Cancer clusters kNOw Cancer - 2015 Constructively dealing with concerns about cancer clusters Tim...
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- Cancer clusters kNOw Cancer - 2015 Constructively dealing with
concerns about cancer clusters Tim Driscoll University of
Sydney
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- Cancer clusters kNOw Cancer - 2015 Aims Provide an overview of
cancer clusters Consider the main issues Recommend an approach
Propose some principles Case study
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- Cancer clusters kNOw Cancer - 2015 What is a cancer cluster?
Various definitions An unusually high number or rate of cancer -
(given the relevant population and time period) Usually describes
one type of cancer, but may include different types of cancer
Should NOT imply a connection with a single cause, but often this
is what is meant by people using the term
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- Cancer clusters kNOw Cancer - 2015
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- A few concepts about cancer Common disease Usually more common
with age Long latency Usually has one or more known risk factors
Has a random component differences in rates often due to
chance
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- Cancer clusters kNOw Cancer - 2015 Why is it so hard?? Most
cancers can be caused by more than one type of exposure The same
exposure can occur in different settings Long latency obscures the
connection to exposure Usually no way to determine the cause in an
individual case Random doesnt mean even
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- Cancer clusters kNOw Cancer - 2015 What is chance?
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- Cancer clusters kNOw Cancer - 2015 What is chance? Random
co-location of different risk factors over time and place Random
occurrence of cases over time and place
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- Cancer clusters kNOw Cancer - 2015
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- When do concerns arise?
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- Cancer clusters kNOw Cancer - 2015 When do concerns arise?
Cases of the same cancer type Lots of cases Young people Concerning
exposures Not giving initial concerns appropriate consideration
Industrial relations or community issues
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- Cancer clusters kNOw Cancer - 2015 Should clusters be
investigated? To summarise, I would recommend that we spend less
time reacting to reports of disease clustering, less time trying to
detect general patterns of disease clustering, and less time
developing new methods to conduct these activities. Ken Rothman,
1990 It is fair to state that extensive efforts to find causes of
community cancer clusters have not been successful. There are
fundamental shortcomings to our current methods of investigating
community cancer clusters. Goodman et al, 2012 Critical Reviews in
Toxicology2012;42(6):474490 AJE 1990;132(Suppl 1):S6-S13
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- Cancer clusters kNOw Cancer - 2015 Why bother?
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- Cancer clusters kNOw Cancer - 2015
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- Cancer types involved Breast Bladder Colon Kidney Myeloma
Multiple 511117511117
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- Cancer clusters kNOw Cancer - 2015 Settings involved Office
setting University Industry Public service Research institute
Residential care Art Gallery Fire station School
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- Cancer clusters kNOw Cancer - 2015 When do concerns arise?
Cases of the same cancer type Lots of cases Young people Concerning
exposures Not giving initial concerns appropriate consideration
Industrial relations or community issues
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- Cancer clusters kNOw Cancer - 2015 When should concerns be
raised?
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- Cancer clusters kNOw Cancer - 2015 When should concerns be
raised? Number of cases? Type of cancer? Ages of affected persons?
Type of exposures? Never?
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- Cancer clusters kNOw Cancer - 2015 When should concerns be
raised? Number of cases?...........Usually need more than just a
few Type of cancer? Ages of affected persons? Type of
exposures?
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- Cancer clusters kNOw Cancer - 2015 When should concerns be
raised? Number of cases?...........Usually need more than just a
few Type of cancer?...............Rare or unusual cancers; same
type Ages of affected persons? Type of exposures?
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- Cancer clusters kNOw Cancer - 2015 When should concerns be
raised? Number of cases?...........Usually need more than just a
few Type of cancer?...............Rare or unusual cancers; same
type Ages of affected persons?.....Young people Type of
exposures?
