Highly aggressive tumors developed around the microchip implants of two American dogs, killing one of the pets and leaving the other terminally ill. Their owners — and pathology and autopsy reports — have suggested a link between the chips and the formation of the fast-growing cancers.
In the town of Paeonian Springs, Va., a five-year-old male Bullmastiff named Seamus died in February, nine months after developing a “hemangio-sarcoma” — a rare, malignant form of cancer that strikes connective tissues and can kill even humans in three to six months. The tumor appeared last May between the dog's shoulder blades where a microchip had been implanted; by September, a “large mass” had grown with the potential to spread to the lungs, liver and spleen, according a pathology report from the Blue Ridge Veterinary Clinic in Purcellville, Va.
Originally scheduled to receive just a biopsy, Seamus underwent emergency surgery. A foot-long incision was opened to extract the 4-pound-3-ounce tumor, and four drains were needed to remove fluid where the tumor had developed.
When Howard Gillis, the dog's owner, picked up his pet the following day, the attending veterinarian stunned him with this question: Did you know your dog had been microchipped twice, and that both chips were in or around the tumor?
“While we knew of one chip, which we had put in him at a free local county clinic, we knew nothing of a second chip,” Gillis said. “We believe one of them was put in Seamus by the breeder from whom we bought him when he was about nine months old.”
By December, the cancer was back — and the energetic, playful 150-pound dog was huffing and puffing, struggling to walk. Seamus “was 150 pounds of heart,” Gillis said in a recent interview. “He wanted to live.”
Gillis said he “got the microchip because I didn't want him stolen. I thought I was doing right. There were never any warnings about what a microchip could do, but I saw it first-hand. That cancer was something I could see growing every day, and I could see it taking his life … It just ate him up.” To keep his beloved dog from suffering further, he had him put to sleep two months later.
In Memphis, a five-year-old Yorkshire Terrier named Scotty was diagnosed with cancer at the Cloverleaf Animal Clinic in December. A tumor between the dog's shoulder blades — precisely where a microchip had been embedded — was described as malignant lymphoma. A tumor the size of a small balloon was removed; encased in it was a microchip.
Scotty was given no more than a year to live.
But the dog's owner, Linda Hawkins, wasn't satisfied with just a prognosis: She wanted to know whether the presence of the microchip had anything to do with Scotty's illness. Initially, her veterinarian was skeptical that a chip implant could trigger cancer; research has shown that vaccine injections in dogs and cats can lead to tumors.
In a December pathology report on Scotty, Evan D. McGee wrote: “I was previously suspicious of a prior unrelated injection site reaction” beneath the tumor. “However, it is possible that this inflammation is associated with other foreign debris, possibly from the microchip.”
Observing the glass-encapsulated tag under a microscope, he noted it was partially coated with a translucent material, normally used to keep embedded microchips from moving around the body. “This coating could be the material inciting the inflammatory response,” McGee wrote.
Hawkins sent the pathology report to HomeAgain, the national pet recovery and identification network that endorses microchipping of pets. After having a vet review the document, the company said the chip did not cause Scotty's tumor — then in January sent Hawkins a $300 check to cover her clinical expenses, no questions asked.
“I find it hard to believe that a company will just give away $300 to somebody who calls in, unless there is something bad going on,” Hawkins says.
Having spent $4,000 on medical treatment for Scotty since December, Hawkins accepted the money. But she says it hardly covers her $900 monthly outlays for chemotherapy and does little to ease her pet's suffering.
“Scotty is just a baby. He won't live the 15 years he's supposed to …I did something I thought a responsible pet owner should — microchip your pet — and to think that it killed him … It just breaks your heart.”
Scotty and Seamus aren't the only pets to have suffered adverse reactions from microchips. Published reports have detailed malignant tumors in two other chipped dogs; in one dog, the researchers said cancer appeared linked to the presence of the embedded chip; in the other, the cancer's cause was uncertain.
Last year, a Chihuahua bled to death in the arms of his distraught owners in Agua Dulce, Calif., just hours after undergoing a chipping procedure. The veterinarian who performed the chipping confirmed that dog died from blood loss associated with the microchip.
In another case, a kitten died instantly when a microchip was accidentally injected into its brain stem. And in another, a cat was paralyzed when an implant entered its spinal column. The implants have been widely reported to migrate within animals' bodies, and can cause abscesses and infection.
In 2007, The Associated Press reported on a series of veterinary and toxicology studies that found that microchip implants had “induced” malignant tumors in some lab animals. Published in veterinary and toxicology journals between 1996 and 2006, the studies found that between 1 and 10 percent of lab mice and rats injected with microchips developed malignant tumors, most of them encasing the implants.
For more information on the link between microchips and cancer, please read our report: “Microchip-Induced Tumors in Laboratory Rodents and Dogs: A Review of the Literature 1990–2006”
by Katherine Albrecht, Ed.D.