Multiple myeloma and its precursor disease among firefighters exposed to theworld trade center disaster

IMPORTANCE The World Trade Center (WTC) attacks on September 11, 2001, created an unprecedented environmental exposure to known and suspected carcinogens suggested to increase the risk of multiplemyeloma. Multiplemyeloma is consistently preceded by the precursor states of monoclonal gammopathy of undetermined significance (MGUS) and light-chain MGUS, detectable in peripheral blood. OBJECTIVE To characterize WTC-exposed firefighters with a diagnosis of multiplemyeloma and to conduct a screening study for MGUS and light-chain MGUS. DESIGN, SETTING, AND PARTICIPANTS Case series of multiplemyeloma in firefighters diagnosed between September 11, 2001, and July 1, 2017, together with a seroprevalence study of MGUS in serum samples collected from Fire Department of the City of New York (FDNY) firefighters between December 2013 and October 2015. Participants included all WTC-exposed FDNY white, male firefighters with a confirmed physician diagnosis of multiple myeloma (n = 16) andWTC-exposed FDNY white male firefighters older than 50 years with available serum samples (n = 781). EXPOSURES WTC exposure defined as rescue and/or recovery work at theWTC site between September 11, 2001, and July 25, 2002. MAIN OUTCOMES AND MEASURES Multiplemyeloma case information, and age-adjusted and age-specific prevalence rates for overall MGUS (ie, MGUS and light-chain MGUS), MGUS, and light-chain MGUS. RESULTS SixteenWTC-exposed white male firefighters received a diagnosis of multiple myeloma after September 11, 2001; median age at diagnosis was 57 years (interquartile range, 50-68 years). Serum/urine monoclonal protein isotype/free light-chain data were available for 14 cases; 7 (50%) had light-chain multiplemyeloma. In a subset of 7 patients, myeloma cells were assessed for CD20 expression; 5 (71%) were CD20 positive. In the screening study, we assayed peripheral blood from 781WTC-exposed firefighters. The age-standardized prevalence rate of MGUS and light-chain MGUS combined was 7.63 per 100 persons (95%CI, 5.45-9.81), 1.8-fold higher than rates from the Olmsted County, Minnesota, white male reference population (relative rate, 1.76; 95%CI, 1.34-2.29). The age-standardized prevalence rate of light-chain MGUS was more than 3-fold higher than in the same reference population (relative rate, 3.13; 95%CI, 1. 99-4.93). CONCLUSIONS AND RELEVANCE Environmental exposure to the WTC disaster site is associated with myeloma precursor disease (MGUS and light-chain MGUS) and may be a risk factor for the development of multiplemyeloma at an earlier age, particularly the light-chain subtype.