Background Exposure to toxic airborne pollutants incurred in the aftermath of the 9/11 World Trade Centre (WTC) attacks in New York City is associated with adverse health outcomes including increased risk for some cancer sites. A possible excess of head and neck cancer (H&N-Ca) among WTC responders was observed by a physician at Clinic A that monitors WTC responders. We launched an investigation into whether the excess exists, or is the result of surveillance bias.
Methods We conducted a chart review of WTC responders attending Clinic A from 2004 through 2014 and identified thirteen patients diagnosed with H&N-Ca (ICD-9 codes 140–149.9; 160–161.9). Two reviewers abstracted demographic, cancer (e.g. site, histology, and stage), WTC exposure, and risk factor information (e.g. smoking, alcohol use). Age-specific standardised incidence rates (SIRs) were calculated using reference rates from the NJ State Cancer Registry (NJSCR). The distributions of cancer stage, laterality, site, and histology of cases were compared to those in the NJSCR.
Results All 14 cases were male; the average age was 54.7 years. Most (75%) tumours were identified subsequent to patient complaints. SIRs were elevated among all age groups but were higher and significant in the younger age groups (34–54 years: SIR = 3.98, 95% CI: 1.74, 7.88; 55–74 years: SIR = 1.14, 95% CI: 0.64, 2.37). Compared with the NJSCR H&N-Ca tumour characteristics, those of the cases did not differ by histology distribution (p-0.79) but a higher proportion originated from the tonsils and larynx (p = 0.07).
Discussion We observed a significant excess of H&N-Ca among young WTC responders. WTC responders are a highly monitored group of workers so these preliminary findings require cautious interpretation. However, our SIR is likely an underestimate because while our cases came from Clinic A, the denominator included all monitored WTC responders, who may attend other clinical sites. The investigation is ongoing.