Wildfire pollution may lower survival of lung cancer patients

Breathing in wildfire pollution may make it harder for people with lung cancer to survive, according to a new study from UC Davis Comprehensive Cancer Center researchers.

The study looked at more than 18,000 people in California who had non-small cell lung cancer (NSCLC), the most common kind of lung cancer, between 2017 and 2020. It found that people who were exposed to more wildfire-caused air pollution in the year after their cancer diagnosis were more likely to die from the disease.

The culprit is a tiny invisible toxin in the air

Wildfire-related air pollution contains tiny harmful particles called PM2.5 that can get deep into the lungs. The study found that patients who breathed higher levels of PM2.5 had a 20% greater risk of dying from lung cancer.

“The research tells us that there are small particles in the air that could make lung cancer worse,” said cancer center oncologist Surbhi Singhal. She is presenting the findings at the annual meeting of the American Society of Clinical Oncology on May 31.

The study used advanced modeling to estimate daily air quality at patients’ home addresses. It also factored in data from satellites, weather models, smoke forecasts and air quality monitors.

Impact on people with late-stage lung cancer

People with advanced cancer (Stage 4) who had never smoked were especially affected—their risk of dying from cancer went up by 55% if they were exposed to high levels of air pollution.

Interestingly, the study found patients with Stage 4 lung cancer with a history of smoking who were treated with immunotherapy actually had better survival rates during days of extremely high PM2.5 toxin levels. These levels were likely due to wildfire smoke instead of background air pollution. This surprising trend suggests that smoke-related changes in the body may interact with certain treatments—a finding the researchers say deserves further study.

Action needed to protect people

“As wildfires become more frequent and intense in California and other parts of the U.S., we need targeted health strategies to protect cancer patients and others with serious health problems,” Singhal said. “These results highlight the urgent need to protect vulnerable populations living in wildfire-prone regions.”