A Case-Cohort Study of Hematopoietic Malignancies and Related Disorders and Lung Cancer in Benzene-Exposed Workers in China

May 11, 2021 updated by: National Cancer Institute (NCI)

A Case - Cohort Study of Hematopoietic Malignancies and Related Disorders and Lung Cancer in Benzene-Exposed Workers in China

This study will examine the risks of workplace exposure to benzene, a substance known to lead to cancer of the blood and possibly of the lungs. It is used widely in industries and is a contaminant in the environment. Researchers from the National Cancer Institute and the China Center for Disease Control (formerly Chinese Academy of Preventive Medicine) had done previous studies of workers in manufacturing industries in China of people who worked at least 1 day from 1972 to 1987 in 12 cities in that country. Data were collected of approximately 75,000 workers exposed to benzene and 35,000 who were not, with the purpose of investigating the relationship between benzene exposure and cancer risk. For workers exposed to benzene, there was a significant risk of cancer affecting the blood cells and a 1.8-fold excess of lung cancer among them. This study will expand those findings and also identify the effects of benzene amounts and whether there is a genetic tendency for benzene poisoning. About 3,860 benzene-exposed workers from the 12 cities will be interviewed. Next-of-kin of deceased workers, and a subcohort (additional grouping) of participants will serve as a control group in the research.

Patients who have worked at places where there was exposure to benzene will have a brief physical exam and samples of cells from a mouth rinse and samples from blood will be collected to study the genetic influence on developing blood diseases from workplace exposures.

All participants or next-of-kin, for deceased, will be given a questionnaire about their work history, use of cigarettes and hair dyes, medications they take, and family history of cancer. Interviews of about 40 minutes long will be conducted at participants homes or workplaces, at a time convenient to them, and the interviews will be audiotaped.

Study Overview

Status

Completed

Conditions

Detailed Description

Benzene is a known leukemogen and may cause lymphoma as well, but its ability to , cause these conditions below 10 parts per million (ppm) in air are unclear. It is currently regulated in the United States at 1 ppm as an 8-hour time-weighted average and at a 5 ppm short-term exposure level for 15 minutes. There is a critical need to assess risks related to benzene exposure under 10 ppm because it is widely used industrially and a ubiquitous contaminant in the environment.

The National Cancer Institute (NCI) and the Chinese Academy of Preventive Medicine (CAPM), whose name was recently changed to the China Center for Disease Control (CDC) previously established a cohort of 75,000 workers exposed to benzene in 12 cities in China and 35,000 unexposed comparison workers, to investigate the relationship between benzene exposure and cancer risk, from 1972 to 1987. We followed up each worker using factory records and reported results suggesting that benzene exposure under 10 ppm may be associated with increased risk of acute non-lymphocytic cancer and could also be associated with increased risk of lymphoma and lung cancer. We have now laid the groundwork for a further epidemiologic investigation in China to evaluate health risks from lower levels of benzene exposure, particularly as present in the factories during the 1990s. The cohort was followed up through 1999, and through this effort we have identified 3260 subjects for study, including cases (HLD malignancies, n= 161; benzene poisoning, n= 1040; lung cancer, n= 560) and 1500 subjects in a cohort sub-sample to be used as the comparison group. In addition, we have identified a series of cases with benzene poisoning and controls from the same factories outside of the cohort (n = 600).

We propose to contact next-of-kin of deceased subjects (essentially all cancer cases and some members of the sub-cohort are deceased), for questionnaire-based evaluation of benzene and other exposures, and to contact living subjects (primarily the benzene poisoning cases and the sub-cohort sample) for collection of questionnaires and biologic samples. The questionnaires (formatted for direct interview of living subjects or for next-of-kin) will collect information on potential confounders needed in the analysis of benzene's effects and information on work experience outside of the study cohort factories. The biologic sample collection (13 ml blood and buccal cell rinse) will provide material primarily for study of genetic polymorphisms potentially associated with benzene metabolism and disease status. The polymorphisms being studied are relatively common in the Chinese population and may be associated with a relatively modest increase in risk (1.5 to 2-fold). Written informed consent will be obtained from all next-of-kin and all live study subjects. We will attempt to enroll 3,860 study subjects or next-of-kin. The study will be carried out with Drs. Gui-Lan Li and Song-Nian Yin and colleagues from the China CDC, Beijing, China.

Study Type

Observational

Enrollment (Actual)

3260

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
      • Beijing, China
        • China Center for Disease Control (CDC)

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

21 years to 90 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

From a cohort of 74,827 benzene-exposed and 35,804 unexposed workers employed (Bullet) one month in several industries and followed up during 1972-99, we identified a case-cohort population that included incident and deceased cases with hematopoietic malignancies diagnosed during those same years among exposed and unexposed workers and a 1,500 worker subcohort (1,100 exposed, 400 unexposed). The subcohort was selected by stratified random sampling (by sex, exposure status, and age at start of follow-up) from 106,641 of the cohort members. Other outcomes to be evaluated include incident cases with benzene hematotoxicity and deaths from lung cancer.

Description

  • INCLUSION CRITERIA:

The study subjects are Chinese. Gender is not an important consideration as a risk factor in benzene-exposed workers. Subjects will be recruited by on - site collaborators in each of the 12 study cities. Participation is voluntary. Subjects may withdra from the study at any time.

EXCLUSION CRITERIA:

Based on the available data, no cases (an , thus no controls) will be less than 18 years of age. Any subject under 18 would be excluded from the study. Otherwise, no exclusions of potential study subjects are planned.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Benzene Cohort
Benzene exposed and unexposed workers.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Benzene poisoning, Hemapoietic Malignancies and related disorders, Lung cancer
Time Frame: 1972-1999
Benzene poisoning, Hemapoietic Malignancies and related disorders, Lung cancer
1972-1999

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Cancer Institute (NCI)

Collaborators

China for Disease Control (CDC)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ACTUAL)

July 11, 2006

Primary Completion (ACTUAL)

December 31, 2016

Study Completion (ACTUAL)

November 6, 2020

Study Registration Dates

First Submitted

November 15, 2007

First Submitted That Met QC Criteria

November 15, 2007

First Posted (ESTIMATE)

November 16, 2007

Study Record Updates

Last Update Posted (ACTUAL)

May 12, 2021

Last Update Submitted That Met QC Criteria

May 11, 2021

Last Verified

November 1, 2020

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 999906205
  • 06-C-N205

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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