Era Heath has extensive experience in the investigation of ‘cancer clusters’ in the work place and was involved in the highly publicized analysis of brain tumours at RMIT University in Melbourne.

The investigations are undertaken by very experienced occupational and forensic physicians with the assistance of hygienists and environmental scientists.

The protocol recommended by the United States National Institute of Occupational Safety and Health (NIOSH) for investigating clusters (http://www.cdc.gov/niosh/topics/cancer/) is followed.

NIOSH has developed an approach to the analysis of a suspected cancer cluster to determine its relationship to a postulated environmental exposure. This approach involves a four-way analysis consisting of:-

  • A statistical analysis in which the observed cancer rates (cases per 100,000) are compared with the expected rates (from the state cancer registry) to determine if there is an excess. In addition, this company includes an analysis of the relationship of time worked in the specific location to the incidence of the cancer occurring.
  • A determination of the type of tumors in the cluster because the consistency of the type of tumors found in a cluster is a pointer to a common exposure. The World Health Organisation classification of tumors is used.
  • It is inappropriate to determine the existence of a potential cluster by one criterion alone. The NIOSH method enables due consideration to be given to all four criteria thus enhancing the accuracy of the investigation. From experience, Southern Medical Services prefers to manage all aspects of the investigation to contain costs and ensure that environmental investigations are appropriately undertaken.

 

  • A consideration of the latency periods for cancer development. The time between first exposure to a (putative) cancer-causing agent and clinical recognition of the disease is called the latency period. Typically it is 10-20 years and helps gauge plausibility of a putative causal exposure.

An environmental study where agents which are known to cause cancers or are suspected to cause cancers are sought as their presence may indicate a causal relationship. Related to this is the exposure period which is the duration of time in which a case was exposed to putative agents. This also helps gauge plausibility of a causal exposure because dose is a function of exposure duration times concentration.