1.1
In December 2018, reports of a possible cancer cluster on the Bellarine Peninsula in Victoria came to light through an article in The Age, which reported that a number of young people in the Bellarine area had recently died of cancer, many from blood-related cancers. This was followed by an article in the Sunday Age which discussed the possible links between cancer incidence and use of a pesticide called dieldrin.
1.2
Over the following months, multiple media articles reported young people in the Bellarine area being diagnosed and, in some cases, dying of different types of cancer.
1.3
In January 2019, the Victorian Chief Health Officer (CHO) undertook an investigation into a possible cancer cluster on the Bellarine Peninsula. The CHO’s review found no evidence of a cancer cluster. Despite this conclusion, some residents of the Bellarine Peninsula continued to raise concerns about the possibility of a cancer cluster as well as perceived higher rates of autoimmune disease in the area.
1.4
The community raised concerns about what might be the cause of a perceived higher rate of cancer on the Bellarine Peninsula. Some believe it is linked to an organochlorine pesticide (OCP) called dieldrin, previously used for agricultural purposes on the Bellarine Peninsula. Other residents are concerned that the possible cause is the chemicals used for mosquito control by the City of Greater Geelong and former local councils.
1.5
During 2019, the Victorian Department of Health and the CHO continued to respond to these concerns by convening the Potential Cancer Cluster Expert Advisory Group, engaging with the community, and commissioning the Cancer Council Victoria to conduct a more extensive epidemiological study, which also found no evidence of increased cancer rates in the Barwon Heads region.
1.6
However, some members of the Barwon Heads community remain concerned about the possibility of a cancer cluster or autoimmune disease cluster and about potential links between these diseases and certain chemicals that were historically used for mosquito control in the area.
1.7
It is in this context that Senate Community Affairs References Committee (committee) embarked on this inquiry, seeking to listen to the community’s concerns and to explore the extent and appropriateness of the investigations to date. In doing so, the committee has engaged with the community, with local and state authorities, and with medical and chemicals experts.
Structure of the report
1.8
The report consists of five chapters, including this introductory chapter:
Chapter 1 provides background information about cancer clusters, the Bellarine Peninsula and the conduct of the inquiry.
Chapter 2 explores the health concerns and possible causes raised by the Bellarine Peninsula community.
Chapter 3 examines the investigations to date into the possibility of a cancer cluster on the Bellarine Peninsula.
Chapter 4 discusses the use of chemical insecticides on the Bellarine Peninsula for mosquito control.
Chapter 5 discusses issues raised by inquiry participants about chemical insecticides and disease causation. It also considers whether any further epidemiological or exposure studies would be beneficial.
Role of the committee
1.9
The committee has been tasked by the Senate to undertake an inquiry into investigations into a possible cancer cluster on the Bellarine Peninsula, Victoria, with particular reference to:
(a)
the health concerns of local residents;
(b)
the incidence of cancer cases in the area, and any possible environmental or other contributing factors;
(c)
the evidence, approach and outcomes concerning the Victorian Chief Health Officer’s investigation of cancer rates on the Bellarine Peninsula; and
(d)
any other related matter.
1.10
The committee recognises the significant impact that cancer has on the community and acknowledges the concerns raised by residents about the incidence of cancer and autoimmune disease cases on the Bellarine Peninsula.
1.11
The committee acknowledges it does not have scientific expertise in epidemiology, toxicology or cancer causation. As such, the committee has sought evidence from a range of witnesses, including experts in cancer epidemiology and chemical carcinogens, concerned members of the public, and government agencies.
1.12
Throughout the inquiry, the committee has remained mindful that providing a forum for local residents to express their views, share concerns with others and be heard by all levels of government was central to this inquiry. An important part of the committee’s role has been to provide the community with the opportunity to reflect on the investigations previously undertaken and to suggest new ways to examine the possibility of a cancer cluster in the Bellarine Peninsula region.
Bellarine Peninsula
1.13
The Bellarine Peninsula region is located south-west of Melbourne, around 30 minutes’ drive south of Geelong. Barwon Heads lies in the Bellarine ward of the City of Greater Geelong local government area. Barwon Heads, formerly a quiet village, is now a town of almost 4,000 permanent residents, located on the west side of the Barwon River and adjacent to the town of Ocean Grove. Along with the nearby town of St Leonards, Barwon Heads was the location for the filming of the well-loved ABC television series Sea Change in the 1990s.
