Increased Incidence of Thyroid Cancer among World Trade Center First Responders: A Descriptive Epidemiological Assessment

Abstract

An increased incidence of thyroid cancer among 9/11 rescue workers has been reported, the etiology of which remains unclear but which may, at least partly, be the result of the increased medical surveillance this group undergoes. This study aimed to investigate thyroid cancer in World Trade Center (WTC) responders by looking at the demographic data and questionnaire responses of thyroid cancer cases from the Mount Sinai WTC Health Program (WTCHP). WTCHP thyroid cancer tumors were of a similar size (p = 0.4), and were diagnosed at a similar age (p = 0.2) compared to a subset of thyroid cancer cases treated at Mount Sinai without WTC exposure. These results do not support the surveillance bias hypothesis, under which smaller tumors are expected to be diagnosed at earlier ages. WTCHP thyroid cancer cases also reported a past history of radiation exposure and a family history of thyroid conditions at lower rates than expected, with higher than expected rates of previous cancer diagnoses, family histories of other cancers, and high Body Mass Indexes (BMIs). Further research is needed to better understand the underlying risk factors that may play a role in the development of thyroid cancer in this group.

Characteristics of Cancer Patients in the World Trade Center Environmental Health Center

“…Our distribution of cancers is likely influenced by the large number of women in the WTC EHC, which is in contrast to the predominantly male responder programs. Among men, prostate and lymphoid and hematopoietic tissue cancers were the most common cancers in the WTC EHC, similar to that described for the predominantly male rescue and recovery workers [ 7 , 22 , 23 , 24 , 25 , 26 , 37 ].…”

“…Individuals can enroll in both the WTC Health Registry (HR) and WTC EHC. There have been reports about WTC-related cancers from FDNY and other WTC responder programs as well as cancers in affected community members by the WTC Health Registry [ 2 , 7 , 21 , 22 , 23 , 24 , 25 , 26 ]. However, there has been no formal reports describing cancers at the WTC EHC.…”

Thyroid cancer among patients with thyroid nodules in Yemen: a three-year retrospective study in a tertiary center and a specialty clinic

“…The war started in Yemen in 2015 with increased bombing in many areas of the country. This could be a source of environmental carcinogens causing an increase in the rate of thyroid cancer, including an increase in the risk of FTC; this has to be further studied, but environmental pollutants have been linked to an increase in thyroid cancer [25,26].…”

World Trade Center Health Program: First Decade of Research

“…Consequentially, cancer research accounts for a large portion (21%) of the funds awarded. There are descriptive and analytic studies examining cancer mortality and incidence, with a few studies examining mechanisms or treatment [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ]. There are also notable reviews [ 77 , 78 ].…”

“…For example, the observed increased rates of thyroid cancer, a disease with few known risk factors and none seemingly connected to WTC exposure, may be caused by heightened medical surveillance rather than exposure-related disease [ 73 ]. Yet others argue against a surveillance bias in thyroid cancer findings [ 68 , 69 ]. Additional research accounting for potential biases is needed.…”