Estimation of the Burden of Cancer in Great Britain due to ... · 1 Dept. of Epidemiology and...

Estimation of the Burden of Cancer in Great Britain due to Occupation

L Rushton1, T. Brown2, R Bevan3, J Cherrie4, L Fortunato1, S Bagga3, P Holmes3, S Hutchings1, R Slack3, M Van Tongeren4, C Young2

1 Dept. of Epidemiology and Public Health, Imperial College London; 2 Health and Safety Laboratory, Buxton, Derbyshire3 Institute of Environment and Health, Cranfield University4 Institute of Occupational Medicine

This study was funded by the Health and Safety Executive

Aims of the study

• Aims of the study:– to develop and apply methodology to estimate current

attributable risk, cancer numbers and DALYs caused by work– to identify important cancer sites– to identify industries and occupations for targeting for reduction

measures– To estimate the future occupational cancer burden in GB under

different scenarios of changing exposure

• Selection of carcinogens and occupations for estimation: – classified by IARC as group 1 (established) and 2A (probable)

carcinogens– with strong or suggestive evidence of carcinogenicity in humans– 24 cancer sites; 42 carcinogenic agents or occupations; over

100 industry sectors

Measure of Burden• Measure of burden used is the AF - proportion of cases

attributable to exposure; needs– risk of disease associated with the exposure of concern (e.g.

relative risk (RR))– proportion exposed in the population

• RR from published literature: meta-analyses, pooled studies, narrative reviews where available

• Selected studies with comparable exposures to GB:– Large sample size– Clear case definition– Appropriate comparison population– Controlled for confounders where possible– Adequate exposure assessment

• Risk estimates obtained for overall ‘higher’ level of exposure and lower/background exposure

Estimating the Proportion Exposed• To take into account latency (length of time before

disease risk increases) we defined the risk exposure period (REP) for:– Solid tumours: 10-50 years; 1956-95– Leukaemia: up to 20 years; 1986-2005

• Proportion exposed over the REP is:number ever exposed/number ever worked

• Estimated using national data sources (CAREX, LFS, CoE)

• Adjusted for turnover, change in numbers employed over REP

Trends in employment structure in Great Britain, based on Labour Force

Survey data from 1975 to 2007 and projected to 2025, men

0

4,000

8,000

12,000

16,000

20,000

1975

1980

1985

1990

1995

2000

2005

2010

2015

2020

2025

Year

Empl

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)

Agriculture, Hunting and Forestry, FishingMining, Manufacturing, Electricity, gas and water supplyConstructionService sectorTotal

Attributable Numbers and DALYs

• Apply AFs to total nos. of site-specific cancer deaths and registrations to give attributable nos. of deaths and registrations for each carcinogen (ANs)

• AFs and ANs give no idea of the relative ‘costs’ to an individual or society of an occupationally caused cancer

• Apply AFs to measures of:a. Years of life lost (YLL)b. Years lived with a disability (YLD)

• Combine to give DALY• DALYs are a measure of something lost – future years

of life and future years lived without severe mental or physical disability

Cancer Site AF (%) Deaths (2005) Registrations (2004)

M F Total M F Total M F Total

Mesothelioma 97.0 82.5 95.0 1699 238 1937 1699 238 1937

Sinonasal 46.0 20.1 34.4 29 10 39 101 32 133

Lung 21.1 5.3 14.5 4024 726 4749 4632 816 5477

Nasopharynx 11.0 2.5 8.2 7 1 8 14 2 16

Bladder 7.1 1.9 5.3 215 30 245 496 54 550

Breast 4.6 4.6 555 555 1969 1969NMSC 7.1 1.1 4.6 21 2 23 2576 352 2928

Larynx 2.9 1.6 2.6 17 3 20 50 6 56

Oesophagus 3.3 1.1 2.5 156 28 184 159 29 188

STS 3.4 1.1 2.4 11 3 13 22 4 27Stomach 3.0 0.3 2.0 102 6 108 149 9 158

NHL 2.1 1.1 1.7 43 14 57 102 39 140Melanoma (eye)

2.9 0.4 1.6 1 0 1 6 1 6

Total 8.2 2.3 5.3 (4.6, 6.6)

6362 1657 8019 (6891, 9983)

10063 3616 13679 (9310, 20235)