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- Cancer clusters kNOw Cancer - 2015 When should concerns be
raised? Number of cases?...........Usually need more than just a
few Type of cancer?...............Rare or unusual cancers; same
type Ages of affected persons?.....Young people Type of
exposures?..........Known carcinogens; known connection to
identified cancers
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- Cancer clusters kNOw Cancer - 2015 Challenges
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- Cancer clusters kNOw Cancer - 2015 Challenges Lack of
information about exposure Uncertainty about case definition
Incomplete case identification Uncertainty about population at
risk
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- Cancer clusters kNOw Cancer - 2015 Challenges Interpretation of
statistical tests Public perception that there must be a problem
Context Other agendas Ethics restrictions / requirements
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- Cancer clusters kNOw Cancer - 2015 Response
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- Cancer clusters kNOw Cancer - 2015 Response Prompt response
Explain the challenges Emphasis on exposures and case
characteristics rather than on rates Involve all interested parties
(reference group) Regular feedback
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- Cancer clusters kNOw Cancer - 2015 The extent of investigation
can vary The extent of investigation depends on the specific
circumstances Sometimes a discussion and a brief site visit is all
that is needed Sometimes a detailed investigation is clearly
indicated Always start by talking at an early stage to the
concerned people
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- Cancer clusters kNOw Cancer - 2015 Two stage approach Stage 1:
review of past and current exposures - ALL carcinogens, with a
focus on the relevant ones Stage 2: epidemiological analysis of
cancer cases - emphasis on case characteristics Stage 1 and Stage 2
usually overlap Good communication throughout
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- Cancer clusters kNOw Cancer - 2015 Driscolls four principles
for investigating cancer clusters
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- Cancer clusters kNOw Cancer - 2015 Important principle 1 Cancer
cluster investigations are socio-scientific phenomena - Good
science is not enough - Good science AND good communication and
consultation is required
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- Cancer clusters kNOw Cancer - 2015 Important principle 2 If no
concerning exposures are found but there is a high
rate....................... .. it is almost certain that the high
rate was due to chance If still concerned, need to study another
workplace/community with a similar exposure
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- Cancer clusters kNOw Cancer - 2015 Important principle 3 If
rate is not high but concerning exposures are
found................................... .Fix the exposures!
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- Cancer clusters kNOw Cancer - 2015 Important principle 4 When
concerns about a cancer cluster arise, the cancers nearly always
turn out not to be (or almost certainly not to be) related to work
(or community) exposures BUT....it is important to still
investigate properly
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- Cancer clusters kNOw Cancer - 2015 The key aspects
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- Cancer clusters kNOw Cancer - 2015 The key aspects Focus on the
exposures and the concerns of the individuals Listen to ALL
concerns and address them to the extent possible Communicate early
and often Instead, we should focus more on exposure assessment and,
where indicated, cleanup. Ken Rothman 1990 A duty of care was seen
to be met when the investigation was extended beyond carcinogens
that would account for the cluster to all carcinogens that were
worrying those affected. Bernard Stewart 2007 AJE 1990;132(Suppl
1):S6-S13 MJA 2007; 187: 178180
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- Cancer clusters kNOw Cancer - 2015 Advantages and
disadvantages
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- Cancer clusters kNOw Cancer - 2015 Advantages of investigation
Provide reassurance that carcinogenic exposures in the setting are
CURRENTLY not present or are well controlled OR Identify exposures
that are not well controlled so they can be FIXED
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- Cancer clusters kNOw Cancer - 2015 Advantages of investigation
2 Provide insight into whether PREVIOUS carcinogenic exposures in
the setting were likely or not likely to be responsible for
identified cancers Provide guidance regarding whether the
identified occurrence of cancer is or isnt unusual Provide a forum
for concerns to be addressed There is little choice - the concerns
rarely disappear!
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- Cancer clusters kNOw Cancer - 2015 Disadvantages of
investigation In many cases the rate of cancer will not be shown to
be higher (i.e. there is no cluster) A causal connection to an
exposure is very rarely identified Commonly costly in terms of time
and resources The final outcome is commonly not definitive
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- Cancer clusters kNOw Cancer - 2015 Investigation of a reported
cluster of cancer cases at the National Gallery of Australia Final
report Tim Driscoll Gary Foster Felicity Driscoll September
2008
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- Cancer clusters kNOw Cancer - 2015 National Gallery -
background Concerned staff Management perceived as slow to react
Initial investigation very limited Staff more concerned and
unhappy!
