Ask an Expert: If there’s no lung cancer in your family history, is it safe for you to smoke?

Q: "Both of my parents smoked their entire lives and never developed lung cancer. My father's parents were the same. With this family history, do I still need to worry about lung cancer? I only smoke about a pack a week."

Answer from John R. Handy, Jr., M.D., co-director of Providence Thoracic Oncology Program and director of Providence Thoracic Surgery Program

One pack of cigarettes a week is not a huge amount, but yes, you are still at risk of developing lung cancer. Every cigarette you smoke introduces cancer-causing chemicals into your body.

In addition, if your parents and grandparents smoked around you as a child, you were unwittingly smoking a pack a day – or whatever amount they smoked – in the form of secondhand smoke. Secondhand smoke is not as bad as firsthand smoke is, but it is still dangerous and can cause lung cancer. (You might think about whom you are now exposing to secondhand smoke.)

Your parents and paternal grandparents were surely fortunate to avoid lung cancer. But if not lung cancer, what did they die of? Smoking greatly increases the risk of coronary heart disease, emphysema, stroke and peripheral artery disease. It also puts a drag on quality of life. Smokers lose their breath walking up a flight or two of stairs. They cough, they catch colds, they smell of stale cigarettes – and they spend a lot of money on tobacco.

Children cannot inherit an ability to avoid lung cancer. Inherited genetics play a greater role in cancer formation than in prevention. That means genetics may make a person more susceptible to the out-of-control cellular growth that leads to tumors. But genetics don't protect you from the cancer-causing effects of cigarette smoke. Even with your family history, carcinogens in cigarette smoke can alter or mutate genes in a way that, under certain complex cellular circumstances, lead to cancer.

Your risk of lung cancer is related to the amount you smoke and the length of time you have smoked – or were exposed to secondhand smoke. Being a light smoker is not as good as not smoking at all. I'd like to see you quit, especially given your likely exposure to secondhand smoke when you were young. About 90 percent of lung cancers are caused either by smoking personally or by secondhand smoke; 85 percent of lung cancers are diagnosed at an advanced stage. The five-year survival rate is 15 percent.

Lung cancer is a miserable way to die. The good news is you can cut your risk: The longer you abstain from cigarettes, the more your risk of developing cancer falls. It's much easier to prevent lung cancer than to treat it. Don't smoke. It's the single best thing you can do to positively affect your health.

October 2005