Occupational trichloroethylene exposure and risk of lymphatic and haematopoietic cancers: a meta-analysis

Abstract

The carcinogenic potential of trichloroethylene (TCE) continues to generate much controversy, even after the US Environmental Protection Agency raised its classification to 'carcinogenic to humans'. We conducted a meta-analysis of published cohort and case-control studies exploring occupational TCE exposure in relation to five different lymphatic and haematopoietic cancers: non-Hodgkin's lymphoma (NHL, N=24), Hodgkin's lymphoma (HL, N=13), multiple myeloma (MM, N=11), leukaemia (N=12) and chronic/small lymphocytic leukaemia (CLL/SLL, N=7). Studies published between 1950 and 2011 were identified through a PubMed Medline search. All studies included in analyses were classified as those that assessed either occupational TCE exposure specifically ('TCE-exposure' studies) or a broader classification of all chlorinated solvents ('chlorinated solvent-exposure' studies). A significantly raised summary estimate for NHL was seen for all cohort and case-control 'TCE-exposure' studies combined (N=19; relative risk (RR)=1.32, 95% CI 1.14 to 1.54; I(2)=25.20; p-heterogeneity=0.12) and for cohort 'TCE-exposure' studies (N=10; RR=1.52, 95% CI 1.29 to 1.79; I(2)=7.09; p-heterogeneity=0.63). A non-significant but raised summary estimate was seen for NHL case-control 'TCE-exposure' studies. No significant association with NHL risk was detected overall for any 'chlorinated solvent-exposure' studies. Summary estimates for occupational TCE exposure were not associated with risk of HL, MM, leukaemia or CLL/SLL. Our updated meta-analysis of NHL, which incorporates new analytical results from three cohort and four case-control studies, supports an association between occupational TCE exposure and NHL.

Medical History, Lifestyle, Family History, and Occupational Risk Factors for Peripheral T-Cell Lymphomas: The InterLymph Non-Hodgkin Lymphoma Subtypes Project

“…Based on our data, we observed an increase in risk of PTCL and, specifically, ALCL, for textile workers. Exposures related to textile work include: dust, endotoxin (a bacterial contaminant of raw cotton fiber and cotton dust), assorted dyes, and chemicals such as trichloroethylene, which has previously been linked to lymphoma risk (33)(34)(35)(36)(37)(38). We also report that electrical fitters had increased odds of developing ALCL and angioimmunoblastic lymphoma.…”

Risk Factors for Multiple Myeloma: A Systematic Review of Meta-Analyses

“…Karami 2013 41 Epidemiologic cohort or caseecontrol studies that presented RR estimates for International Classification of Diseases codes that corresponded to MM or leukemia or with data that allowed for the calculation of RRs for a TCE-exposed worker population (eg, TCE used as a solvent among aircraft maintenance workers) were included. Ecological studies of TCE in community drinking-water because study design issues limit their use for making causal inferences were excluded.…”

NIOSH skin notation (SK) profile: trichloroethylene (TCE) [CAS No. 79-01-6].

“…Routes of exposure were unknown for these studies and cases were likely exposed via multiple routes. These authors reported a significantly raised summary estimate of non-Hodgkin's lymphoma (relative risk=1.93; CI: 1.14 to 1.54) for all cohort and case-control studies [Karami et al 2013]. Table 2 …”

“…inhalation, dermal, oral) is unknown [Hansen et al 2013;Karami et al 2013]. Hansen et al [2013] found increased liver cancer 1.93 times more likely (confidence interval [CI] 1.19 to 2.95) and cervical cancer 2.31 times more likely (CI: 1.32 to 3.75) in workers exposed to TCE; however, exposure routes are unknown and were likely a combination of multiple routes (inhalation and dermal).…”

“…Hansen et al [2013] found increased liver cancer 1.93 times more likely (confidence interval [CI] 1.19 to 2.95) and cervical cancer 2.31 times more likely (CI: 1.32 to 3.75) in workers exposed to TCE; however, exposure routes are unknown and were likely a combination of multiple routes (inhalation and dermal). Karami et al [2013] conducted a metaanalysis of published cohort and case control studies that assessed occupational exposure to TCE and five different cancers: non-Hodgkin's lymphoma, Hodgkin's lymphoma, multiple myeloma, leukemia, and chronic/small lymphocytic leukemia. Routes of exposure were unknown for these studies and cases were likely exposed via multiple routes.…”