title: Early assessment of cancer outcomes in New York City firefighters after the 9/11 attacks: an observational cohort study.
abstract: BACKGROUND
  The attacks on the World Trade Center (WTC) on Sept 11, 2001 (9/11) created the potential for occupational exposure to known and suspected carcinogens. We examined cancer incidence and its potential association with exposure in the first 7 years after 9/11 in firefighters with health information before 9/11 and minimal loss to follow-up.
  
  
  METHODS
  We assessed 9853 men who were employed as firefighters on Jan 1, 1996. On and after 9/11, person-time for 8927 firefighters was classified as WTC-exposed; all person-time before 9/11, and person-time after 9/11 for 926 non-WTC-exposed firefighters, was classified as non-WTC exposed. Cancer cases were confirmed by matches with state tumour registries or through appropriate documentation. We estimated the ratio of incidence rates in WTC-exposed firefighters to non-exposed firefighters, adjusted for age, race and ethnic origin, and secular trends, with the US National Cancer Institute Surveillance Epidemiology and End Results (SEER) reference population. CIs were estimated with overdispersed Poisson models. Additional analyses included corrections for potential surveillance bias and modified cohort inclusion criteria.
  
  
  RESULTS
  Compared with the general male population in the USA with a similar demographic mix, the standardised incidence ratios (SIRs) of the cancer incidence in WTC-exposed firefighters was 1·10 (95% CI 0·98-1·25). When compared with non-exposed firefighters, the SIR of cancer incidence in WTC-exposed firefighters was 1·19 (95% CI 0·96-1·47) corrected for possible surveillance bias and 1·32 (1·07-1·62) without correction for surveillance bias. Secondary analyses showed similar effect sizes.
  
  
  CONCLUSIONS
  We reported a modest excess of cancer cases in the WTC-exposed cohort. We remain cautious in our interpretation of this finding because the time since 9/11 is short for cancer outcomes, and the reported excess of cancers is not limited to specific organ types. As in any observational study, we cannot rule out the possibility that effects in the exposed group might be due to unidentified confounders. Continued follow-up will be important and should include cancer screening and prevention strategies.
  
  
  BACKGROUND
  National Institute for Occupational Safety and Health.
authors: Department of Medicine, Albert Einstein College of Medicine Montefiore Medical Center, Bronx, NY, USA.
authors: Rachel
authors: R
authors: Zeig-Owens
authors: Mayris P
authors: MP
authors: Webber
authors: Charles B
authors: CB
authors: Hall
authors: Theresa
authors: T
authors: Schwartz
authors: Nadia
authors: N
authors: Jaber
authors: Jessica
authors: J
authors: Weakley
authors: Thomas E
authors: TE
authors: Rohan
authors: Hillel W
authors: HW
authors: Cohen
authors: Olga
authors: O
authors: Derman
authors: Thomas K
authors: TK
authors: Aldrich
authors: Kerry
authors: K
authors: Kelly
authors: David J
authors: DJ
authors: Prezant
mesh_terms: D000328:Adult; D002273:Carcinogens; D015331:Cohort Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D009519:New York City / Q000453:epidemiology; D016273:Occupational Exposure; D018635:Rescue Work / Q000706:statistics & numerical data*; D047851:September 11 Terrorist Attacks / Q000706:statistics & numerical data*
chemical_list: D002273:Carcinogens