9/11 firefighters at greater risk of cancer

By Dr. Ananya Mandal, MDSep 2 2011

A new study shows that firefighters who were exposed to toxic dust and fumes clogging the air after the World Trade Center towers collapsed 10 years ago are more likely to develop cancer.

When compared with firefighters who did not work at ‘ground zero’, firefighters working the pile were 19% more likely to get a cancer diagnosis says the study. According to the research, published Thursday in the Lancet medical journal, the increase occurred during the first seven years after 9/11.

Dr. David Prezant, chief medical officer at the New York City Fire Department and the study's lead author, said, “We excluded cancers that might have been diagnosed early (that may have existed before the attack) ... and we still see a 19% increase…When we put those cancers back in, we see a 32% increase.”

There were 263 firemen at Ground Zero who were diagnosed with cancer in the first seven years after Sept. 11, 2011. This is more than would be expected in the general population of same-aged men, and more than what is seen among firefighters who were not at the disaster site.

It is an unexpected finding considering that for most cancers, the latency period -- the time between exposure to a carcinogen and expression of disease he added. “My initial bias was that for the first 10 or 15 years we would not see an increase,” said Prezant. “That's another reason I think our findings are so strong, because I actually thought we would find the opposite.”

One theory about how cancer might develop so soon among responders is that the unique characteristics of ground zero dust, and the sheer number of chemicals contained in it, may have accelerated disease in responders. “Typically for solid tumors we would say there's a latency period of decades,” said Dr. Jacqueline Moline, author of a study about multiple myeloma among responders. “Is something about the dust accelerating things much sooner than we would have expected?”

Potential cancer-causing agents such as asbestos that coated the Trade Center buildings' lower columns, and benzene, a component of jet fuel that caused uncontrollable fires when planes barrelled into the twin towers, have been a cancer concern for researchers. So have the high volume of particulates and gases inhaled by firefighters, said Prezant. “Those particulates are not just dust, they are dust coated with the same chemicals that were in the air in terms of the gases, sometimes, actually, getting deeper into the lung or better penetrating into the blood circulation because they're carried on a particle,” said Prezant, who is also a pulmonologist with the FDNY.

Moline wrote one of the only other papers -- a small case series published in 2009 -- suggesting increased cancer risk among responders. It found a small but inordinate number of multiple myeloma cases among responders under age 45. Multiple myeloma is a blood cancer that typically strikes much later in life. “Because we're dealing with unprecedented exposures, we need to be vigilant and do regular follow-up of this type of study to see if this effect is changed over time,” said Moline, the chair of the Department of Population Health at Northshore LIJ Health System. “The question always is, are we seeing some cancers younger ... that you might not expect if (the risk of a particular cancer) increases with age?”

This is an early study that will require several years of follow-up, said Prezant. “We've just begun to understand what's happening after the World Trade Center,” said Prezant. “We may find that some of our conclusions change over time, get stronger or change entirely.”

The study only looked at male firefighters. It did not include other groups of people who were also exposed. It also only tracked firemen for seven years. This may not be long enough to get a firm handle on any potential increased risk for cancer, the researchers say.

The second Lancet study included 27, 449 people who took part in the WTC Medical Monitoring and Treatment Program.

Another study shows that rescue and recovery workers are still experiencing breathing issues and mental health problems one decade after exposure to the toxic dust and debris at Ground Zero. After nine years, rescue and recovery workers are at risk for asthma, chronic sinus infection, acid reflux or heart burn, depression, anxiety, panic attacks, Post-traumatic stress disorder (PTSD) etc.

Prezant's study was funded by the U.S. National Institute for Occupational Safety and Health.