Breast cancer cluster, ABC Toowong Queensland
First progress report of the independent Review and Scientific Investigation Panel: Outline of proposed approach to its task
Background
Female staff members employed by the ABC at its premises in Toowong,
Queensland, have reported what appears to be an unexpectedly large number of cases of breast cancer covering a period from the beginning of 1995 to the present.
Particular concern has been expressed at the occurrence of a number of cases in the TV newsroom, and at the relative youth of those affected. Action to address this issue began in February 2005 and has included:
• Engagement of a senior occupational health physician from Health Services Australia (Health for Industry) to advise on the issue;
• Involvement of the ABC’s Employee Assistance Provider – Davidson Trahaire Corpsych;
• Conduct of a radiofrequency electromagnetic radiation (EMR) survey of the ABC Toowong site by EMR technologies; and
• Investigation of the occurrence of breast cancer in women on the Toowong site by Queensland Health.
Staff concern about the breast cancer cases at the Toowong site was increased in July 2006 with the report of another staff member diagnosed with breast cancer.
The Independent Review and Scientific Investigation Panel
In response to the situation, the ABC’s Managing Director, Mark Scott, invited cancer and environmental epidemiologist, Professor Bruce Armstrong, Director of Research at the Sydney Cancer Centre, to constitute and lead an independent Investigative Panel with the following terms of reference:
1. Review the scientific work undertaken to date on the reported breast cancer cluster at Toowong including efforts made in 2005 to identify any cause;
2. Consider submissions and briefings from the staff-elected Staff Reference Group (SRG) and communicate with the SRG on the Panel’s work and plans;
3. Advise the ABC on further investigations that should be made to identify any cause for breast cancer clustering at Toowong;
4. Oversee the conduct of any such further investigations; and
5. Advise the ABC on any actions that should be taken in the light of the Panel’s review of existing information and the results of any further investigations done.
Dr Norman Swan, Producer and Presenter of the ABC’s Health Report, Professor Malcolm Sim, Director of the Monash Centre for Occupational and Environmental Health, and Associate Professor Joanne Aitken, Director of the Viertel Centre for Research in Cancer Control at the Queensland Cancer Fund, are the other expert members of the Panel. At Professor Armstrong’s request, the ABC has engaged Ms Lesley Walker, an environmental epidemiologist, to assist the Panel.
The Panel is independent in the sense that it:
• Will seek to apply sound scientific principles to its review and
investigations and to apply only those principles when formulating its advice;
• Is freely able to speak with both management and staff about its investigations and their outcomes and to seek information from and through both; and
• Will provide its progress and draft final reports to management and staff (through the SRG) at the same time; and
• Will take account of issues that both management and staff raise from the draft final report in preparing its final report.
The panel met for the first time on the 7th August in Brisbane. The following sections of this document were prepared following this meeting and summarise the Panel’s initial views on how it will approach its task.
Summary of work undertaken to date
The Panel had access to and viewed the following reports on investigations relevant to the cluster of breast cancer cases that had been undertaken to date:
1. RF Hazard Control Document Toowong Studio Brisbane Australian Broadcasting Commission – Date of Survey 16th February 2004 – THL Australia
This report identified the following radio frequency (RF) electromagnetic radiation sources on the site:
and identified the following RF hazards with reference to the ARPANSA (2002) reference levels applicable to the site:
2. Questionnaire – Breast cancer cluster study, Australian Broadcasting Corporation Toowong – Dr Keith Adam, Health for Industry
Dr Adam was engaged to: complete an exposure history [for cases of breast cancer]; confirm cases through accurate clinical diagnosis; educate staff about the occurrence of disease; review the results of the testing by EMC Technology; and provide the ABC with an evaluation report. The Review Panel understands that:
• Dr Adam gave a lecture to the staff;
• Dr Adam developed and circulated questionnaire to employees reported to have had breast cancer;
• Some questionnaire recipients were concerned that the questionnaire did not adequately address possible hazards in the workplace;
• Few questionnaires were completed and staff members withdrew their cooperation with Dr Adam’s investigation; and
• Dr Adam did not prepare an evaluation report.
3. Electromagnetic radiation survey conducted for Australian Broadcasting Corporation at 600 Coronation Drive, Toowong, Qld Australia. Report number B050401, issue date 2nd May 2005. EMC Technologies Pty Ltd.
EMC Technologies did a survey of broadband RF electromagnetic radiation (electric fields 100 kHz to 45 GHz and magnetic fields 100 kHz to 30 MHz) on the ABC Toowong site on 4th to 6th April 2005. Results of this testing were reported to the staff on 6th May 2005. All the tests were reported as complying with reference levels of ARPANSA. Measurable levels were reported in proximity to security card readers and areas inside outside-broadcasting vans.
