WTC workers show higher incidence of prostate Ca

Among rescue and recovery workers exposed to dust, debris, and fumes following the World Trade Center terrorist attack, there was an increased incidence of prostate and thyroid cancers and multiple myeloma, although it is not clear how big a factor medical screening and non-WTC risk factors contributed to these increases, according to a recent study.

The authors, who published their findings in JAMA (2012; 308:2479-88), did not find a statistically significant increased incidence for all cancer sites combined, and note that the findings on the three cancers that did increase should be viewed with caution for several reasons, including that they were based on a small number of cancers, multiple comparisons, and a relatively short follow-up time.

First author Jiehui Li, MBBS, MSc, of the New York City Department of Health and Mental Hygiene, Long Island City, NY, and colleagues evaluated cancer incidence among WTC rescue/recovery workers and volunteers and those not involved with rescue/recovery work. The observational study included 55,778 New York State residents enrolled in the World Trade Center Health Registry in 2003-2004, including 21,850 rescue/recovery workers and 33,928 individuals not involved in rescue/recovery, who were followed up from enrollment through December 2008. Within-group comparisons using various models also assessed the relationship between intensity of World Trade Center exposure and selected cancers.

For all sites combined, cancer incidence was not significantly different from that in the reference population during either the early period (enrollment through 2006) or the later period (2007-2008). The authors found that of the 23 cancer sites investigated, three had significantly elevated incidence during the later period: prostate (n=67; standardized incidence ratio, 1.43 [95% CI, 1.11-1.82]; RD, 61 [95% CI, 20.1-91.4] per 100,000 person-years), thyroid (n = 13; SIR, 2.02 [95% CI, 1.07-3.45]; RD, 16 [95% CI, 2.1-22.6] per 100,000 person-years), and multiple myeloma (n=7; SIR, 2.85 [95% CI, 1.15-5.88]; RD, 11.1 [95% CI, 2.2-14.2] per 100 000 person-years). Of these three, thyroid cancer also was significantly elevated during the early period.

"Given the relatively short follow-up time and lack of data on medical screening and other risk factors, the increase in prostate and thyroid cancers and multiple myeloma should be interpreted with caution. The etiological role of WTC exposures in these three cancers is unclear. Longer follow-up of rescue/recovery workers and participants not involved in rescue/recovery is needed with attention to selected cancer sites and to examine risk for cancers with typically long latency periods," the authors wrote.