Smokers face an irony in effort to trim risks

Study cites shift from one cancer to another

By John Schwartz
Washington Post

Smokers' attempts to find a safer cigarette may have led to a dramatic
shift from one kind of lung cancer to another without lowering the overall
cancer risk, new research suggests.

The rise in the use of filter cigarettes coincides with an increase in the
amount of adenocarcinoma, or cancers found at the periphery of the lungs,
the research found. Such cancers were considered rare in the 1950s but have
become the most common form of lung cancer, displacing squamous cell
carcinomas found in the central bronchi of the lungs.

For many years, researchers have attempted to explain the rise in
adenocarcinoma and have suggested that the increasing use of filters since
the 1950s produced a milder smoke that smokers could draw deeper into their
lungs.

At the same time, nicotine content has dropped from about 2.7 milligrams
per cigarette in 1955 to about 1.0 in 1993, possibly causing smokers to
compensate by puffing more aggressively and holding the smoke in their
lungs longer to squeeze the most nicotine out of every drag.

The result: those peripheral cells could receive greater exposure.

But until now, researchers have not been able to determine whether the
increase might actually be a result of improvements in cancer diagnostic
methods, which may have yielded more of the relatively hardtospot
adenocarcinomas over time.

In the new study, published in today's issue of the Journal of the National
Cancer Institute, researcher Michael Thun of the American Cancer Society
and colleagues examined Connecticut's longstanding registry of cancer
statistics and data from two American Cancer Society studies.

They found that adenocarcinoma rose 17fold in women and 10 fold in men
between 1959 and 1991, which reflected the rise in smoking filtered
cigarettes. Similar results emerged from examination of the American Cancer
Society studies.

The researchers said tobacco's changing composition could have an effect as
well. Since the 1950s, cigarette makers have relied on use of reconstituted
tobacco, made from tobacco stems and higher in nitrates, which produce some
carcinogens in smoke.

Adenocarcinoma is generally considered more readily curable than squamous
cell carcinoma if it is caught early but that kind of cancer is rarely
caught early, according to Adi F. Gazdar of the University of Texas
Southwest Medical Center.

"I'm not saying it's a good cancer to have no lung cancer is a good
cancer to have," said Gazdar, who wrote an editorial accompanying the
article. "The message is, to pretend that you can make a safer cigarette
and get away with it is stupid."

Representatives of the Tobacco Institute did not return calls seeking
comment. A researcher often recommended by the institute to journalists,
Gio Gori, called the rise in adenocarcinoma an "old story" and said the new
research is inconclusive.

Gori, a former deputy director of the National Cancer Institute who led the
federal effort to find safer cigarettes, insisted that the new report does
not mean that no cigarette can be safer: research should focus, he said, on
delivering nicotine while reducing toxic tar as much as possible.

The tobacco industry has never made explicit statements that the new
cigarettes were less dangerous a course of action that would have
brought on regulation by the Food and Drug Administration.

Instead, "the industry carefully played on the American public's belief
that light and low tar are synonyms for safer," said Matthew Myers of the
National Center for TobaccoFree Kids.

That confusion "may be the most harmful consumer fraud ever imposed upon
this nation" because it "probably caused millions to switch instead of
quit, and therefore may have actually contributed to the number of
smokingrelated deaths," he said.