1.14
Barwon Heads is a popular holiday destination, with nearby beaches Raafs Beach and Thirteenth Beach and other locations for water sports including snorkelling and surfing. It hosts Parks Victoria’s Barwon Bluff Marine Sanctuary, Jirrahlinga Koala & Wildlife Sanctuary, Barwon Heads Primary School and the Bop Bop Karrong Child and Family Centre health service, and it has an active community life and a number of community organisations and sporting clubs. The town has a much bigger population during the warmer months, with some holidaymakers returning every year.
Cancer clusters
1.15
Cancer is the name of a category of around 200 different diseases, with prostate cancer, breast cancer and bowel cancer the most common types in Australia. In 2016, cancer was the leading cause of death in Australia and was the cause of around three in 10 deaths. Due to improved cancer screening, early diagnosis and treatment, survival rates have increased over time for many types of cancer. However, even for those who survive cancer, a cancer diagnosis always has a severe and lasting impact on the individual, their family and friends, and their community. Cancer has been described as ‘the most feared illness’.
1.16
The Australian National Health and Medical Research Council defines a cancer cluster as follows:
A cancer cluster is the occurrence of a greater than expected number of cancer cases within a group of people in a geographical area over a period of time. The identification of a cluster using this definition does not necessarily imply that there is a causal agent, because cancer events can occur by chance. It does, however, indicate the need to assess whether the cluster can be related to factors other than chance.
1.17
Community concern and media reports about a suspected cancer cluster can lead to formal scientific investigations by health authorities. These investigations aim to determine the actual incidence of cancer in that population—that is, whether there is a true cluster—and, in some cases, to identify whether there is a plausible cause for the cancer and reduce any risk of further harm. These kinds of investigations will be further discussed in chapter 3 of the report.
1.18
Most assessments and investigations of possible cancer clusters do not find a true statistical cluster (where the cancer incidence is greater than expected). One of the most well-known Australian cancer cluster investigations is the ‘ABC breast cancer cluster’ investigation, relating to breast cancers diagnosed in a group of ABC employees in Brisbane between 1994 and 2006. Extensive investigations into this cluster eventually established that it could be considered a true chance cluster and that the breast cancers appeared to be unrelated to each other.
1.19
An American academic scientific review of 428 investigations of suspected cancer clusters found that one in eight (72 cases, or 13 per cent) of the reported cases were true cancer clusters. Of these 72, there was only one case (0.23 per cent of the total number) where the investigation found a clear cause for the cancer. These results are consistent with the current scientific consensus that cancer cluster investigations are highly unlikely to establish a single clear cause for the cancers under investigation in that population.
1.20
This differs from investigations of suspected clusters of other diseases. For example, investigations of infectious diseases often lead to the identification of a clear cause for the disease.
1.21
A study of Australian print media and cancer cluster investigations between May 2006 and February 2008 found that 13 possible cancer clusters in workplace and community settings were identified across three states; however, this period of time also coincided with increased media coverage of cancer clusters, linked to the ABC cancer cluster in Brisbane. This study suggests that media coverage may have amplified the community’s perception of risk from suspected cancer clusters.
1.22
There is very little data available on the total number of suspected cancer clusters in Australia. Queensland Health receives around 20 inquiries about suspected cancer clusters each year. The Victorian Department of Health averages one inquiry about a suspected cancer cluster every two years.
Conduct of the inquiry
1.23
On 17 October 2019, the Senate referred an inquiry into investigations into a possible cancer cluster on the Bellarine Peninsula, Victoria to the committee for inquiry and report by 12 August 2020. The committee was granted an extension to report by 18 March 2021. The committee was granted further extensions to report by 17 June 2021, by 22 June 2021, by 24 June 2021 and by 30 June 2021.
1.24
The inquiry was advertised on the committee's website and the committee wrote to stakeholders inviting them to make submissions, to be lodged by 27 March 2020. Submissions continued to be accepted after this date. The committee received 43 submissions, which can be accessed via the committee's website.
1.25
The committee held three public hearings:
1 May 2020, Canberra, ACT
20 November 2020, Canberra, ACT
20 April 2021, Barwon Heads, Victoria
Acknowledgements
1.26
The committee thanks all of the individuals and organisations who submitted to the inquiry and appeared as witnesses.
Notes on references
1.27
References to Committee Hansard in this report are to the proof transcripts. Page numbers may vary between the proof and official transcripts.