Rescue workers and volunteers who responded to the World Trade Center on 9/11 demonstrated a significantly increased risk for head and neck cancers compared with the general population, according to study results published in International Journal of Cancer.
Judith Graber, PhD, associate professor at Rutgers School of Public Health and researcher at Rutgers Environmental and Occupational Health Sciences Institute, launched their study when clinicians who treat World Trade Center-exposed responders through Rutgers’ World Trade Center Health Program expressed concern about a higher-than-expected number of patients with head and neck cancers.
“The degree to which this excess [of cancers] is directly due to dust and other [World Trade Center]-related exposures is a central focus of [this] ongoing research program,” Graber told HemOnc Today.
“Increased risk for cancer from [World Trade Center]-exposures is not limited to rescue and recovery workers,” Graber added. “The New York City World Trade Center Health Registry at the Department of Health and Mental Hygiene reported increased risk for all cancer among [World Trade Center]-exposed nonrescue and recovery workers. They saw increased risk specifically for breast cancer and non-Hodgkin lymphoma.”
Prior studies have examined cancer incidence and risk among those who responded to the World Trade Center site after 9/11.
One study published last year in JAMA Oncology showed rescue and recovery workers will experience a greater cancer burden over the next 20 years than a demographically similar population. The study projected incidence of prostate cancer, thyroid cancer and melanoma among New York City Fire Department employees who worked at the World Trade Center site will exceed typical rates in the city.
A second study, also published in JAMA Oncology, showed firefighters exposed to the disaster site have demonstrated elevated incidence of monoclonal gammopathy of undetermined significance (MGUS) — a precursor to multiple myeloma — and may be at risk for developing myeloma at an earlier age.
Graber and colleagues analyzed data from 33,809 members of the World Trade Center General Responder cohort and determined 73 had been diagnosed with head and neck cancer.
Investigators compared incidence in that cohort with the expected rate based on data from the New Jersey State Cancer Registry. They used proportional hazard regression to assess the relationship between World Trade Center exposure and other sociodemographic characteristics.
Overall, Graber and colleagues identified no excess of head and neck cancer in the World Trade Center responder cohort (standardized incidence ratio [SIR] = 1; 95% CI, 0.78-1.25).
However, researchers identified a statistically significant excess of head and neck cancers between 2009 and 2012 (SIR = 1.4; 95% CI, 1.01-1.89).
Investigators identified a similar temporal patterns for HPV-related laryngeal cancer and oropharyngeal cancer, but not for non-HPV-related types.
Researchers identified a significant association between head and neck cancer incidence and increasing age (8% per year; 95% CI, 5-12) and non-Hispanic white race/ethnicity (HR = 3.51; 95% CI, 1.49-8.27). They identified a borderline association for those who reported their occupation as military or protective service compared with other occupations (HR = 1.83; 95% CI, 0.99-3.38), but the difference did not reach statistical significance..
Graber and colleagues identified several limitations of their study, including an overall small number of cases, the long latency for most cancers, and the potential for surveillance bias.
The findings support the need to further study the potentially carcinogenic effects of World Trade Center exposure in the context of other risk factors, as well as the importance of ensuring responders continue to be monitored, Graber and colleagues wrote.
“This excess occurrence of head and neck cancers is plausible [because] first responders inhaled debris clouds containing many known carcinogens,” Graber said in a press release. “In addition, these carcinogenic exposures might add to or increase the effect of known personal risk factors for some head and neck cancers, such as tobacco smoking, heavy alcohol use and oral HPV infection.”
Members of the clinical and research communities also must closely monitor risk for lung cancer among World Trade Center responders, Graber said.
“Lung cancer takes decades to develop after carcinogenic exposures so, if there is an increased risk for lung cancer from [World Trade Center] exposures, we wouldn’t expect to be seeing it yet,” Graber told HemOnc Today. – by John DeRosier
Disclosures: The authors report no relevant financial disclosures.