While lung cancer generally affects long-time smokers, the number of people who have never smoked and are diagnosed with lung cancer is increasing. In addition, lung cancer appears to be increasing among 30- and 40-year-olds who have never smoked a day in their lives. Experts are still trying to figure out exactly why. But potential causes might be high levels of radon in homes (which can easily go unnoticed), exposure to second-hand smoke, and family history.
Furthermore, heavy air pollution, as well as carcinogenic substances such as asbestos, may also be to blame.
Screening is not an option but a necessity
Unfortunately, there is no easy way to identify the disease in non-smokers. Doctors can screen for lung cancer using low-dose CT scans. But testing is reserved for people who are known to be at high risk. Currently, the population most affected by lung cancer screening is aged 55 to 80 and has smoked or quit smoking in the past 15 years. Without screening, it is difficult to identify lung cancer at an early stage. By the time most people have symptoms that are worrisome enough to warrant a call to their doctor, the cancer may be advanced.
Spot the early symptoms of lung cancer
Given the increase in the number of lung cancers in people who do not seem to have risk factors for the disease, it is important to pay attention to concerning symptoms and report them to the doctor.
Here are some warning signs to watch out for.
1 Shortness of breath
But it is also a symptom of lung cancer. If you’re an active person who can no longer climb a few flights of stairs without stopping for a breath, this is an unusual and worrisome symptom.
2 A chronic cough
Catching a cold or the flu is common, especially in winter. And the cough can last longer than expected (on average 18 days). A dry, persistent, stubborn cough that has lasted four to six weeks or more, however, may indicate that you need an x-ray to check the condition of your lungs.
3 Spitting Blood
This is never normal, and it requires urgent evaluation. The causes can range from lung cancer to bronchitis, or a viral or bacterial infection.
4-5 Weight loss, fever, night sweats
Weight loss (without dieting), fevers unrelated to an illness, or profuse night sweats are all symptoms that will prompt your doctor to evaluate you for hidden cancer.
No mystery, smoking is the leading cause of lung cancer, followed by radon exposure. Lung cancer involves the uncontrolled growth of abnormal cells in the lining of the bronchi (tubes that take air in and out of the lungs) and other parts of the lungs. Researchers have identified harmful substances (carcinogens) that can damage cells and lead to lung cancer. Genes may also play a role. Knowing the causes of lung cancer can help you take appropriate steps to minimize risk factors and recognize symptoms.
Smoking is the number one risk factor for lung cancer. It contributes to 80% of lung cancer deaths in women and 90% of lung cancer deaths in men. Cigar and pipe smoking are almost as likely to cause cancer as cigarette smoking.
Although tobacco smoke is the main cause of lung cancer, not all smokers develop the disease. Second-hand smoke, which is the smoke inhaled from another person’s cigarette, cigar, or pipe, can also lead to lung cancer.
Exposure to radon, a natural, invisible gas that can be trapped in buildings, is the second leading cause of lung cancer. About 10% of all lung cancer cases are caused by radon gas, resulting in approximately 21,000 lung cancer deaths each year.
Asbestos is a material used for insulation in construction. When asbestos fibers break loose, they can become airborne and dangerous to inhale, causing scarring and inflammation in the lungs as they build up. Exposure to asbestos increases the risk of lung cancer and mesothelioma, a rare type of cancer that develops in the pleura, the membrane that surrounds the lungs. Numerous studies have shown that the combination of smoking and exposure to asbestos is particularly dangerous.
Particulate pollution (a mixture of tiny solid and liquid particles in the air) can cause lung cancer. Between 1% and 2% of lung cancer cases are caused by outdoor air pollution. Common culprits of air pollution are diesel truck exhaust, coal-fired power plants, and wood smoke.
Other potential causes of lung cancer include:
Radiation therapy to the chest area as a treatment for certain cancers can cause lung cancer.
Researchers are investigating whether certain foods or supplements may contribute to lung cancer. For example, studies have shown that smokers who take beta-carotene supplements are more likely to develop lung cancer.
Exposure to several other substances has been linked to the development of lung cancer. These include arsenic (in drinking water), chromium and nickel.
However, a Swedish study that followed nearly 50,000 men over a 40-year period found a link between marijuana use and lung cancer. Heavy marijuana smokers, those who reported having smoked more than 50 times in their lifetime, were twice as likely to get lung cancer as those who did not smoke marijuana.
Inherited genetic mutations
Some people inherit certain genetic mutations, or changes to their DNA, that can increase their risk of developing cancer.
These genetic changes alone do not cause many cases of lung cancer, but they play a role in some cases. For example, people who inherit certain mutations on chromosome 6 are more likely to develop lung cancer, even if they don’t smoke. Also, some people inherit faulty DNA repair enzymes that make them more susceptible to cancer-causing chemicals. Doctors are working on developing specific tests to identify people with these genetic abnormalities.
Acquired genetic mutations
Most often, the genetic mutations that impact lung cancer are “acquired”, rather than inherited. This means that the defect develops over your lifetime. These acquired mutations often occur due to exposure to carcinogenic substances, such as tobacco smoke. But some genetic mutations occur without a known cause and may just be random events. Everyone develops mutations in cells during their lifetime, but toxic exposures cause more of these mutations, increasing the risk of acquiring a cancer-causing mutation.
Gene mutations can also make some lung cancers more aggressive.
Lung cancer in men and women
Historically, lung cancer rates have always been higher in men than in women. But a study published in the New England Journal of Medicine in May 2018 found that lung cancer rates are now higher in women than in men among people born since 1965.
For example, lung cancer rates among white women aged 40-44 rose from 12% lower than men during the 1995-1999 period to 17% higher during the 2010-2014 period.
Sources
https://academic.oup.com/jnci/article/109/7/djw295/2962336
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6462682/
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