Thursday, November 22, 2007

Microchip Update

Last month, I wrote about a story that was broken by Associated Press reporting that implantable microchips are linked to the development of sarcomas in laboratory animals. On November 20, a group called CASPIAN (Consumers Against Supermarket Privacy Invasion and Numbering) released a comprehensive 48-page report reviewing the academic literature on this topic. They identified 11 articles related to implantable microchips. In 6 of these articles, tumors were reported in laboratory mice or rats adjacent to implanted microchips. Between 0.8% and 10.2% of the animals developed tumors, depending on the study. There were also two reports of microchip-related cancer in dogs.

In my blog entry, I suggested that one manufacturer of these chips (VeriChip) might have engaged in some less-than-honorable behavior by hiring as a board member the man who was the Secretary of the Department of Health and Human Services (HHS) at the time that these chips were being evaluated for safety. HHS directly oversees the Food and Drug Administration, the group charged with determining the safety of medical devices like these. This questionable behavior continued, as the CEO of VeriChip was quoted recently as saying that none of the tumors found in mice in a 2006 French study were malignant. This is not true – the study identified these tumors as sarcomas, and sarcomas are malignant.

In the words of the author of Cool Dog Hall of Fame, the decision to microchip pets has become much more difficult in light of these reports. Pet owners now need to weigh the risk of cancer against the benefit of potentially being reunited with a lost pet and make a tough decision. Much more research is necessary before the use of these devices in humans can be condoned. Based on the evidence available so far, Dr. Robert Benezra, head of the Cancer Biology Genetics Program at the Memorial Sloan-Kettering Cancer Center in New York, was quoted as saying, "There's no way in the world, having read this information, that I would have one of those chips implanted in my skin, or in one of my family members."


webhill said...

Some remarks:

1. Companion animal microchip safety studies have been done:

Murasugi, et al. Histological reactions to mcirochip implants in dogs. Vet rec 2003;153:328-330.
Rao, et al.

Tissue reaction to an implantable identification device in mice. Tox Path 1990;18:412-416.
Ball, et al.

Evaluation of a microchip implant system used for animal identification in rats. Lab Anim Sci 1991;41:185-186.

2. Searching PubMed for "microchips and tumours" in the time frame of 1990-2007 turns up 3 studies, which were flawed from an epidemiological perspective because p53 or 4279 CBA/J or B6C3F1 mice are genetically predisposed to cancer hence not representative of pets or even most food animals, or people for that matter, with respect to cancer incidence. Further, even in this cancer prone population, incidence was low at ~ 1%.

3. The BSAVA has a robust microchip adverse reaction surveillance system in place with only 2 reports of cancer (however, no causlaity determination) reported since 1996 for an overall incidence of 0.6%.

4. A literature search only shows 2 case reports of suspected inflammation-induced fibrosarcoma at a microchip implanation site with no definitive causality assessment.

So, given all of that, when you then look at the proven huge number of lost animals who are successfully reunited with their owners due to the microchips, I personally am hard-pressed to suggest that the hypothetical risk of cancer from the chip outweighs the proven benefit of permanent identification. I mean, I think that death rates (from euthanasia or trauma or exposure) would be higher in the population of animals who go missing with no microchip than the death rates (from chip related cancer) in the population of chipped animals. You see what I'm saying here?

Unknown said...

A pets owner have to use Animal microchip. Because every year millions of pet lost and cant come back to real owner.
Pet Microchip Reader

Anusha said...

Information like this will change the way how our system work. Radolabs Scan Centre Chennai is the leading diagnostic centres... pls do visit our labs across chennai