Monday, September 14, 2009

Malignant Mobiles? (Marin IJ)

Can you guess when the following passage was written: "For three decades the medical controversy over the part played by smoking in the rise of cancer of the lung has been largely kept from public notice"?

This was the lead to Roy Norr's 1952 expose, "Cancer by the Carton." For years prior to its publication, evidence that cigarettes were a health hazard had been accumulating. But, cigarettes were also a big part of American life, and when the Marlboro Man and his industry assured consumers there was nothing to worry about, they kept on smoking.

So, when do you think this label was placed on cigarette cartons: "Caution: Cigarette Smoking May be Hazardous to Your Health"?

It took 14 more years. By then, millions of Americans had developed lung cancer and heart disease. With the benefit of hindsight, we can call the cigarette story a classic, cautionary tale that demonstrates how long it takes to firmly establish and publicize a link between an environmental exposure and a disease. This is especially true when the disease is one, like cancer, that usually takes many years to develop. Hence, many public health experts preach a precautionary principle; if we think something in the environment might be dangerous, we should limit exposure.

In the last year I've diagnosed three patients with brain cancer. This, in and of itself, is unusual; brain cancer occurs in about six out of 100,000 people. But what made this particularly surprising was that these patients were all relatively young (in their 40s) and otherwise healthy. Beyond that, they shared a common habit; years of talking on cellular phones for hours a day. In one case, the patient's cellphone use was significant enough for him to ask me if I thought his phone caused his cancer. Now, I know it is dangerous to extrapolate large-scale causality from the circumstances of a handful of patients, but this cluster of diagnoses has me scratching my head.

For more than a decade, researchers have searched for a connection between electromagnetic radiation (EMR) exposure from cell phones and brain cancer. We know that low-level EMR, such as the radio frequencies emitted by cell phones, can cause headaches, auditory disturbances and short-term memory loss. EMR has also been implicated in DNA changes that may be precursors to cancer, and a recent study demonstrated that men who use cell phones more than four hours a day have significantly lower sperm quality than those who do not. As for cell phones and brain cancer, we have been awaiting the publication of what was supposed to be the definitive study - the multiyear, multinational and multimillion dollar "Interphone" study. Heavily subsidized by the telecom industry, it involves 14,000 subjects and spans 2000 to 2006. We've already had a preview of the data, without clear evidence of a cellphone-cancer link. But, before you disconnect your landline and toss it out the window, consider this:Ê

- Lennart Hardell, a Swedish researcher, has grouped the preliminary Interphone analysis with outside studies and observed a 280 percent increased risk of cancer in people using their digital cell phones for greater than an hour a day for 10 years.

- An international group of established researchers recently released a report, "Cell phones and brain tumors: 15 reasons for concern," which detailed numerous flaws with the Interphone study design, including the fact that the study did not enroll children or young adults - populations suspected to be at greater risk from radiation exposure. I asked Dr. Ronald B. Herberman, founding and long-term director of the prestigious University of Pittsburgh Cancer Institute about the report. He wrote:

"I find this critique, focused on design flaws in the Interphone study, to be well argued. I believe it will be very important for another, better-designed study to be performed. Some of the major concerns about the Interphone design could be avoided if the cellphone service providers would cooperate and provide information from their billing records about the extent of cellphone use by participants in the study. In the meanwhile, I continue to be quite concerned about the overall evidence for potential increased risk for brain tumors that has been associated with frequent use of cell phones for more than 10 years, particularly by children or young adults."

- Despite the fact that more than 80 percent of Americans own cell phones, there is no U.S. federally funded effort to study their potential health effects. This will likely be discussed at Sen. Arlen Specter's Senate hearings with cellphone researchers scheduled for this week.

So, with the results of Interphone in dispute prior to publication and with approximately 4 billion cellular phone users worldwide, including hundreds of millions of children and young adults, how concerned should we be? Concerned enough to change behavior.

Cell phones may not be physically addictive like nicotine, but for some people they are an addiction of convenience and communication. Those who spend their days with a cellphone glued to their ear or who allow their teenager to sleep with a phone under her pillow (so she can be sure to respond to any urgent midnight text messages) might want to consider the lesson of "Cancer by the Carton" - by the time we reach consensus regarding cell phones and cancer, it may be too late.

I'm limiting my own cellphone use to less than an hour a day and using text, speakerphone and landline whenever possible. When I do need to use a cellphone close to my head, I will switch to my off (left) ear or use a headset. In the future, I will only buy cell phones with low emission scores (there is wide variability in the radiation exposure from different phone models). And, most importantly, I will keep my mobile as far away as possible from my 4-year-old daughter's developing brain. By the time she asks for a cellphone of her own, I hope that high-quality, publicly funded research has settled the matter.