Filtered Cigarettes Reduce Lung Cancer Risk

You know that cigarette smoking is the No. 1 risk factor for lung cancer (and a host of other serious diseases). However, if you do choose to smoke, you may wonder if filtered cigarettes are a safer alternative than unfiltered cigarettes. They’re not. In fact, there’s a major effort underway to convince the Food and Drug Administration to ban cigarette filters with holes in them.

In 1964, the Surgeon General’s report stated that smoking caused lung cancer. Tobacco companies were encouraged to make changes in their product to reduce damage to smokers, says Dr. James Davis, medical director at the Duke Center for Smoking Cessation.

The tar in cigarette smoke had known carcinogens (cancer causing agents), so it was a reasonable idea that reducing tar content would lower lung cancer risk. To do this, manufacturers added tiny holes in their filters. When a smoker inhales, these holes bring in outside air along with the smoke. The filters help trap tar, and the highly porous filter paper also allows toxic chemicals to escape. “If you combine air with smoke, you expect to get less smoke and less carcinogens,” Davis says.

Almost all cigarettes sold have these filters with holes, says Dr. Peter Shields, lead investigator and deputy director of The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital and Richard J. Solove Institute. “Regular cigarettes have them. Light cigarettes have them, but more. Ultra light cigarettes have them even more. [The filters] made the smoke smoother, so smokers thought [these cigarettes] were healthier.”

When scientists analyzed smoke from filtered cigarettes on a smoking machine – a device that mimics a person smoking – they did show more air and less tar. “It made sense to everyone that [the holes in filters] were helpful,” Davis says.

It turns out, however, that when scientists looked at lung cancer rates by when people were born, they found that despite an overall decrease in lung cancers, the rate of new adenocarcinomas, a certain type of lung cancer, was increasing.

“In the 60s and 70, the most common type of lung cancer was squamous cell carcinomas [which accounted for about two-thirds of cases]. Now, two-thirds of lung cancers in men are adenocarcinomas,” Shields says. Since women really started smoking en masse in the 1970s, after the implementation of filters with holes, they primarily developed adenocarcinomas lung cancers. “The evidence was absolutely clear that adenocarcinomas were going up when they shouldn’t be,” Shields says.

Cigarettes burn differently with ventilation holes, Shields says. You actually get more – not less – bad chemicals. Furthermore, because smokers are addicted to nicotine and get less of it with filtered cigarettes, they compensate by smoking more and taking bigger, deeper puffs, thus inhaling more smoke, more deeply into the far corners of the lungs where adenocarcinomas develop. Smoking machines, researchers learned, do not mimic how real people actually smoke.

According to Davis, it’s difficult to say with certainty if there’s a causal relationship between filter holes and the high rates of adenocarcinomas. “It’s hard to say one thing causes another,” he says, “but by my reading of the evidence, it’s really strong. We don’t wait to see [data showing] bold causality when we see a strong relationship that’s causing real harm. The scientific community should be concerned.”