With today's press release from the International Agency for Research on Cancer-commonly known as IARC-the cell phone controversy is certain to heat up once again.

Unfortunately, drawing broad and sweeping conclusions based on a press release and a news conference leaves many of us wondering just what the evidence shows that led to the conclusion announced today that "radiofrequency electromagnetic fields" may be possibly cause cancer in people. 

The quick translation of "radiofrequency electromagnetic fields"-or RMF-is huge, since this announcement is focused on the use of cell phones, which have been in widespread use by millions around the world for years.

So it is important to dissect the IARC statement for what it says-and what it doesn't say-and then try to interpret that information as it applies to our everyday lives.

First, a couple of key points:

• 1) IARC is highly regarded, especially in the area of human carcinogens (substances that cause cancer). For example, the American Cancer Society relies on IARC as a reputable resource to help answer the questions of what substances cause cancer in humans, may cause cancer in humans, or do not cause cancer in humans.

• 2) It is very treacherous to draw conclusions from press releases, whether they are from IARC or other sources. There is science behind the press release, but that science remains unknown to the rest of us until the actual research is published. In this case, IARC tells us a paper will be published "in a few days online" in the journal The Lancet Oncology. In addition, the references on which the IARC committee based its conclusion for the most part remain "in press," which in simple terms means they have not yet been released for widespread review and comment.

• 3) Deciding whether or not cell phones increase the risk of cancer in humans no easy task. This question has been a topic of intense discussion for a number of years. There are many experts on either side of the question, and there are others who sit in between, awaiting definitive evidence that cell phones do or do not cause cancer. The American Cancer Society has several pages of information on its website discussing the risks of cell phones, including a summary of information from several government agencies.

Why has it been so difficult to answer the question about cell-phone use and cancer? 

It turns out that the simple answer is that the research hasn't clearly pointed in one direction of another.  In addition, there are so many variables that can confound these types of studies such that a clear conclusion isn't evident.  So we end up in a quagmire of scientific opinion instead of the crystal clear direction we would prefer.

Putting the IARC statement into perspective does take some parsing of words to understand completely.

First, the conclusion itself:

"The evidence was reviewed critically, and overall evaluated as being limited among users of wireless telephones for glioma and acoustic neuroma, and inadequate to draw conclusions for other types of cancers.

"Dr. Jonathan Samet (University of Southern California, USA), overall Chairman of the Working Group, indicated that 'the evidence, while still accumulating, is strong enough to support a conclusion and the 2B classification.  The conclusion means that there could be some risk, and therefore we need to keep a close watch for a link between cell phones and cancer risk.'"

The press release goes on to say that the experts reviewed "hundreds of scientific articles," and that some of the research was based on papers that had been accepted for publication but had not yet been actually published in the scientific literature.

So what does "limited" mean (or in IARC language, a classification of "2B")?

The definition of 2B is provided in the press release as "Limited evidence of carcinogenicity: A positive association has been observed between exposure to the agent and cancer for which a causal interpretation is considered by the Working Group to be credible, but chance, bias or confounding could not be ruled out with reasonable confidence."

In other words, it may be true, or it may not be true.  We think it may be true, but we aren't certain. (I am not trying to be "cute" about the language used by the outstanding experts on this workgroup, merely trying to put their phrases into words that many people would understand.)

Many common exposures are classified in Category 2b, including gasoline exhaust and even coffee.

None of this diminishes the concern that we all have when we read that something may cause cancer.  The problem is heightened by the fact that we don't have the evidence we need to draw a firm conclusion one way or the other.  We are left in a place that is not comfortable, namely do we use cell phones or don't we?

I went back to a blog I previously wrote in July of 2008 to see what I said then and whether today's news would change my advice.   In the end, I thought what I said then was still relevant today:

"That leaves us in a situation where each person has to make their own decision, and weigh the benefits and risks of using a cell phone or a cordless phone.  If you feel the potential risk outweighs the benefit, you take certain actions.  On the other hand, if you are of the opinion that the absence of strong scientific evidence on the harms of cell phone use is reassuring, you take different actions.

"Finally, there are things you can do to reduce your risk, such as using newer digital models which emit less radiation.  You can limit your child's use of cell phones or encourage text messaging (which is basically the only way some children currently use their cell phones anyway.)  Finally, you can use a headset, which is what I do and have been doing for many years simply because I find it difficult to constantly hold a cell phone to my head."

That strikes me as a common sense approach to issues where we don't have convincing evidence one way or the other: if you are concerned, then act accordingly.  And if you are not overwhelmed by the evidence, then be aware of the potential risk and make your choices (and some would say, take your chances).

For me (and I suspect many others), 2B raises the bar but doesn't close the door.  There is still a need to look carefully at the actual scientific report from the committee and the additional papers cited by the committee once they are published. 

And, as always, the scientific community needs time to review all of this information, debate the issue and see how experts inform their own opinions, especially as to whether this new classification warrants a change in behavior or simply restates the obvious that there may be a problem but the evidence needs to be better developed before jumping to a conclusion.

Until we have access to the formal scientific report of the committee, we are left in a void that is awaiting the substance of their findings.

Not that that is a desirable place to be, but science doesn't always accommodate us by making us comfortable.