4. Queensland Health investigation into concerns about a breast cancer cluster in women working at the ABC studios, Toowong. Queensland Health, December 2005
In May 2005 Queensland Health was requested by concerned ABC staff members to investigate whether there were more breast cancer cases in the female
workforce than would be expected and to consider whether the working
environment might be responsible for the development of breast cancer in affected
women. The results of the investigation were reported in December 2005. The report concluded that:
• The occurrence of eight cases of proven breast cancer in a small workplace over this time period raises the likelihood that this is a statistical excess of cases;
• Applying standard epidemiological techniques, where the workplace per se rather than a specific environmental factor is considered the risk, proved to be difficult as it was not possible to fully identify and accurately quantify the exposed population. A definitive, valid statistical conclusion about the expected number of cases in the workplace over the period could not be drawn from the data;
• Therefore, in this instance, where the epidemiological investigation was unable to definitively answer the initial question related to excess of cases an environmental appraisal of the workplace was undertaken;
• The subsequent environmental appraisal did not indicate any plausible exposures that would explain a significantly elevated number of breast cancers.
In response to a request for clarification, Queensland Health provided the following additional conclusions in February 2006:
• There remains a likelihood that there is an excess of breast cancer cases in this workplace, however the size of any potential excess cannot be exactly quantified;
• An excess would most likely be due to coincidence, but an excess may be due to factors, which in the present state of scientific knowledge, are unknown or unrelated to the workplace. Given the current state of scientific knowledge and that the investigation focussed on the workplace, workplace-related factors are considered an unlikely explanation.
Panel members reached the following conclusions from their review and discussion of these documents:
1. It has not yet been established whether the observed number of cases of breast cancer in female employees of the ABC at its Toowong premises is greater than might reasonably be expected in a female workforce of its size and age
distribution;
2. RF levels measured in different locations in the ABC Toowong premises, including in proximity to where some of the affected women worked in the TV newsroom, were reported to be generally below the detection threshold for the instrument used. This conclusion, however, seems to be based on spot
measurements at each location. Longer-term monitoring of RF levels is likely to give a more accurate estimate of usual exposure, as they will take into account the intermittent operation of some equipment.
3. As reported, the investigations done so far appear not to have considered the full range of other possible exposures on this site.
We therefore recommend that further investigations are done.
Epidemiology of breast cancer on the Toowong site
Following its review of the documents and discussion with the Staff Reference Group (SRG), the Panel concluded that an epidemiological study should be conducted, covering the period 1st January 1995 to the present. This would encompass the relevant period during which the cases of breast cancer were diagnosed.
From information available to it, the Panel believes that it is possible to prepare a reasonably accurate estimate of the number of person years of employment of female staff members on the Toowong site of the ABC that can be used to estimate expected numbers of breast cancers.
The Queensland Health report stated that there were 8 cases of breast cancer in ABC employees at Toowong in the periods 1995 to 2005. Another case has been reported since, making 9. Members of the SRG suggested that the number could be as high as 11 or 12. The SRG expressed its willingness to collate workforce knowledge of cases of breast cancer diagnosed in ABC employees at Toowong during the period specified above. Given the publicity surrounding the issue of breast cancer in ABC employees at Toowong and the salience of the issue to them, we consider that the staff’s
collective knowledge of cases of breast cancer in their work colleagues should provide complete or near complete enumeration of these cases.
We recommend that:
1. The ABC collates information on its whole female workforce in the period from 1st January 1995 to the present that would allow accurate estimation of the person years of employment for female staff members during this period. We will advise on how this should be done.
2. The assistance of the whole staff is sought, through the SRG, in identifying all cases of breast cancer diagnosed in this period in women while they were employed by the ABC on the Toowong site. It is important to ensure that all possible breast cancer cases are identified. Whatever process is followed in doing this should ensure that women who are identified are asked if they consent to their names and contact details being given to the Panel before any such disclosure is made.
3. The Panel seeks a standard set of information from women who have had or may have had breast cancer. For the purposes of the epidemiological study this would include: date of birth, date of diagnosis of breast cancer, circumstances leading to diagnosis (eg, mammographic screening in the absence of specific symptoms, or after feeling a lump or onset of some other breast symptom) and pathological details of the breast cancer. To obtain this latter information, it may be necessary to ask women to provide the Panel with consent to obtain medical information from their treating doctor.
4. The processes in (2) and (3) are approved by an appropriately constituted human research ethics committee before any identifiable personal information is
disclosed to the Panel.
