The study, which appears in a special 9/11 issue of The Lancet, examined 9,853 firefighters, including those exposed to the WTC conditions on Sept. 11, 2001, as well as those who were not.
According to senior author David Prezant, M.D., professor of medicine at Albert Einstein College of Medicine of Yeshiva University, and his coauthors, about 12,500 Fire Department of the City of New York (FDNY) firefighters were exposed to potentially hazardous aerosolized dust on 9/11. This dust consisted of pulverized cement, glass fibers, asbestos, lead, polycyclic aromatic hydrocarbons, polychlorinated biphenyls and polychlorinated furans and dioxins produced as combustion byproducts from the collapsed and burning buildings. Firefighters also were exposed to potentially toxic fumes from burning jet fuel and from diesel smoke emitted by heavy equipment during the 10-month recovery effort.
Comparing Cancer Rates
Researchers accessed the health records for all firefighters in the study dating back to 1996, which were available as part of FDNY’s rigorous health registry. They then compared the cancer incidence rates in WTC-exposed firefighters with cancer incidence in non-exposed firefighters, as well as with a sample of people selected from the U.S. National Cancer Institute’s Surveillance Epidemiology and End Results (SEER) database who were similar in age, race and ethnic origin to the firefighters.
WTC-exposed firefighters were found to have up to a 10-percent increased risk for all cancers combined when compared to the general population sample. When the same comparison was made between WTC-exposed and non-exposed FDNY firefighters, the cancer risk for the exposed firefighters (adjusted for surveillance bias) was at least 19 percent increased, based on an excess of 38 cancer cases among the WTC-exposed firefighters.
Prezant called the finding surprising due to the short latency period but “biologically plausible” because WTC exposure included the known carcinogens polycyclic aromatic hydrocarbons, polychlorinated biphenyls and dioxins. He noted that WTC exposure also caused chronic inflammation, which “has been implicated as a risk factor for cancer in experimental and epidemiological studies.”
Prezant, who is also an attending physician in the pulmonary medicine division at Montefiore, the University Hospital and academic medical center for Einstein, and chief medical officer of FDNY, added that the results “support the need to continue monitoring firefighters and others who responded to the World Trade Center disaster or participated in recovery and cleanup at the site. This monitoring should include cancer screening and efforts to prevent cancer from developing in exposed individuals.”