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Desk study on prostate cancer and pesticide exposure - PS2609

It is proposed to review the epidemiological studies of workers involved in pesticide manufacture in order to identify any associations between specific chemical groups of pesticides and prostate cancer. The work will involve first identifying published studies of pesticide production workers and then systematically reviewing each of the studies in detail to determine the strength of evidence for or against a relationship between pesticide exposure and prostate cancer in each study. The detailed reviews will consider issues such as the size of the study population, the nature and extent of pesticide exposure and how well exposure has been characterised, potential exposure to other carcinogens or other factors influencing cancer risk, the health endpoints considered and the length of follow-up time. It is important, for example, that negative results in studies with inadequate follow-up or positive results in studies where workers were exposed to other carcinogens are not given undue importance in the overall assessment of cancer risk.

Pesticides include a very wide range of chemicals and in order to better understand any potential relationship with prostate cancer, the available studies will be organised into chemically related groups of pesticides, as it is highly unlikely that all pesticides will be associated with an equivalent prostate cancer risk. An assessment will then be made of the strength of evidence linking each group of pesticides to prostate cancer. A statistical meta-analysis will form an important part of this assessment for groups of pesticides for which multiple studies are available. It is anticipated, however, that for many types of pesticide, insufficient studies or adequate quality will exist to enable such an analysis to be undertaken.
The demonstration of a statistical relationship between prostate cancer and pesticide exposure in epidemiological studies would not necessarily mean that the relationship is causal, particularly if only a single study is available for a particular chemical class of pesticides. An important component of this study will be the follow-on investigation of the biological plausibility of any epidemiological relationships found between specific chemical groups of pesticides and prostate cancer. This will include reviewing any available data from animal and cell experiments for individual pesticides to determine whether experimental data are indicative of carcinogenicity or genotoxicity, and whether any of these data indicate a specific relationship with the prostate. In addition, given that prostate activity is endocrine controlled and the prostate is rich in enzymatic activity, consideration will be given to the potential role of pesticides in causing endocrine disruption or effects on enzyme activity in the prostate. This will include reviewing the similarity of the chemical structure of pesticides to key hormones and/or enzymes, any evidence that individual pesticides show endocrine activity in experimental systems and the role of endocrine disruption or enzyme interference in the development of prostate cancer.

The overall outcome of the review will include an assessment of the strength of evidence linking individual chemical groups of pesticides to prostate cancer, identification of key gaps in the knowledge base and recommendations as to the further research required to fill these gaps.
1.Identification of published epidemiological studies of personnel working in pesticide manufacture relevant to determining the existence, if any, of a relationship between pesticide exposure and prostate cancer;

2.Review of the strength of evidence linking pesticide manufacture to prostate cancer in individual studies;

3.If sufficient data exist, identify specific pesticides or groups of chemically related pesticides that may be linked to prostate cancer;

4.For chemically related pesticides for which more than one study of manufacturing workers is available, undertake meta-analyses to determine the overall strength of evidence linking that group of pesticides to prostate cancer;

5.Review the biological plausibility of any apparent relationships between prostate cancer and specific pesticides/class of pesticides;

6.Advise on the current strength of evidence linking pesticide exposure in pesticide manufacturing workers to prostate cancer;

7.Identify the major gaps in the existing knowledge base and make recommendations on the research required to fill these gaps and how this research might be performed.
Project Documents
• Final Report : Desk study on prostate cancer and pesticide exposure   (994k)
Time-Scale and Cost
From: 2005

To: 2006

Cost: £24,109
Contractor / Funded Organisations
Institute of Occupational Medicine
Hazardous substances              
Health Effects              
Pesticide use              
Public Health              
Toxic Substances              
Fields of Study
Pesticide Safety