When the heroes of the World Trade Center are diagnosed with even a common cancer, there is a natural tendency to assume that the diagnosis is the result of their service during the disaster. However, it is important to appreciate that the firefighting profession is known to be associated with higher risks of monoclonal gammopathy of undetermined significance and multiple myelomas, compared with the general population.
Given that, it would have been preferable to compare the World Trade Center–exposed populations with an equally intensively screened, age-matched cohort of firefighters from another major city.
If we apply Sir Richard Doll’s rule that a single epidemiologic study cannot be persuasive until the lower bound of the 95% confidence interval is greater than three, the relative risks in the study by Landgren and colleagues are too small to be persuasive.
The predicted increases in cancers of the prostate, thyroid, and myeloma are interesting, but these have also been previously reported in firefighters from other cities.
Despite this, we owe it to these men and women to find the truth and determine the illnesses that are associated with their service.
Otis W. Brawley, MD, is chief medical and scientific officer and executive vice president of the American Cancer Society and a professor at Emory University, Atlanta. These comments are taken from an accompanying editorial (JAMA Oncology. 2018 April 26. doi: 10.1001/jamaoncol.2018.0498.) No conflicts of interest were declared.
