As we near 2 decades since the terrorist attack of 9/11, many of our memories, feelings, and worries of that tragedy have faded, our thoughts drifting to other causes, other cares, other grave calamities. But there is still a group of people whose memories are as vivid, whose feelings are as raw, and whose concerns are as overwhelming today as that fateful day: these people are the men and women who were the first responders and survivors of that tragic day. They live with not only agonizing memories, feelings and worries, but also the health problems related to 9/11. One of these health issues is cancer.
On and after 9/11, the responders and survivors of the World Trade Center disaster were exposed to a variety of carcinogens: asbestos, silica, polycyclic aromatic hydrocarbons, benzene, and heavy metals. After the collapse of the two office towers, those at Ground Zero endured the highest exposure to carcinogens; and following this acute exposure, many underwent protracted exposure during terminal cleanup that ended in July 2002.
In 2011, Owens et al reported a modest increase in cancer for New York City firefighters who were involved in the World Trade Center attacks (Lancet 2011;378(9794):898-905). Two years later, in 2013, Solan et al published a study on the incidence of cancer in responders between 2001 and 2008 and noted a 15 percent increase for all cancer sites combined; those with the highest exposure showed the highest risk of cancer (Environ Health Perspect 2013;121(6):699-704).
Then in 2016, Li et al studied the incidence of cancer in responders and survivors 10 years after 9/11; they detected an increased incidence in the number and types of cancer for both first responders and survivors (Am J Ind Med 2016;59(9):709-721). First responders developed cancer at a rate of 11 percent higher than the control group; and survivor cancer rate was 8 percent higher. The incidence of specific cancers was also elevated in the responder and survivor populations: both populations had a higher incidence of prostate and skin melanoma; first responders had a higher incidence of thyroid cancer; and survivors had a higher incidence of breast and non-Hodgkin's lymphoma. But all three of these studies should be interpreted with caution.
This caution is warranted given the complexity of tumorigenesis and the number of variables in the exposed population. In most cases, tumorigenesis occurs over decades and involves multiple mutations, so interpreting data after 10 years maybe be premature. Other variables that may confound the data are the level of carcinogen exposure during 9/11 and exposure to carcinogen before 9/11; and when many of those exposed to the highest levels were responders, it's challenging to identify a control group because responders usually have better fitness level than their peers. In addition to these limitations, the results of these studies could be biased because the exposed group received—and continues to receive—more monitoring, more screening, and advanced diagnostic imaging.
But Tuminello et al completed a study that refuted a monitoring and screening bias for thyroid cancer (Int J Environ Res Public Health 2019; doi: 10.3390/ijerph16071258). Another study looked at the incident of thyroid cancers in this population and concluded the higher incidence of thyroid cancer was not an artifact of increased screen but of actual increase in number of cases (Int J Environ Res Public Health 2019;16(9):1600). This study showed there wasn't an increase in diagnosis of benign thyroid cancers or false-positives, and the possibility of surveillance was also negated because of the control group's demographics and tumor characteristics were closely matched to the exposure group. Studies are continuing to evaluate many of these complicating factors and to determine the relationship between exposure and cancer.
Much of the research in this area is being conducted by the World Trade Center (WTC) Health Program. Research supported by the WTC Health Program focuses on these six sectors:
- biomarkers of exposures or health outcomes;
- exposure-response relationships;
- improvements in diagnosis and treatment;
- patterns of illness (age, gender, etc.);
- risk factors for disease; and
- other research studies on WTC-related health conditions or emerging conditions.
The WTC Health Program, which the Center for Disease Control and Prevention oversees, supports not only research but also provides health care services for those affected by the 9/11 terrorist attacks in New York, the Pentagon, and Shanksville, Pa. For care, the WTC Health Program offers multiple Clinical Centers of Excellence throughout the New York metropolitan area, and there is a Nationwide Provider Network that provides care for members outside of the NY metropolitan area. Individuals involved in the events of 9/11 should refer to the WTC Health Program to help determine eligibility and, if qualified, become part of the program's registry. Patients enrolled in the program are eligible for health care treatment, including prescription benefits.
The program tracks, monitors, and treats registered people who develop health conditions related to exposure to hazardous material related to 9/11, such as asthma, gastroesophageal reflux disease, post-traumatic stress, and cancer. The program covers people with cancer under the age of 20, over 300 common cancers, and numerous rare cancers. The 15 most common cancers in the program are the following: non-melanoma skin, prostate, female breast, melanoma of skin, lymphoma, thyroid, lung, kidney, leukemia, skin-carcinoma in situ, colon, bladder, myeloma, oropharynx, and rectum tonsil.
At the end of September 2019, 99,769 people (76,904 responders and 22,865 survivors) had enrolled in the WTC Health Program. The largest percentage of enrollees are males (79%), general responders (59%), ages 55-64 (35%). And most enrollees live in the state of New York. Of all enrollees, 14,755 (9,967 responders and 4,788 survivors) are receiving care for cancer, and 788 enrollees have died from cancer. The top three cancers for responders (in order of highest to lowest): non-melanoma skin, prostate, and melanoma skin; the top three cancers for survivors (in order of highest to lowest): prostate, female breast, and non-melanoma skin.
As time passes, more people enroll in the program, and research data matures, it will become clearer to what extent exposure to the carcinogens of 9/11 contributed to the incidence of cancer; but right now, many of these factors remain unsettled. Some unsettled questions are whether the incident of all cancers will increase or only specific subsets; whether new mutations and, therefore, new drivers will emerge for these cancers; and whether these cancers will respond differently to available treatments. All these and many more questions remain unknown, but with the support of the WTC Health Program, data are being collected and researched to solve these questions.
Vincent Vidaurri is a contributing writer.