Ten Myths About Lung Cancer

Lung cancer causes more deaths worldwide than any other form of cancer. There are many misconceptions relating to the causes and likelihood of developing the disease. Some of the common myths about lung cancer are discussed below.

Myth 1: Lung Cancer Is A Disease Of The Elderly
Around 6% of lung cancer cases occur in people aged under 50 and 20% in people under 60. In the United States alone, 44,000 people aged under 60 develop the disease each year, the majority of them smokers. A smoker has around a 4% chance of developing lung cancer by the age of 60. Lung cancer is second only to heart disease as the leading cause of death in smokers aged 40 to 60.

Myth 2: Lung Cancer Is Exceedingly Rare In Non-Smokers
Around 30,000 cases of lung cancer are diagnosed in non-smokers in the United States each year, about 15% of total cases. Even among non-smokers, lung cancer is still one of the 10 most common forms of cancer. There are several risk factors for lung cancer unrelated to smoking including radon gas exposure, air pollution, asbestos exposure, and genetic factors.

Myth 3: Smoking Is More Prevalent In Japan Than The USA However Lung Cancer Rates In Japan Are Lower Than The USA, Therefore Smoking Is Not As Strong A Risk Factor For Lung Cancer As Commonly Believed
While it is true that lung cancer rates in Japan are low, despite a relatively high smoking rate, this appears to be the result of naturally low cancer rates in the country overall. Studies of Japanese men typically find that smokers have around a 10-fold increased risk of developing lung cancer compared to non-smokers, a similar figure to the United States. In both countries, smoking is by far the most important risk factor for lung cancer.

Myth 4: Due To Recent Advances In Medical Care, Lung Cancer Will Probably Be Curable In The Next Few Decades
Lung cancer is actually one of the few forms of cancer that has seen very little improvement in survival statistics over the last few decades. 5-year survival for lung cancer increased from 12% to 17% from 1978 to 2008 – a very modest improvement. There are no guarantees that lung cancer survival over the next 30 years won’t continue to remain low. Because early lung cancer is typically asymptomatic, the majority of cases are quite advanced at time of diagnosis and are very difficult to treat. Most lung cancer cases are considered terminal at diagnosis. Only Stage I and II non-small-cell lung cancers, which make up less than a quarter of all cases, have a realistic chance of cure.

Myth 5: The Effects Of Smoking Are Over-Estimated Because All Lung Cancer Deaths In Smokers Are Wrongly Assumed To Be A Result Of Their Smoking Habit
Statisticians estimate the risks associated with lung cancer by comparing lung cancer rates in non-smokers with smokers. For example, if lung cancer rates in smokers are estimated at 200 per 100,000 per year and rates in non smokers at 10 per 100,000 per year then smoking is associated with a 20-fold increase in the risk of lung cancer. This doesn’t mean that ever case of lung cancer in smokers is assumed to be a result of their habit, only the difference between the smoking and non-smoking rate is assumed to be the result of smoking. In the above example, 95% (190/200) of lung cancer cases in smokers would be directly attributable to smoking.

Myth 6: Light Smoking Of A Few Cigarettes A Day Has A Negligible Impact On Lung Cancer Risk
There hasn’t been a threshold established under which smoking has no impact on lung cancer risk. Studies of light and intermittent smokers typically find increased risk of lung cancer relative to non-smokers. For example, a Norwegian study, published in the journal Tobacco Control in 2005, found that the relative risk of lung cancer in smokers of 1-4 cigarettes a day compared to non-smokers was 2.79 and 5.03 for men and women respectively.

Myth 7: None Of My Relatives Died Of Lung Cancer Despite Many Of Them Smoking Heavily, Therefore I’m Not Overly Concerned About The Effects Of Smoking On My Health
While genetics play a role in determining an individuals risk of developing lung cancer, a lack of family history of the disease in no way guarantees an individual won’t develop lung cancer. The majority of people who develop lung cancer have no 1st or 2nd degree relatives who suffered the disease.

Myth 8: I’m A Smoker But Because I Exercise Regularly, Don’t Drink Heavily And Eat A Healthy Diet, My Chances Of Getting Lung Cancer Are Low
Neither alcohol consumption or physical fitness have an effect on lung cancer risk. There is some evidence that diets rich in fruits and vegetables have a protective effect on lung cancer however a heavy smoker with a healthy diet is still at a much greater risk of lung cancer than a non-smoker with a poor diet.

Myth 9: There is No Evidence Or Conflicting Evidence That Passive Smoking Causes Lung Cancer
Most studies with a sufficiently large sample size find that passive smoking is a risk factor for lung cancer however the risks are actually quite small. A review of second hand smoking, published by the International Agency for Research on Cancer (IARC) in 2004, estimated that lung cancer risk was about 20-30% higher in non-smokers who were exposed to second hand smoke from their spouses.

Occupational exposure to passive cigarette smoke throughout a typical 40 year working life, for example in bar workers where smoking bans are not in place, has been estimated to increase an individuals lifetime risk of developing lung cancer by 0.1-0.4%. Low-level exposure to cigarette smoke outside of the above scenarios (for example occasional sharing of a car with a smoker), probably has a negligible effect on lung cancer risk.

Myth 10: Marijuana Smoking Causes Lung cancer
Interestingly, no link between marijuana smoking and lung cancer risk has been established however it is difficult to get a definitive idea of the health risks of marijuana smoke relative to cigarette smoke because very few people smoke marijuana heavily.