Over 100 years ago, lung cancer was relatively uncommon. But this was well before Hollywood glamorized smoking and the tobacco industry launched mass advertising campaigns.
Fast forward to today, and the primary risk factor for developing lung cancer is cigarette smoking, which accounts for approximately 90% of all cases.
What’s more, lung cancer is now the leading cause of cancer deaths, with approximately 125,000 expected deaths in the U.S., more than breast, prostate and colon cancers combined.
Cigarette Smoke and the DNA Connection
Lung cancer occurs when cells in the lungs undergo changes in DNA caused by cigarette smoke. DNA, or deoxyribonucleic acid, is present in the cells of every living organism and carries genetic information necessary for development and functioning, including susceptibility to diseases like cancer.
Cigarette smoke contains over 7,000 chemicals, including carbon monoxide, hydrogen cyanide, ammonia, arsenic, formaldehyde and nicotine. Many are carcinogens — substances known to cause cancer.
When someone smokes, the chemicals enter the lungs and affect the entire body, including the DNA. Smoking causes lung cancer by damaging genes inside normal lung tissue cells, transforming them into cancerous cells that grow and spread uncontrollably.
Initially, the body may be able to repair this damage. However, with repeated exposure, healthy lung cells are increasingly damaged and, over time, may develop into cancer.
Similarly, this is why secondhand smoke is so dangerous. While the doses of carcinogens received from secondhand smoke exposure are far less than with active smoking, exposure can begin at birth and extend across the entire lifespan, increasing the risk of lung cancer.
While we know that smoking increases a person’s risk of lung cancer, it’s less clear why only some smokers develop the disease. Studies suggest it may be genetic, and DNA repairs are more active in the genes of certain smokers, thus protecting them.
Quitting Isn’t Easy, But it’s Worth it
Even if years of smoking have damaged a person’s lungs, whenever I’m asked if quitting is worthwhile, I always emphatically tell my patients, “Yes, it’s definitely worth quitting.”
According to the American Lung Association, after stopping for even:
- 20 minutes — your heart rate drops to a normal level
- 2 weeks to 3 months — your risk of a heart attack is lowered, and lung function improves
- 1 to 9 months — coughing and shortness of breath are reduced
- 1 year — your added risk of coronary heart disease is half that of a smoker’s
The lowered risk for lung cancer becomes apparent within five years and continues to decline the longer you refrain from smoking. Studies show that former ѕmоkers who had been abstinent for more than 15 years had an 80 to 90% reduction in risk of lung cancer compared with current smоkers.
However, some lung damage remains in former smokers, and risk remains higher than in individuals who never smoked, even after prolonged periods of complete smoking cessation. That said, surveys that show adults who quit gained six to 10 years of life expectancy, depending on the age at which they quit.
Seek Support to Stop Smoking
I admit that stopping smoking is not easy. So, I usually suggest a decrease in the amount you smoke, and then eventually, hopefully, you’ll entirely quit.
All smokers should be offered therapy. A combination of medication therapy and behavioral therapy, such as a smoking cessation clinic, gives the best results.
Talk with your doctor about your risk factors for lung cancer. You may meet the criteria for a non-invasive, low-dose CT scan, which is the best way to detect lung cancer early. It’s quick, painless and only takes about 20 minutes.
Dr. Igor Medic, is a Sharp Community Medical Group board-certified oncologist affiliated with Sharp Grossmont Hospital.
