Lung Cancer in Nonsmokers

Although people may tire of hearing me preach anti-smoking sermons, I rarely tire of warning them about the health dangers of tobacco. For those who smoke, quitting remains the most important positive step someone can take to reduce her risk of cancer, heart disease, and many other smoking-related diseases. Never starting to smoke is the smartest investment a young person may make in her future health. I practice what I preach, too. My parents reared me in a smoke-free environment. Temptations to smoke never assailed me. My house is a no-smoking zone. To borrow from the old liquor temperance standard, the lips that touch tobacco shall never touch mine.

And yet, I can still get lung cancer.

While tobacco exposure, chiefly in the form of cigarette smoking, is by far the greatest risk factor for lung cancer development, about 10 percent of all persons in the US who develop lung cancer have never smoked. What’s going on?

The American Cancer Society (ACS) estimates around 7000 deaths from lung cancer each year are linked to secondhand smoke exposure. Now that restaurants, entertainment venues, and workplaces are largely smoke-free environments, this exposure occurs principally in the home. If not for their own sake, then, active smokers should quit for the benefit of others with whom they live.

Uranium, which we normally associate with nuclear power plants and atomic bombs, occurs naturally in the soil in small concentrations. As a uranium atom decays, it emits radon, which forms a gas at room temperature. In the outdoors, radon quickly disseminates, but in closed environments, such as houses with basements, the gas may concentrate sufficiently to produce radiation damage to cellular DNA when inhaled. This mutation enhancement can lead to cancer development. Every house should have a radon detector.

Air pollution used to be a lung cancer risk factor in Americans. Happily, the air quality in this country improved enormously over the past half-century. In many other countries, however, pollution is a growing problem. Expect to hear of rising lung cancer incidence in those parts of the world.

Industrial and work-place exposures to certain irritants, many of which act in synchrony with tobacco smoking, have in the past contributed greatly to increased lung cancer risk. Most people know about the dangers of asbestos. I’ve already mentioned uranium. Coal miners, sand blasters, and persons working in the petroleum industries receive exposure to cancer-promoting substances. Improved workplace conditions in America have lowered cancer incidence but the problem is not yet eradicated.

Finally, the ACS lists what I must call dumb “luck,” the acquisition through the normal, fallible process of cellular reproduction of unfortunate mutations promoting cancer development. No guards against this exist. Sometimes in an imperfect world the body makes unforced errors. But it helps to minimize the risk factors you can control.

The take-home message from the sermon remains: Don’t smoke and quit immediately if you do. That doesn’t mean the nonsmokers may relax their vigilance.