Carcinogen or Occupation Total Registrations Cancer Sites

Asbestos 4216 Larynx, Lung, Mesothelioma, Stomach

Shift work (+ Flight Personnel) 1957 Breast

Mineral oils 1730 Bladder, Lung, NMSC, Sinonasal

Solar radiation 1541 NMSC

Silica 907 Lung

Diesel engine exhaust 801 Bladder, Lung

PAHs - Coal tars and pitches 545 NMSC

Painters 359 Bladder, Lung, Stomach

Dioxins 316 Lung, NHL, STS

Environmental Tobacco Smoke (non-smokers) 284 Lung

Radon 209 Lung

Welders 175 Lung, Melanoma (eye)

Tetrachloroethylene 164 Cervix, NHL, Oesophagus

Arsenic 129 Lung

Strong inorganic-acid mists 122 Larynx, Lung

Chromium 89 Lung, Sinonasal

Non-arsenical insecticides 73 Brain, Leukaemia, Multiple myeloma, NHL

Steel foundry workers

Tin miners Mineral oils Welders

Radon

Haematitemining

Hairdressers & Barbers

Ionisingradiation

ETS

Nickel

ChromiumArsenicArt glass

Cadmium

Dioxin

Nonarsenical insecticides

Acid mists

Painters

Silica

Diesel

PAHs *

BCCM CMME

Isopropyl alc.

Epichlorohydrin

αCT & BC

Construction

Stainless steel

Smelting/RefiningAlloys/Plating

Batteries Pesticide Sprayers

Drivers

Asbestos

Personal &Household Services

Metal machinists

ConstructionQuarriesPottery

Beryllium

MetalsMetals

Talc containing asbestiform fibres

Paper

Paints

Coal‐tar and pitchesAlluminium production

Coal gasificationCoke production

Soot

Foundries/ Steel mills

Cobalt

Lead

Mining

Rubber Industry

Shipbuilding

Dyes/pigments

Arsenic

Asbestos

Beryllium

Cadmium

Chromium IV

Cobalt

Diesel engine exhaust

ETS

Inorganic lead

Ionising radiation

Mineral oils

Nickel

PAHs

Painters

Radon

Silica

Steel foundry workers

Strong inorganic‐acid mistsContaining sulphuric acid

TCCD

Tin miners

Welders

Lung cancer AF by carcinogen/occupation

Industry Sector Attributable RegistrationsMale Female

Exposures

Construction 4752 64 14

Painter + decorators 331 3 1

Roadmen + roofers 538 3 1

Total construction 5621 71 16

Shift work (including flight personnel) 0 1970 1

Metal workers 1081 169 1

Personal + household services 274 530 17

Land Transport 436 43 9

Mining 285 17 10

Printing, publishing and allied trades 225 34 10

Public administration and defence 239 34 6

Wholesale + retail trades 110 159 11

Farming 180 39 5

Welders 165 16 2

Manufacture of instruments, etc 204 16 6

Manufacture of transport equipment 170 18 16

Non-ferrous metal basic industries 125 34 18

Cancer Registrations Attributable to Work in the Construction Industry ‐Men

0 500 1000 1500 2000 2500 3000 3500 4000

ArsenicAsbestosChromium

CobaltDieselETS

FormaldehydeLead

PaintersPAH

PAH ‐ coal tarsand pitches

RadonSilica

Solar RadiationTetrachloroethylene

Wood dust

Carcinogen

Number of Registrations

Construction, inc painters anddecorators; road surfacers,roadmen, roofers & glazers, paviours

Other Sectors

500 1000 1500 2000 2500

Registrations

Bladder

Larynx

Lung

Mesothelioma

Nasopharynx

NMSC

Oesophagus

Sinonasal

Stomach

Attributable Registrations by Cancer Site forWork in the Construction Industry: Men

YLLs and YLDs for cancer due to occupation, men, excluding lung cancer + mesothelioma

0 500 1,000 1,500 2,000 2,500 3,000

BladderBoneBrain

BreastCervixKidneyLarynx

LeukaemiaLiverLH

Melanoma_eyeMultiple Myeloma

NasalNasopharynx

NHLOesophagus

OvaryPancreas

NMSCSTS

StomachThyroid

Years

YLLs

YLDs ‐uncured

YLDs ‐cured

YLLs and YLDs for cancer due to occupation, women, excluding breast and lung cancer and mesothelioma

0 50 100 150 200 250 300 350 400 450

BladderBoneBrainCervixKidneyLarynx

Leukaemia (all) Liver

LymphohaematopoieticMelanoma_eye

Multiple MyelomaNasal

NasopharynxNHL

OesophagusOvary

PancreasNMSC

Soft Tissue SarcomaStomachThyroid

Years

YLLsYLDs –non‐survivors

YLDs ‐survivors

Cancer Site YLL (years)

