Lung cancer is the leading cause of cancer death and the second most diagnosed cancer in both men and women in the United States, according to the Centers for Disease Control and Prevention.
In 2011, 14 percent of all cancer diagnoses and 27 percent of all cancer deaths were due to lung cancer. Find out more about the types of lung cancer and treatment options in this Q&A with lung cancer expert David Wilson, MD, MPH, of UPMC Hillman Cancer Center.
Q. What are the different types of lung cancers and how are they treated?
Lung cancer is broken down into two types: small cell lung cancer, which makes up 20 percent of all lung cancers and is most closely associated with smoking, and non-small cell cancers, which make up the other 80 percent of lung cancers.
Small cell lung cancer is very aggressive and fast growing and has its own staging system. If staged as “limited”, small cell lung cancer has not spread outside of the chest. When it’s staged as “extensive”, the cancer has metastasized, or spread, to other parts of the body, such as the brain and bones. Limited small cell lung cancer has a 20 percent cure rate; the cure rate for extensive small cell lung cancer is just 1 to 2 percent.
Treatment for small cell lung cancer always involves chemotherapy. In addition, it often includes whole-brain radiation due to the high likelihood that this type of cancer will metastasize or spread to the brain.
Non-small cell lung cancers include squamous cancer, which represents 40 percent of non-small cell lung cancers, and adenocarcinoma, which makes up the other 60 percent. At one time, squamous cancer was the number one type of non-small cell lung cancer — but lower smoking rates have resulted in its decline.
For many years, the standard of care for non-small cell lung cancers localized to the lung was surgical removal of the entire lung, or a total lobectomy. In most cases today, surgical removal of only the diseased portion of lung, called a sub-lobar resection or segmentectomy, can be performed to preserve lung function.
Surgery is usually combined with chemotherapy and/or radiation. When cancer has spread to the lymph glands, surgery almost always includes both chemo and radiation.
Q. How can someone get lung cancer if they’ve never smoked?
In men who get lung cancers, only about 6 to 8 percent have never smoked. When nonsmoking men get lung cancer, it can be from inhaling second-hand smoke, having a genetic predisposition to the disease, or through occupational or environmental exposure.
A generation ago, asbestos was the key exposure culprit in lung cancer among nonsmoking men. Since asbestos is no longer widely used, the biggest exposure danger is radon, a known carcinogen or cancer-causing agent.
Radon gas comes from the radioactive breakdown of naturally occurring uranium and other elements in soil and rocks that is released into the air we breathe and the homes in which we live. Shale adds to radon levels in different parts of the country, including western Pennsylvania, where there are large deposits of Marcellus shale underground.
Of all the women who get lung cancer, nonsmoking women make up about 18 to 20 percent of cases. Second-hand smoke is a prime cause of these cancers, particularly in the African-American community where fewer women smoke cigarettes but many are exposed to second-hand smoke from male smokers in the household.
Hormones also play a part in lung cancer in women. Researchers at the University of Pittsburgh were among the first to link female hormone estrogen to genetic mutations in lung tumors in women. Estrogen receptors ERα and ERβ have been detected on lung cancer cells and recent evidence suggests that hormone replacement therapy may increase both the incidence of, and mortality from, lung cancer in women.
David O. Wilson, MD, MPH, is associate director of the Lung Cancer Center at UPMC Hillman Cancer Center