Cancer Risk At Ground Zero
It is a very emotional charged issue when discussing anything about the World Trade Center attack in 2001. In the largest cancer study of firefighters ever conducted, research published in this week's 9/11 Special Issue of The Lancet found that New York City firefighters exposed to the 9/11 World Trade Center (WTC) disaster site were at least 19 percent more likely to develop cancer in the seven years following the disaster as their non-exposed colleagues and up to 10 percent more likely to develop cancer than a similar sample from the general population. The study is the first to look at cancer rates among the all of the exposed firefighters, and the findings may help pave the way for federal health benefits for rescue workers now suffering from cancer nearly a decade after the attacks.
It is almost always impossible to prove exactly what caused a cancer in any individual, because most cancers have multiple possible causes. For example, if a person who uses tobacco heavily develops lung cancer, then it was very probably caused by the tobacco use, but since everyone has a small chance of developing lung cancer as a result of air pollution or radiation, then there is a tiny chance that the smoker's lung cancer actually developed because of air pollution or radiation.
Cancers are primarily an environmental disease with 90-95% of cases attributed to environmental factors and 5-10% due to genetics.
Some substances cause cancer primarily through their physical, rather than chemical, effects on cells.
A prominent example of this is prolonged exposure to asbestos, naturally occurring mineral fibers which are a major cause of mesothelioma, a type of lung cancer.
Nonfibrous particulate materials that cause cancer include powdered metallic cobalt and nickel, and crystalline silica (quartz, cristobalite, and tridymite).
Usually, physical carcinogens must get inside the body (such as through inhaling tiny pieces) and require years of exposure to develop cancer.
The Lancet study evaluated the health of 9,853 WTC-exposed and non-exposed firefighters over the seven years following 9/11. The senior author was David Prezant, M.D., professor of medicine at Albert Einstein College of Medicine of Yeshiva University, an attending physician in the pulmonary medicine division at Montefiore, the University Hospital and academic medical center for Einstein, and chief medical officer of the Fire Department of the City of New York (FDNY). His co-authors were from Einstein, Montefiore and FDNY.
The terrorist attacks on the WTC on September 11, 2001 created an unprecedented environmental disaster in the New York City area. Many first responders, including about 12,500 FDNY firefighters, were exposed to potentially hazardous aerosolized dust consisting 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. They were also exposed to potentially toxic fumes—initially from burning jet fuel and, during the 10-month recovery effort, from diesel smoke emitted by heavy equipment. Dr. Prezant has previously published several studies regarding the lung health of WTC-exposed first responders. The Lancet study was the first effort to assess the incidence of cancer among an entire WTC-exposed cohort in this case WTC-exposed firefighters.
The Lancet study also compared WTC-exposed and non-exposed firefighters with respect to cancer incidence at 15 specific sites in the body and found no sites for which the cancer incidence among WTC-exposed firefighters was significantly increased. However, a trend towards increased risk was noted in 10 of the 15 sites studied. The study noted that this failure to reach statistical significance may have been due to the small sample size available for these site-specific cancers. Analyses accounting for cigarette smoking status in WTC-exposed and non-exposed firefighters were similarly affected by small sample size. The authors note, however, that all nine WTC-exposed firefighters who developed lung cancer were smokers.
In explaining how exposure to WTC dust apparently led to an overall increase in cancer incidence among WTC-exposed firefighters, Dr. Prezant called the finding surprising due to the short latency period but "biologically plausible" because WTC exposure included polycyclic aromatic hydrocarbons, polychlorinated biphenyls and dioxins—all known carcinogens. He noted that WTC exposure also caused chronic inflammation and that such inflammation "has been implicated as a risk factor for cancer in experimental and epidemiological studies."
For further information: http://www.einstein.yu.edu/home/news.asp?id=703