While it’s been known over the past decade that air pollution can trigger cancer, the exact reason why is largely unknown. A new study, presented at this year’s European Society for Medical Oncology Congress, unravels how air pollution can cause lung cancer, especially among those who don’t have a history of smoking.
The study suggests that air pollution, which is categorized as a “group 1 carcinogen” along with other exposures such as tobacco smoke, radiation, asbestos and radium, can trigger lung cancer in nonsmokers because air pollution particles may promote a change in cells in the airway. Exposure to airborne particle matter at 2.5 micrometers in diameter or smaller can drive mutations in a specific gene called EFGR. This mutation is seen in about half of people with lung cancer who have never smoked.
“Gene mutations are a hallmark of cancer,” said Dr. Matthew Schabath, an epidemiologist at Moffitt Cancer Center who focuses on lung cancer. “When a normal gene is mutated, often as the result of long-term exposures to substances like tobacco smoke or air pollution, the cells containing these mutations embark on a frenzied and uncontrolled growth. This uncontrolled growth is the beginning of the formation of a tumor.”
When analyzing the study’s data, researchers found that increasing levels of air pollutants were associated with overall increases in the risk of EGFR-related non-small cell lung cancer in individuals living in England, South Korea and Taiwan.
“This study gets at the ‘how’ a specific exposure causes cancer. And getting at the how may lead to important downstream discoveries, such as novel therapeutics that will treat these lung cancers, ways to search for these mutations, such as liquid biopsies, among people not diagnosed with lung cancer as a potential method for early detection, or ways to modify current lung cancer screening guidelines to include people living and/or working in areas of high air pollution.”
Particle matter or particle pollution in the air is a mix of solid and liquid droplets and are typically found in vehicle exhaust and fossil fuels. They can also be emitted directly from construction sites, unpaved roads, smokestacks and fires. These particles are associated with non-small cell lung cancer risk, accounting for over 250,000 lung cancer deaths globally per year.
In order to reduce exposure to these dangerous particles, patients should be advised to stay indoors on high air pollution days, reduce outdoor air from entering indoors, clean indoor air with air filters and limit physical exertion in areas of high pollution.
While 1 out of 6 smokers will get lung cancer, nationally about 20% of lung cancer patients are never smokers.
Risk Factors include:
- First-degree relative with lung cancer
- Exposure to second-hand smoke
- Exposure to radon or asbestos
- High-saturated inflammatory diet
- Lack of exercise
- Other inflammatory lung disease, such as emphysema
If you’d like to refer a patient to Moffitt, complete our online form or contact a physician liaison for assistance. As part of our efforts to shorten referral times as much as possible, online referrals are typically responded to within 24 - 48 hours.