As we approach the tenth anniversary of the September 11 attacks, a new study published earlier today in The Lancet reviews cancer incidence and its potential association with exposure in firefighters in the first seven years after the attacks of 9/11 on the World Trade Center (WTC). The researchers found a modest increase in cancer cases in firefighters exposed to dust and fumes from the WTC, however they remain cautious in their interpretation of the finding because the time since 9/11 is short for cancer outcomes, and the reported excess of cancers was not limited to specific organ types. They say they cannot rule out the possibility that effects in the exposed group might be due to unidentified factors, and say longer term follow-up should include cancer screening and prevention strategies for those exposed to the WTC disaster.
Here is what Michael J. Thun, M.D., vice president emeritus, Epidemiology and Surveillance Research, said after reviewing the study:
This is a careful and thoughtful analysis that addresses the concern that the complex mix of toxicants to which rescue and recovery workers were exposed might have accelerated the development of certain cancers, so that these workers might be experiencing increased risk even within this relatively short follow-up period.
The study did find a “modest excess” of cancers being diagnosed during the years after 9/11 than among these same workers before 9/11. Their risk was about 30 percent higher when the whole follow-up period was considered and about 19 percent higher when the first two years of follow-up were excluded to eliminate increased detection from greater medical monitoring conducted by the fire department after 9/11.
- Interpretation of these findings is complicated in that most of the excess diagnoses involved cancer sites that are affected by screening (prostate, melanoma, thyroid, colon), and the study could not control for increased screening conducted outside the fire department.
While not definitive, the study provides an excellent baseline for continuing medical monitoring of these firefighters. Long term follow-up that includes screening and cancer prevention strategies will be essential.