5. The Panel uses the information obtained in (1) and (3) to estimate the ratio of the observed number of breast cancers to its expected number (based on the person
years of employment and Queensland Cancer Registry estimates of breast cancer incidence in Queensland for the period 1995 to the present) and the 95%
confidence interval for the ratio. These calculations would be based on rates of invasive breast cancer. Sensitivity analyses would be done based, for example, on different ways of counting person years for casual employees, different
assumptions about the characteristics of breast cancer in women who had breast cancer but for whom the full information in (3) could not be obtained, and inclusion of women with in situ breast cancer if plausible estimates of its
incidence in the whole population could be made, at least for a period, from data held by the Queensland Cancer Registry.
6. The Panel reports the results of the analyses in (5) in a progress report to management and staff as soon as they have been completed and reported to the Panel’s satisfaction.
Additional investigations
While it might be argued that no additional investigations should be done until the study of the Epidemiology of breast cancer on the Toowong site has been completed, we consider that it is in both management’s and staff’s interest that some additional investigations proceed in parallel with that into the epidemiology. This will reduce the likelihood of major delay in the Panel’s final report.
Workplace and other exposure history of women who have had breast cancer In approaching women for the brief details required for the epidemiological study, we recommend that additional, more detailed information be sought, as listed below. This information will allow a full assessment of the extent of spatial and temporal
clustering of the cases of breast cancer, possible exposures within the ABC Toowong site, and other occupational or non-occupational characteristics that women who have had breast cancer may share. Specifically, we recommend that:
1. Women who have been diagnosed with breast cancer, including carcinoma in situ, while employed at the ABC Toowong between 1995 and the present are asked in detail about their work, work patterns (including shift work) and workplace location histories during their employment with the ABC (at Toowong and
elsewhere). An interviewer with occupational health experience and qualifications would undertake these interviews.
2. These women are also asked about their family history of breast cancer and exposure, through lifestyle or other means, to other known risk factors for breast cancer.
Longer term monitoring of RF radiation
While the levels of RF have been reported to be lower than ARPANSA reference values in workplaces on the ABC Toowong site, only spot measurements have been made. While there is limited evidence that increased exposure to RF increases risk of human cancer, given the role that RF plays in the ABC’s operations, the possibility of important levels of exposure to it in the ABC Toowong site should be thoroughly considered.
We recommend that there be continuous monitoring of RF over longer periods in areas where there are high concentrations of staff and, in particular, in the TV
newsroom and in proximity to where the TV news production staff members sit, and at times when all relevant equipment is operational. The exact areas to be monitored will also be guided by the occupational histories given by the women with breast cancer. The measured levels should be compared with benchmark measurements from a range of other workplaces in the telecommunications industry and not just assessed against accepted reference levels for workplaces.
Measurement of extremely low frequency electromagnetic radiation (ELF) ELF is produced by the passage of power frequency alternating electrical current in power lines. While high levels of ELF are commonly associated with high voltage power transmission lines, there are circumstances in which high levels can also occur as a result of the way electrical power is distributed in buildings. High exposure to ELF has been associated with childhood leukaemia, although the current state of scientific knowledge does not suggest an association with breast cancer. Nevertheless, there is concern among ABC staff about levels of ELF exposure at the Toowong site.
We recommend that a survey be made of ELF levels in workplaces on the ABC Toowong site. Continuous monitoring over periods of time should be done in areas where there are high concentrations of staff and, in particular, in the TV newsroom and in proximity to where the TV news production staff members sit. If measurable levels are found, they should be compared with benchmark measurements from a range of other workplaces and not just assessed against accepted reference levels for workplaces.
Documentation of history of the Toowong site relevant to possible sources of carcinogenic exposure
While the scientific evidence for ionising radiation being a cause of breast cancer is very strong, there is less evidence for other specific occupational or environmental risk factors for breast cancer. However, due to staff concern about exposure to other possible carcinogens at the Toowong site, such as organochlorine pesticides, PCBs, heavy metals such as cadmium or lead, and organic solvents, it will be important to assess the possible presence of such hazards and, if present, the degree of likely exposure.
We recommend that:
1. A detailed review is undertaken of the literature relating to occupational and environmental exposures as risk factors for breast cancer; and
2. A detailed history of the Toowong site is compiled with a particular focus on:
• instances of possible environmental contamination with chemicals – eg, chemical waste, pesticides (eg termite control), solvents, PCBs, heavy metals, formaldehyde (as from building material or furnishings), flooding; and
• changes in location of RF transmission aerials or other relevant equipment or power transformers and cabling that could have produced a major change in exposure to RF or ELF.
3. Should our review of the epidemiology of breast cancer at the Toowong site suggest that there is an increase in risk of breast cancer on the site that is beyond what might be reasonably attributed to chance variation, it might be necessary to make more extensive environmental measurements on the site. These
measurements would be guided by results of the review of literature relating to environmental and occupational exposure to breast cancer and would focus initially on exposures that the site history suggests are plausibly present on the site.
