Abstract
BACKGROUND: Exposure to ionizing radiation is known to increase the risk of lung cancer. However, studies on the effect of environmental radiation associated with ambient particle air pollution on lung cancer survival are limited. We investigated the association between ambient beta particle radioactivity (PR-β) after a diagnosis and lung cancer survivals. METHODS: The Boston Lung Cancer Survival (BLCS) cohort consisted of histologically confirmed patients enrolled at Massachusetts General Hospital (MGH) and the Dana-Farber Cancer Institute (DFCI) in Boston, U.S. The primary outcomes included overall survival, 5-year survival, and 3-year survival probability. We estimated ambient PR-β exposure at the ZIP code of residence from 2001 through 2017. Cox-proportional hazards models were constructed to estimate hazard ratios (HRs) for the associations between ambient PR-β and survival outcomes while controlling for covariates. RESULTS: The analysis included 2795 patients with complete information, with 97,330 person-months of follow-up. The interquartile range (IQR) increase in PR-β was significantly associated with worse overall survival (HR:1.63, 95% CI:1.52, 1.76), 5-year survival (HR:1.33, 95% CI:1.23, 1.44), and 3-year survival (HR:1.22, 95% CI:1.12, 1.33) while adjusting for covariates, including age at diagnosis, sex, race, smoking, stage, histology, and adjusted gross income. Similar associations were found while additionally adjusting for the estimated residential radon exposure. In addition, the survival associated with PR-β exposure was significantly worse for patients in the early stages (HR:2.16, 95% CI:1.84, 2.52). CONCLUSION: The findings from this study provide new evidence suggesting that environmental exposure to radioactive particles after lung cancer diagnosis may have a pronounced effect on survival, particularly in patients with early stages.