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- Cancer clusters kNOw Cancer - 2015 National Gallery what did
the study team do? Set up a reference group Reviewed relevant
scientific literature Workplace investigation for carcinogens
Interviewed workers (but not all cases) Number, rate, type and
characteristics of cancer in current and past workers
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- Cancer clusters kNOw Cancer - 2015 National Gallery - exposures
IARC Group 1 Asbestos Benzene Cadmium Environmental tobacco smoke
Ethylene oxide Formaldehyde Radium Wood dust X-rays
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- Cancer clusters kNOw Cancer - 2015 National Gallery - exposures
IARC Group 1 Asbestos Benzene Cadmium Environmental tobacco smoke
Ethylene oxide Formaldehyde Radium Wood dust X-rays IARC Group 2A
Diesel fumes Epichlorohydrin Polycyclic aromatic hydrocarbons
Tetrachloroethylene
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- Cancer clusters kNOw Cancer - 2015 National Gallery - exposures
IARC Group 1 Asbestos Benzene Cadmium Environmental tobacco smoke
Ethylene oxide Formaldehyde Radium Wood dust X-rays IARC Group 2A
Diesel fumes Epichlorohydrin Polycyclic aromatic hydrocarbons
Tetrachloroethylene IARC Group 2B Carbon black Carbon tetrachloride
Cobalt Dichloromethane Dichlorvos Extremely low-frequency electro-
magnetic fields Magenta Potassium bromate Synthetic mineral fibres
Welding fumes
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- Cancer clusters kNOw Cancer - 2015 National Gallery - exposures
IARC Group 1 Asbestos Benzene Cadmium Environmental tobacco smoke
Ethylene oxide Formaldehyde Radium Wood dust X-rays IARC Group 2A
Diesel fumes Epichlorohydrin Polycyclic aromatic hydrocarbons
Tetrachloroethylene IARC Group 2B Carbon black Carbon tetrachloride
Cobalt Dichloromethane Dichlorvos Extremely low-frequency electro-
magnetic fields Magenta Potassium bromate Synthetic mineral fibres
Welding fumes
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- Cancer clusters kNOw Cancer - 2015 National Gallery what was
found? 57 current and former workers diagnosed with cancer Types
with the highest numbers were the most common community cancer
types Little to suggest common exposures of cases (except security
guards) All cancers..........................................No
increase Lung cancer........................................40%
increase (very likely due to chance) Bowel
cancer.......................................6% increase (very
likely due to chance) Bowel cancer (security
guards)..........Increased risk (very likely due to individual risk
factors)
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- Cancer clusters kNOw Cancer - 2015 National Gallery what was
found? Lots of carcinogens No exposures at a level that would
meaningfully increase risk
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- Cancer clusters kNOw Cancer - 2015 National Gallery what was
concluded? Very unlikely that any of the cancers identified in
Gallery staff members were related to exposures experienced while
working in the Gallery building No further investigation of the
issue considered necessary Re-design the loading dock
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- Cancer clusters kNOw Cancer - 2015 National Gallery what was
the outcome? The loading dock was demolished as part of renovations
The new loading dock is very well designed No further issues re
cancer The gallery's deputy director, Alan Froud, said he was
pleased the report put to rest the long-running concerns. The
former head of conservation and a long-term critic of the gallery's
health and safety practices, Bruce Ford, said he was pleased it had
been cleared. But the cancer study had not addressed his broader
concerns about the health of the building. SMH 3/10/2008
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- Cancer clusters kNOw Cancer - 2015 Jilalan rail yard:
assessment of exposures and concerns regarding cancer amongst
current and former workers Final report Tim Driscoll ELMATOM Pty
Ltd April 2010
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- Cancer clusters kNOw Cancer - 2015
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- Guidance in Australia NHMRC:
https://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/ps0006_statement_cancer_clusters.pdf
https://www.nhmrc.gov.au/_files_nhmrc/publications/attachments/ps0006_statement_cancer_clusters.pdf
Cancer Council:
http://www.cancer.org.au/news/blog/risks/what-are-cancer-clusters.html
http://www.cancer.org.au/news/blog/risks/what-are-cancer-clusters.html
Queensland Health:
http://www.health.qld.gov.au/epidemiology/documents/faq-cancer-cluster.pdf
http://www.health.qld.gov.au/epidemiology/documents/faq-cancer-cluster.pdf
Vic Health:
http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Disease_clusters
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- Cancer clusters kNOw Cancer - 2015 Change what you can
change
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- Cancer clusters kNOw Cancer - 2015 Change what you can change
Stop smoking Exercise regularly Eat plenty of vegetables and fruit
Maintain appropriate weight Avoid excessive alcohol consumption
Restrict sun exposure
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- Cancer clusters kNOw Cancer - 2015 Conclusions
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- Cancer clusters kNOw Cancer - 2015 Conclusions 1 Cancer is a
common disease Cancer clusters: are expected due to random
variation are usually not caused by occupational or environmental
exposures are very rarely due to unknown exposures should not be
dismissed without investigation of some sort good communication is
essential
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- Cancer clusters kNOw Cancer - 2015 Conclusions 2 Prompt
response Explain the challenges Emphasis on exposures and case
characteristics rather than on rates Involve all interested parties
Regular feedback Change what you can change
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- Cancer clusters kNOw Cancer - 2015