Living Under a Cloud: Examining Air Pollution's Effects on Lung Cancer

It comes as no surprise that breathing clean air is better for a person than taking in polluted air, but new research proves the difference can be crucial for patients who have been diagnosed with lung cancer.

Researchers from the Keck School of Medicine at the University of Southern California (USC) found that the median survival of patients with early-stage lung cancers who lived in areas with high levels of pollution was approximately three years shorter.

The research is based on data from more than 350,000 patients in the California Cancer Registry who were diagnosed with lung cancer between 1988 and 2009. Researchers looked at patients with localized cancer and patients whose cancers had metastasized.

“There’s a growing number of articles out there that show air pollution is associated with lung cancer incidence and mortality,” says Sandrah Eckel, Ph.D., an assistant professor of preventive medicine at USC. “Due to the high case fatality rate, it’s actually been pretty hard to disentangle the relationship between air pollution and incidence or air pollution and mortality. We realized this lung cancer registry offered us an interesting opportunity to actually look at the effect of air pollution on survival after diagnosis.”

In those with localized lung cancer living in areas with higher levels of air pollution, the median survival was 2.4 years compared with 5.7 years in patients living in areas with lower levels. In cases in which lung cancer had metastasized, researchers observed shorter survival among patients overall, with little difference between high and low exposures of air pollution.

The pollutants studied in this analysis included nitrogen dioxide (NO2), ozone (O3) and particulate matter (PM10 and PM2.5). Eckel says strong associations were seen with N02, PM10 and PM2.5. Ozone pollution elicited the smallest change in median survival.

If patients diagnosed with early-stage lung cancer are concerned about air quality, Eckel explains that there are some common-sense precautions that all people — not just those with lung cancer — can take.

“If you’re planning to exercise, which is really important, maybe take into account what the air quality alert is for that day, and if it’s going to be a high pollution day, don’t exercise outside,” she says. “Exercise inside or rearrange your schedule to exercise at the time of day when air pollution is lower or in a park that’s not close to a busy roadway. If you’re at home and it’s a hot day out, rather than opening the windows, turn on the air conditioning to keep pollution out.”

Eckel adds that having an air filtration system in your home or using the recirculate setting on your car’s air conditioning system while sitting in heavy traffic is beneficial to one’s health, as well. She also notes that coastal regions tend to have cleaner air.

“One takeaway that I find interesting is that there’s been an emphasis on advance screening to detect early-stage lung cancer, so I think that we’re going to be seeing more of it. These are the people who we found air pollution had the biggest effect on,” Eckel says. “I think that the issue of air pollution for them is really important.”

While this study revealed important findings, Eckel says more studies need to be completed, such as possibly an intervention study to determine the effect of air filters in homes.