip is the root of her problem. I already feel guilty about taking her to a “specialist” and coming back with a dog in pain. Now I’m learning that I might have given her a tumor by inserting what I thought would save my dog if she got lost. No one has wanted to do blood work on her. They just wrote her off as having a brain tumor. I called the vet and insisted I wanted a full panel blood work up before we do anything else. She has an underactive Thyroid and has always had an elevated liver count, so the Phenobarbital concerns me. I am going to ask if an x-ray would show if there is a problem with the microchip, but it might take a CT or MRI. So I can’t get this piece of junk out of my dogs (we have ten and six of them are microchipped) without injuring tissue? I will guarantee you the other four will not be microchipped.

    May 4th, 2010 at 6:20 pm
    Comment by Kathy Pierce
  34. Update on Matti: No one really wanted to do a full blood panel on Matti, so my husband and I just decided to go ahead and schedule a fasting major panel anyway. She goes tomorrow to our regular vet for blood work and x-rays. The x-rays will also show if the microchip has moved. If this doesn’t show anything, I have her scheduled at the University of Missouri Tuesday morning for an MRI and whatever else is needed. Matti is eight years old and some people might think we’re crazy, but we went from a dog that was seemingly healthy to a dog that seriously sick…all in one day’s time. I HAVE to know what is wrong with her. Even if it’s something we can treat or can’t afford to treat,at least we might know what happened. This Phenobarbital is making her so wobbly she can hardly stand. That’s not living for her. I cut the pill back a little today just to see if it will not “drug her up” quite so much, but still keep the seizures away. I’m home from work today because I was worried about her condition last night, so I thought I’d better stay with her today. I’ll update you on what happens Friday. Allie: Thank you so much for the email. It helps to “talk” to someone who has been through similar problems.

    May 6th, 2010 at 11:00 am
    Comment by Kathy Pierce
  35. Sorry. I haven’t had a lot of sleep the past week. What I meant to say was………even if it’s something we CAN’T treat or can’t afford to treat….

    May 6th, 2010 at 11:03 am
    Comment by Kathy Pierce
  36. I can’t see the image, but I wanted to say I’m sorry you’ve lost your friend. I know this sounds corny, but she’ll always live in your heart. That’s how I feel about my mom.

    September 27th, 2010 at 2:20 pm
    Comment by Lesley Appell
  37. While I understand your concern about the microchip to seemingly be a cause of the cancer, and it is indeed coincidental, I have see so many dogs and cats with cancerous tumors in every imaginable location, based on the research and statistics I find it nearly impossible for this to have been the cause of the cancer. I also just reviewed the “.. scientific reports that clearly demonstrate that microchip implants have resulted in tumors, neurological damage, and death” at” from the comment submitted by MARY JANE and find that her conclusions are not at all what the reports state.

    You can read these research articles yourself, but here is just one of the conclusions:

    “In this case, it is difficult to establish which was the primary cause of the neoplastic growth, because the dog had received several rabies vaccines and the microchip was detected close to but not included in the mass. A concause could then be hypothesized. Notwithstanding, reports on adverse reactions to vaccination and microchips are strongly encouraged to deepen the current knowledge on their possible role in tumorigenesis. In fact, the cause-and-effect relation between exposure (injection) and the outcome (sarcoma) is still to be defined and is a matter of discussion for experts.”

    See, no conclusive evidence, only conjecture – and always mitigating circumstances. I submit that with tens of millions of pets having been microchipped and only a very few reports of cancer remotely being the possible cause,it makes much less sense to risk losing an animal to the street, a stranger or being euthanized because the owner can’t be located.

    Pets; dogs and cats are lost at the extremely – and ridiculously – high rate of over 15% of all household pets! It makes much more sense to get your pet microchipped. Statistics show that it will save their lives at exponential factors compared to the possibility of contracting a cancer from the chip.

    September 30th, 2010 at 5:20 pm
    Comment by Arny Mickle
  38. I would be very interested in speaking to Allie who posted Argo’s microchip experience, Lisa with Dino, and Kathy Pierce with Matti to find out more about these cases – specificalkly if the chips were proven to have caused the cancer.
    If anyone else has experienced an adverse reaction to a microchip, suspected or otherwise, in their pet (cat, dog or horse) I would also be interested in speaking to them also.
    I have been looking into and writing about possible side effects of microchips for two years now, and any further information would be gratefully received. Please email with any info.
    Thank you,
    Caroline Davis.

    June 21st, 2011 at 5:26 am
    Comment by caroline davis
  39. Go to a Health Food Store and buy the excellent book “Natural Health for Dogs and Cats” written by Veterinarian Pritcairn. Price is about $15. Any animal lover should have this book.

    August 16th, 2011 at 6:13 pm
    Comment by dora
  40. My 11 year old cat who was microchipped 8 years ago just had surgery yesterday to remove a suspicious lump between his shoulder blades. It was the microchip! It had formed a large (2 1/2 inches) cyst around it. We are awaiting toxicology reports….

    September 17th, 2011 at 11:12 am
    Comment by Amy
  41. I have 5 cats and a 7-yr old German Shep I adopted 2 yrs ago. With each adoption, I was asked if I wanted to micro-chip. Every vet I speak to says it should be safe but these days it’s hard to get a straight answer out of them. The thought of forcing any foreign-object underneath the skin of my pets just did not sit right with me. After reading your article and the other comments, I am glad I did not. Thanks for sharing everyone! As the TV commercial says, “…The more you know…”

    February 9th, 2012 at 1:51 pm
    Comment by Lee
  42. Hi Allie,

    I read your article as my beagle has been diagnosed with lymphoma two years after a microchip implant. He has a big lump on his shoulder probably right where the microchip is. Before this he was a very healthy well fed dog, all freshly prepared food. In Australia we don’t have a choice I was forced to chip him and the vet now says he has 3 months to live. It breaks my heart to see him suffer and I feel very sad and angry that I was forced to do this, as I would never have chosen to risk his health. Sue

    December 31st, 2017 at 11:26 pm
    Comment by Sue

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