Pet ID Chips: A good idea?
Experts say benefits of implanted devices outweigh risks
A recent news report linking microchip identification implants to cancerous tumors has so worried some Marin County pet owners that they have inquired about surgically removing the tiny radio devices from their dogs and cats. But veterinarians and animal advocates downplay potential risks as infinitesimal.
"With the thousands of animals we've chipped, we've never been told of a tumor arising from it," said Sheri Cardo, spokesperson for the Marin Humane Society. "The risk of getting lost and dying in a shelter is much greater by far than getting a tumor from a microchip implantation."
"There are people calling veterinarians to take them out. To me, that's a travesty," said Dr. Lawrence McGill, a Salt Lake City veterinary pathologist who has studied a more defined connection between tumors and vaccines in cats.
"Microchips do a whole lot more good than they ever do harm." Since the early 1990s, millions of pets have had glass-encased identification chips the size of a grain of rice implanted between their shoulder blades. An estimated 8,000 to 10,000 lost pets--some that might otherwise be euthanized--are reunited with their guardians every month as a result of the radio frequency identification devices, or RFIDs. They work like FasTrak transponders used to pay bridge tolls, emitting radio frequency signals that transmit identification numbers through scanners or readers.
In 2004, the Food and Drug Administration approved microchips for human use, sending chills down the spines of privacy advocates who see the devices as one Orwellian step too close to the dystopian world of 1984. Also in 2004, a 9-year-old French bulldog named Leon developed a tumor next to the site of a recently implanted identification chip. A Canadian veterinarian removed the cancerous growth, and Leon's owner began investigating a connection between microchips and tumors.
In the wake of her beloved pet's death last year, Leon's owner teamed with Consumers Against Supermarket Privacy Invasion and Numbering or CASPIAN, a group working to combat what it calls retail-privacy invasion. Last year, Katherine Albrecht, CASPIAN's founder, discovered three studies noting cancerous tumors in laboratory animals. Albrecht sent the studies to the Associated Press, which found three additional similar mice studies.
In all six of the studies, researchers just happened to notice the tumors while investigating questions unrelated to microchips. McGill and other veterinarians said they were not particularly concerned about the findings because laboratory animals are more susceptible to tumors than dogs or cats.
"Chips do cause tumors in some rodents," McGill said. "Remember, some of these rodents are bred for cancer production. So they're going to be much more susceptible than are pets."
"It's certainly the case that mice who develop tumors at the site of implants are not a reliable measure of the risk of tumor formation in pet animals," said Dr. Chand Khanna, a practicing veterinarian and the National Cancer Institute's director of comparative oncology. "What's clear is that the risk of losing a pet is infinitely greater than having a tumor develop at the site of an implant."
"I can find no reports of chips in cats causing sarcomas. We've seen four reports in dogs, and two of those were in injection sites as well," McGill said. "We have put in about 20 million chips in pets, and we have four reported tumors."
Since 1996, the British Small Animal Veterinary Association has been tracking adverse reactions from microchips in pets throughout the United Kingdom. According to the association, veterinarians have reported two tumors. Italian researchers reported the other two tumors, one of them Leon's.
Fairfax veterinarian Dr. Aaron Wentzell said he has not seen any research to suggest discontinuing using microchips to identify pets.
"I have had a couple of phone calls from clients saying that they're concerned about tumors from microchips, and they've even asked about removing them surgically," Wentzell said. "There are risks associated with anesthesia. I think it would be a very bad idea to expose an animal to the real risk of anesthesia to avoid the hypothetical risk of the microchip and the potential for tumor formation.
"The benefits of microchips are clear, and the risks are questionable."
Just last month, Wentzell said, a Fairfax woman brought a stray cat into the Fairfax Veterinary Clinic. After waving an external scanner over the cat, the veterinarian discovered a microchip linking the pet to a South Bay family, who had been missing the cat for about six months.
Cardo said the Marin Humane Society reunited 1,092 dogs, cats and other strays with their guardians last year. About half go home because of microchips, she said.
"Believe me, we would all know if these animals were all coming up with tumors willy-nilly," Cardo said. "I don't know that that risk is any greater than feeding your dog dog food from China."
She noted that the rodent studies linking malignancies to microchips came to light only because about 2,000 identification microchips have been implanted in people. The notion that humans could be bar-coded like packages of meat in a supermarket raises the specter of Big Brother and sets off alarms.
Fearful about how RFID tags might be used on people, state Senator Joe Simitian, D-Palo Alto, has proposed legislation limiting the use of the human device called a VeriChip. Both houses of the California Legislature have approved a Simitian bill that would prohibit forcing people to have chips implanted. As of early this week, the bill remained on the governor's desk awaiting his signature.
Most of the human chips implanted to date will be used to access medical histories of people, like Alzheimer's or heart-disease patients, who may be unable to communicate during emergencies. In addition, the tags could be used to control security. Mexico's attorney general and 18 of his staff members, for example, had microchip identification tags implanted for entry to high-security areas.
Last month, AP published a widely disseminated report raising questions about the connection between microchips and cancer. The AP article says the company that manufactures the human chips, VeriChip Corp., sees a potential market of 45 million Americans for its medical-monitoring chips. The article notes that the Department of Health and Human Services oversees the FDA, and, at the time FDA approved the VeriChip, Tommy Thompson served as the department secretary.
Two weeks after VeriChip's approval took effect, the AP story says, Thompson left his Bush Cabinet post, and within five months became a board member of VeriChip Corp. and its parent company. Thompson denied playing any role in the FDA's approval of the VeriChip, and, he told AP he did not even know of VeriChip while serving as the Department of Health and Human Services secretary.
Although veterinarian pathologist McGill feels uncomfortable about industry or government being able to monitor his every move, he said he would have no problem microchipping a dog, a cat or a parent with Alzheimer's.
He advises worried pet owners to check their furry friends regularly for tumors and to have veterinarians regularly check for tumors. Also, he said he has articles coming out in two veterinary journals this month urging pet doctors to avoid vaccinating animals at microchip implant sites. McGill wonders if the combination of microchips and vaccinations in the same spot could increase the risk of tumor development. "Why stir the pot?" he asked.
Dr. Grace Bransford, a veterinarian and owner of Ross Valley Veterinary Hospital in San Anselmo, said she has never seen a microchip cause a problem.
"If Marin was to ever have a natural disaster--God forbid, like a major earthquake--then it's gonna be a great way of reuniting pets with owners," she said. "I'm a firm believer in them."
Contact Ronnie Cohen at ronniecohen@comcast.net.