THURSDAY, April 23, 2026 (HealthDay News) -- Wildfire smoke (WFS) exposure is associated with an increased risk for certain cancers, according to a study presented at the annual meeting of the American Association for Cancer Research, held from April 17 to 22 in San Diego.Qizhen Wu, Ph.D., from the University of New Mexico Comprehensive Cancer Center in Albuquerque, and colleagues examined associations between WFS exposure and cancer incidence among 91,460 participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. WFS exposure was quantified monthly at participants' residences using near-ground WFS fine particulate matter (PM2.5), WFS black carbon, and satellite-derived WFS plume-day counts. Using 36-month moving averages preceding each month, WFS exposure was modeled as a time-varying variable.During 2006 to 2018, the researchers identified incident cases of 1,758 lung, 800 colorectal, 1,739 breast, 242 ovarian, 896 bladder, and 1,696 hematopoietic cancers and 1,127 melanomas. Significant associations were seen for WFS exposure with increased risks for lung, colorectal, breast, bladder, and hematopoietic cancers; for most analyses, an approximate linear dose-response was observed. There were associations seen for each 1-µg/m3 increase in the 36-month moving-average of WFS PM2.5 with increased risks for lung, colorectal, breast, bladder, and hematopoietic cancers (hazard ratios, 1.92, 2.31, 2.09, 3.49, and 1.63, respectively); for ovarian cancer and melanoma, no associations were found. WFS plume-day count results were generally consistent with those for WFS PM2.5."For the general public, the key message is that wildfire smoke is not only a short-term respiratory or cardiovascular concern -- chronic exposure may also carry long-term cancer risks," Wu said in a statement.Press ReleaseMore Information.Sign up for our weekly HealthDay newsletter