Deaths (2005) Average YLL (years)

DALY (years)

Bladder 2543 245 10.4 3110Brain 222 11 20.2 232Breast 9600 555 17.3 13797Cervix 156 7 22.3 195Larynx 290 20 14.5 414Leukaemia 407 24 17.0 442Lung 62913 4749 13.2 66080Mesothelioma 26942 1937 13.9 27738

Nasopharynx 158 8 19.8 183

NHL 964 57 16.9 1029

NMSC 208 23 9.0 277

Oesophagus 2528 184 13.7 2691

Ovary 383 23 16.7 418

Sinonasal 652 39 16.7 2691

STS 296 13 22.8 336

Stomach 1331 108 12.3 1460

Total 109810 8019 13.7 119491

Predicting Future Burden

• AFs estimated for forecast years, e.g. 2010, 2020 … 2060

• Define the risk exposure period (REP) for each year e.g. for 2030, 1971 – 2020

• Assume latencies are distributed lognormally across the REPs

• Some past and some future exposure.

• Workers at the beginning assumed to be of all working ages

• Workers recruited through employment turnover are assumed to be only aged 15-24

• Methods being applied to ‘important’ carcinogens/occupations identified from current burden results

20602020

1971‐80 2001‐101981‐90 1991‐00

Risk Exposure Periods Forecast Target Years20502030 2040

2021‐302011‐20 2031‐40 2041‐50

2010

1961‐70

10 year estimation intervals

‘Known’ exposure Forecast exposure

Forecast Risk Exposure Periods – 10‐50 year latency

Possible change scenarios• No change in exposure levels or patterns (baseline)• Linear employment and exposure level trends assumed to 2021‐

30, constant thereafter• Test time of introduction of a reduced or new limit (silica,

tetrachloroethylene, TCDD, arsenic)• Test ‘dynamic exposure standard’ that reduces as forecast levels

are expected to fall and previous intervention standards take effect

• Test compliance by workplace size• Test effect of introducing lower exposure standards versus

compliance rate • Test effect of closing industries, reducing exposed numbers

(asbestos, radon), transferring high/medium exposed workers to low exposed (solar radiation), and lowering RR (painters, welders)

Example Intervention Scenarios for Silica

• Reduce exposure limit from 0.1 to 0.05 mg/m3 in all workplaces, in 2010, with the same proportion exposed above the new limit as above the old

• Reduce exposure limit again to 0.025 mg/m3

• Improve compliance from 33% to 90% in all workplaces

• Try doing both for all workplaces• Successively enforce the new limit and improve

compliance in workplaces of different sizes

Forecast lung cancer registrations, age 25+, based on population projections and 2004/5 cancer rates by age

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Year

Can

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GB total registrations - men

GB total registrations - women

GB projected population age 25+ - menGB projected population age 25+ - women

Testing reduction of exposure standard and changes in complianceForecast lung cancers for 2060 for Respirable Crystalline Silica

2010Attributable

FractionAttributable registrations

Avoided registrations

3.3 803

2060

Base-line: exposure limit 0.1mg/m3, compliance 33%

1.08 794

Exposure limit 0.05mg/m3, compliance 33% 0.80 592 202





0100200300400500600700800900

1,000

2010 2020 2030 2040 2050 2060 2070 2080

Att

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Forecast year

Forecast Attributable Numbers for Lung cancer and exposure to RCS, Men + Women


Exposure limit 0.05mg/m3, compliance 33%





Testing improvement in compliance by workplace sizeForecast lung cancers for 2060 for Respirable Crystalline Silica

2010Attributable Fraction %

Attributable registrations

Avoided registrations

3.3 803

2060


1.08 794


Exposure limit 0.05mg/m3, % compliance changes by employed workplace size and self employed33% < 250, self employed; 90% 250+ 0.68 499 295

33% < 50, self employed; 90% 50+ 0.61 451 344

33% self employed; 90% all sizes employed 0.35 261 533

90% all workplaces 0.07 49 745

0100200300400500600700800900

1,000

2010 2020 2030 2040 2050 2060 2070 2080

Att

ribu

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gist

ratio

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Forecast year

Forecast Attributable Numbers for Lung cancer and exposure to RCS, Men + Women



Exposure limit 0.05mg/m3, compliance 33% < 250, self employed; 90% 250+

Exposure limit 0.05mg/m3, compliance 33% < 50, self employed; 90% 50+

Exposure limit 0.05mg/m3, compliance 33% self employed; 90% all sizes employed

Exposure limit 0.05mg/m3, compliance 90% all workplaces

Shift work• Breast cancer due to shift

work likely to increase due to expected increase in service sector employment

• Intervention scenarios: limit proportions exposed for durations of 15+ and 5+ years

• Benefits increase with increased restrictions on years spent on shift work.

