By Elizabeth M. Whelan, Sc.D., M.P.H., Gilbert Ross, M.D.
Posted: Friday, April 8, 2005
EDITORIAL
Publication Date: April 8, 2005
Ever since ABC News anchor Peter Jennings announced last week that he had been diagnosed with lung cancer, we have observed an increased interest in the disease--particularly the probability of it occurring in former smokers. We have spoken with dozens of former smokers and read reports of anxiety in this group, and, drawing on the American Council on Science and Health's past research, we offer facts and advice on lung cancer. Our advice is tailored to three different groups: a) ex-smokers, b) current smokers, and c) non-smokers who are candidates to take up the habit.
Risks
First, some hard facts:
--Cigarette smoke is the leading cause of preventable death in America today, accounting for at least 450,000 premature deaths.
--Approximately 160,000 cases of lung cancer are diagnosed annually in the U.S., which means that on any given day (such as the day Mr. Jennings received his diagnosis) some 460 other Americans get the same bad news.
--Just over 90% of all lung cancers are causally linked with cigarette smoking. Indeed before cigarette smoking became popular around World War I, lung cancer was an exceedingly rare disease (tobacco was used relatively safely in the form of pipes, cigars, and snuff prior to that time).
--During the 1960s nearly 70% of American men smoked, and about 50% of American women were smokers. We have dramatically reduced the prevalence of smoking in our country, with smokers giving up the habit and fewer young people taking up smoking--but the reality is that even among those who have quit, health risks associated with past smoking remain. That explains why approximately 50% of the 160,000 diagnoses now made for lung cancer are made among former smokers.
--One popular argument the scientific community often makes to encourage smokers to quit stems from the theory that all of the health effects of smoking are reversible shortly after cessation, regardless of the duration or intensity of smoking exposure. Unfortunately, this is just not true.
--Regarding lung cancer, smoking for about 25 years appears to trigger a biological switch that drives the growth of lung cells towards the development of lung cancer--even if the smoker quits. Thus, while quitting is the best option for a smoker of any age, damage to the respiratory system, including those that can result in cancer, may continue to plague the ex-smoker for years after quitting.
--Smokers (one pack a day for twenty or more years) have a ten- to fifteen-fold greater risk of developing lung cancer compared to those who have never smoked. The more you smoke--or smoked in the past--the greater your risk of lung cancer (and other smoking-related diseases). Public health experts have long argued that risk declines with time after you stop, but this may be much more true for risks of heart disease than for risks of cancer, particularly with a very long history of heavy smoking.
The Case of Peter Jennings
Take the case of Peter Jennings. News reports indicate he started smoking when he was thirteen years old (for him that would have been around 1951) and continued smoking heavily until the mid or late 1980s. That would be more than thirty-one years of exposure to the risks of smoking. It is unclear how much he smoked after giving up cigarettes in the 1980s (he acknowledges taking up smoking again after the 9/11/01 terrorist attacks).
Mr. Jennings, even if he was an ex-smoker after 2001, was at greatly elevated risk of lung cancer given the long history of exposure. The question then is this: what are the lessons to be learned from Peter Jennings? What can and should we do to reduce our own risk of being diagnosed with life-threatening lung cancer?
Advice for Risk Groups
For nonsmokers: Do not start smoking. Do not delude yourself into believing that you can "smoke 'til I'm thirty" or "smoke until I want to have kids" and come away unscathed, returning to the same risk file as a never-smoker. Smoking directly irritates and damages the respiratory tract. Each year, a one-pack-a-day smoker smears the equivalent of a cup of tar over his or her respiratory tract. This irritation and damage cause a variety of adverse effects, ones that can be reduced--but not entirely reversed--by quitting.
For current smokers: Quit now. Get assistance if necessary. Even if you have been smoking for many decades, you will be rewarded with health benefits, especially a rapid decline in risk from the number one cause of cigarette death: cardiovascular disease.
For (newly worried) former smokers: Be grateful you quit when you did. If you have smoked for many years--maybe decades--and now realize you have an elevated risk of lung cancer, consider the fact that among long-term, current smokers, the chances of developing lung cancer are in the 10%-15% range. If you quit ten or more years ago, your personal risk is below that range.
Screenings
What about regular lung cancer screenings? Well, talk it over with your own physician--but be keenly aware of the limitations here. Your physician may recommend a yearly chest X-ray. This may or may not assist in diagnosing lung cancer at an early, curable stage. (The American Cancer Society stopped recommending annual X-rays for smokers many years ago, although some physicians think such rays can be useful in finding early cancers.)
There has been some excitement in the medical community, and among the public, about screening using lower-dose CT scans--spiral or helical CTs--to enhance detection of early-stage lesions. There are several studies now underway to see if such techniques will lead to an improvement in the real bottom line: survival rate. Thus far, no study has shown an improvement in mortality rate from lung cancer in patient groups screened by chest X-ray or CT scan, but there have been some indications that larger-scale studies may show some beneficial impact. Meanwhile, the fact is that many more benign lesions or indolent growths of no importance to lifespan get detected than dangerous, early-stage tumors--in other words, these CT type tests can yield lots of "false positives," causing needless anxiety and even needless surgery. It seems counter-intuitive, but early detection has not proven to be helpful in saving lives from lung cancer...yet.
Whelan and Ross head the American Council on Science and Health, which runs the sites ACSH.org, HealthFactsAndFears.com, and theScooponSmoking.org.
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