Temporal association of prostate cancer incidence with World Trade Center rescue/recovery work

Abstract

Background: The World Trade Center (WTC) attacks on 11 September 2001 created a hazardous environment with known and suspected carcinogens. Previous studies have identified an increased risk of prostate cancer in responder cohorts compared with the general male population.

Objectives: To estimate the length of time to prostate cancer among WTC rescue/recovery workers by determining specific time periods during which the risk was significantly elevated.

Methods: Person-time accruals began 6 months after enrolment into a WTC cohort and ended at death or 12/31/2015. Cancer data were obtained through linkages with 13 state cancer registries. New York State was the comparison population. We used Poisson regression to estimate hazard ratios and 95% CIs; change points in rate ratios were estimated using profile likelihood.

Results: The analytic cohort included 54 394 male rescue/recovery workers. We observed 1120 incident prostate cancer cases. During 2002-2006, no association with WTC exposure was detected. Beginning in 2007, a 24% increased risk (HR: 1.24, 95% CI 1.16 to 1.32) was observed among WTC rescue/recovery workers when compared with New York State. Comparing those who arrived earliest at the disaster site on the morning of 11 September 2001 or any time on 12 September 2001 to those who first arrived later, we observed a positive, monotonic, dose-response association in the early (2002-2006) and late (2007-2015) periods.

Conclusions: Risk of prostate cancer was significantly elevated beginning in 2007 in the WTC combined rescue/recovery cohort. While unique exposures at the disaster site might have contributed to the observed effect, screening practices including routine prostate specific antigen screening cannot be discounted.

Keywords: environmental exposure; exposures or occupational groups; longitudinal studies; materials; medical oncology; risk assessment.

Figure 1

Flow of study participants. FDNY, Fire department of the City of New York; GRC, General Responder Cohort; WTCHR, World Trade Centre Health Registry.

Figure 2

Adjusted prostate cancer incidence rates. (a) WTC combined rescue recovery cohort versus NYS. WTC, NYS, comparison population; models are controlled for race/ethnicity and age; rates are centred at non-Hispanic white race/ethnicity and ages 50–54; rates are displayed per 100 000 person-years; blue lines: smoothed adjusting incidence curves for WTC combined rescue/recovery cohort; red lines: smoothed adjusting incidence curves for NYS comparison population. line shadows represent 95% CI. (b) WTC combined rescue recovery cohort by exposure category models are controlled for race/ethnicity and age; rates are centred at non-Hispanic white race/ethnicity and ages 50–54; rates are displayed per 100 000 person-years; red lines: smoothed adjusting incidence curves for point estimates for each year of WTC combined rescue/recovery cohort who first arrived at the WTC disaster site on 11 September or were caught in the dust cloud; blue lines: smoothed adjusting incidence curves for WTC combined rescue/recovery cohort who first arrived at the WTC disaster site on 12 September; green lines: smoothed adjusting incidence curves for WTC combined rescue/recovery cohort who first arrived at the WTC disaster site on 13 September – 30 June 2002. Line shadows represent 95% CIs. There were 515/24 478 (2.1%), 188/9692 (1.9%) and 349/16 791 (2.1%) cases among participants in the 11 September or dust cloud, 12 September and 13 September or later exposure categories, respectively. NYS, New York State; WTC, World Trade Centre.

Figure 3

Change Point Models for Incident Prostate Cancer among World Trade Centre rescue/recovery workers: 12 March 2002–31 December 2005. ”9/11” = 11 September 2001. Best-fitting models for 3a, 3b and 3c all had one change point in 2006. All analyses control for age and race/ethnicity. (c) Also controls for ever-smoking. (a) Includes the entire Combined WTC rescue/recovery cohort (n=54 394). (b, c, d) Are restricted to those who self-reported an arrival time or dust-cloud exposure at the WTC sites, were at least 30 years old when diagnosed with prostate-cancer and were not non-Hispanic American Indian race/ethnicity (n=50 961). *Arrived on morning of 11 September or self-reported dust cloud exposure. NYS, New York State.