The problem: understanding why people get lung cancer

Epidemiology is the study of the factors contributing to, and the occurrence and distribution of, health and disease in a given population. Lung cancer epidemiology is about tracking the patterns and causes of the disease. Why do people get lung cancer? Studying the epidemiology of lung cancer matters because it impacts people worldwide.

In the United States alone, estimates are that 1 in 16 people will be diagnosed with lung cancer during their lifetime. An estimated 238,340 Americans will be diagnosed with lung cancer this year. It’s the “hidden” women’s cancer, garnering less federal research funding than other cancers while killing more women than any other cancer. It’s also the leading cause of cancer deaths among both Black and Asian Americans.

Worldwide, over 2.2 million people will get lung cancer each year. Men in over 35 countries are more likely to be diagnosed with lung cancer than any other cancer. In Europe, more people die from lung cancer than any other cancer. In North America, the disease kills more people than breast, prostate, and colon cancers combined.

On average, 8 out of 10 people with lung cancer (80–85%) are diagnosed with non-small cell lung cancer (NSCLC), with the remaining (15–20%) diagnosed with small cell lung cancer (SCLC).

Learn about our research on the epidemiology of young lung cancer.

While lung cancer is the leading cause of cancer deaths, the trajectory of lung cancer looks very different in men and women. Since 1984, the rate of new lung cancer cases in the US has dropped 36% for men—but it’s risen 84% for women. There are also stark racial differences. Black men and women are more likely to get lung cancer than white Americans, even though their overall exposure to cigarette smoke, the number one risk factor for lung cancer, is lower.

Most lung cancers are diagnosed in people 65 and older. More recently, however, younger adults (and younger women in particular) are being diagnosed with lung cancer—and numbers are increasing. In addition, more adults ages 20–49 who have never smoked are now being diagnosed with lung cancer.

While 1 in 16 people will be diagnosed with lung cancer in their lifetime, there are risk factors that put people at a higher risk of developing the disease. Smoking cigarettes is the most common risk factor for lung cancer, as the chemicals in cigarette smoke contain at least 69 known cancer-causing agents. Smoking cigarettes, cigars, pipes, and waterpipes are all associated with a higher risk of lung cancer.

While smoking cigarettes is the biggest risk factor, there are other factors that increase one’s risk for developing the disease:

• Environmental exposure happens when you come into contact with something in the air, water, food, or soil that may be harmful to your health.
• ‍Workplace exposure means that you encountered something harmful while you were on the job. Exposure to compounds such as radon, asbestos, diesel fumes, arsenic, coal products, nickel compounds, and secondhand smoke are all factors that increase your risk of lung cancer.
• If you have a family history of lung cancer (if someone in your family has or had lung cancer), then you are at a higher risk of developing lung cancer.
• If you have a personal history of cancer (such as breast cancer), then you are at a higher risk of developing lung cancer. ‍
• Chronic lung disease, including emphysema, pulmonary fibrosis, and COPD are all associated with a higher risk of developing lung cancer.

While researchers understand some of the risk factors for lung cancer, others remain a mystery. Our study, the Epidemiology of Young Lung Cancer (EoYLC), is focused on people under age 50 diagnosed with lung cancer. By looking at demographics, medical history, and other factors, we’re trying to crack the code as to why more and more young people are developing lung cancer.