Temporal Association of Cancer Incidence with World Trade Center Rescue/Recovery Work

Abstract

BACKGROUND AND AIM: The latency period between exposure to carcinogens and the diagnosis of cancer is of interest from both clinical and public health perspectives. The collapse of the World Trade Center (WTC) towers on 9/11/2001, and the subsequent months of rescue/recovery work led to the widespread exposure of responders to hazardous materials including carcinogens. While earlier studies reported increased risks of prostate cancer, melanoma, thyroid cancer, and non-Hodgkin’s lymphoma, none have evaluated the latency period associated with these toxic exposures. METHODS: Participants from the WTC Combined Rescue/Recovery Cohort were observed between 3/12/2002 and 12/31/2015. Cancer data were obtained via linkages with 13 state registries. Poisson regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI), using the New York State (NYS) population as reference. In internal analyses, time (date) first worked at the disaster site was used as a proxy for intensity of exposure. Changepoints in the HRs were estimated using profile likelihood. RESULTS:Beginning in 2007, an increased risk of prostate cancer was observed among WTC rescue/recovery workers when compared with NYS (HR: 1.2, 95% CI 1.2-1.3). For melanoma, no increased risk was detected between 2002 and 2004, but from 2005-2015, the HR was 1.3 (95% CI 1.2-1.5). We observed no changepoint in thyroid cancer incidence, but overall, the rates were twice that of the NYS population (HR: 2.3; 95% CI: 2.0-2.7). A small increase in non-Hodgkin’s lymphoma incidence was detected between 2002 and 2003 (HR: 1.3; 95% CI: 0.6-2.8), but not in subsequent years. An elevated non-Hodgkin’s lymphoma risk was observed from 2004-2015 among participants who were most highly exposed, according to time first worked on the WTC effort (HR:1.3; 95% CI 0.9-1.9). CONCLUSIONS:This research may increase understanding of the latency period between environmental exposure and cancer incidence in human populations. KEYWORDS: cancer, occupational exposures, epidemiology