• Cancers eliminated by 2060 if exposure for 5+ years eliminated by 2010 (excess risk zero for <5 years exposure)

• Cancers reduced by 94% by 2060 if 90% rather than the current 30% are restricted to <5 years on night shifts.

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500

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2,500

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2010 2020 2030 2040 2050 2060

Attri

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Forecast year

Shift work: breast cancer, women

(1) Current employment levels maintained, 30% <5, 40% 5-14, 30% 15+ years night shift work

(2) Linear employment trends to 2021-30(3) 50%<5, 30% 5-14, 20% 15+ years night shift work(4) 70%<5, 20% 5-14, 10% 15+(5) 90%<5, 10% 5-14, 0% 15+(6) 100% <5 years

Strong Inorganic Acid Mists

• IARC Group 1 for lung and laryngeal cancers• Risk estimates higher for laryngeal cancers:

H L BLarynx 4.28(2.13, 8.88) 1.91(0.97, 3.78) 1Lung 1.36(0.97,1.94) 1.00• Current burden estimates (total burden)

AF% Deaths RegistrationsLarynx 2.13 (2.61) 16 (20) 46 (2112)Lung 0.20 (14.5) 67 (4748) 76 (4877)• Currently 96% compliance to current WEL 0.3mg/m3

Reduction of exposure standard for Strong Inorganic Acid Mists

2010

Larynx cancer Lung cancerAF% Attributable

registrationsAvoided

registrationsAF% Attributable

registrationsAvoided

registrations

1.9 44 0.19 78

2060

Base-line: 2005 exposure levels maintained 0.1 5 0.003 2

8% linear decline in exposure until 2021-30, constant after 0.5 17 0.029 21

Exposure limit 0.06mg/m3, compliance 90% 0.3 12 6 0.010 7 14




0102030405060708090

100

2010 2020 2030 2040 2050 2060Attr

ibut

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regi

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Forecast year

Strong inorganic acid mists : larynx cancer

0102030405060708090

100

2010 2020 2030 2040 2050 2060Attr

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regi

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Forecast year

Strong inorganic acid mists: lung cancer

Monitoring success

• Monitor exposure levels

• No reduction in cancer levels until 2030 at earliest (solid tumours)

• After 2030– Use achieved exposed numbers/proportions exposed

at new exposure levels in same (target setting) forecast model to get achieved AF

– Apply achieved AF to same (2005 based) cancer projections to get achieved attributable numbers

Uncertainties and the impact on the burden estimation

Source of Uncertainty Potential impact on burden estimateExclusion of IARC group 2B and unknown carcinogens e.g. for electrical workers and leukaemia

↓

Inappropriate choice of source study for risk estimate

↑↓

Imprecision in source risk estimate ↑↓

Source risk estimate from study of highly exposed workers applied to lower exposed target population

↑

Risk estimate biased down by healthy worker effect, exposure misclassification in both study and reference population

↓

Inaccurate latency/risk exposure period, e.g. most recent 20 years used for leukaemia, up to 50 years solid tumours

↓

Effect of unmeasured confounders ↑↓

Unknown proportion exposed at different levels ↑↓

Summary• Robust methodological approach developed for estimation of burden

for all IARC 1, 2A occupational carcinogens

• Adapted for WHO Global Burden update; Used to inform socio-economic impact analysis of effect of introducing limits for certain carcinogens for DG Employment; HSE costs of workplace illness will include cancer for the first time.

• On-going work: Evaluation of impact of source of bias and uncertainty

• Outputs: – Preliminary work on 6 cancer sites: OEM 2008, 65, 789-800; – Results from all sites: BJC 2010, 102: 1428-1437– Supplement in preparation on current burden detailed results in BJC,

2011 + approx. 24 technical reports + database– Methodology paper on future burden methodology AJE in press– Future burden results in preparation

Estimation of the Burden of Cancer in Great Britain due to ... · 1 Dept. of Epidemiology and...

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