Air pollution may be contributing to shorter lifespans for lung cancer patients, a new study has found.
The research, which adds to the pile of evidence on the negative health impacts of airborne toxins, found that people diagnosed with early-stage lung cancer are most at risk of premature deaths. This is especially true for patients with adenocarcinoma, the most common form of non-small cell lung cancer, which comprises 80% of all lung cancer cases, Medscape reports.
The study, led by Sandrah Eckel, an assistant professor in the Division of Biostatistics at the University of Southern California, came from US medical data that analyzed the health outcomes of 352,000 people in California diagnosed with lung cancer from 1988 and 2009.
The research team theorized that if ambient air pollution could influence the progression of lung cancer, then pollutants inhaled by patients could also affect the development of tumors “through the same mechanistic pathways to shorten survival after diagnosis.”
They used four air pollution measures (PM10, PM2.5, NO2, and ozone), calculated using data provided by the US Environmental Protection Agency air quality monitoring stations and mapped to the residential addresses of the patients at the time they were diagnosed.
The team also computed the distance to the nearest highways to account for traffic exposures and included information on socioeconomic status and measures of urbanicity.
The study found that people with early stage lung cancer survived for an average of 3.6 years, which fell to 2.4 years when they were exposed to high levels of particulate matter.
Overall, the finding stated that patients with early-stage lung cancer had a 30% higher risk of death when exposed to nitrogen dioxide, 26% when exposed to larger particulate matter, and 38% when exposed to smaller particulate matter.
The chances of patients with the disease living five years after diagnosis was 30% for those exposed to the highest air pollution levels compared to 50% among those least exposed to the same.
Jaime Hart, of the Channing Division of Network Medicine, Brigham and Women’s Hospital and Harvard Medical School in Boston, who wrote an accompanying editorial on the study, says that there were some limitations in the study, such as not being able to account for possible changes in lifestyle habits or other treatments the patients might have undergone during the course of the research.
However, she adds, it does provide compelling evidence that something should be done about air pollution to increase the chances of cancer survival.
The study was published in the journal Thorax.