WA Asbestos Review Program Dr Fraser Brims Consultant Respiratory Physician, SCGH, Head of Occupational and Respiratory Health Unit, LIWA Asbestos awareness week seminar, 2014
Introduction Asbestos and the lung Legacy of asbestos in WA WA mesothelioma registry Asbestos Review Program Results of 2 years of low dose CT screening
Asbestos and the lung Benign effects Pleural plaques Rolled atelectasis Diffuse pleural thickening Benign asbestos related pleural effusion Asbestosis Malignant Malignant mesothelioma Lung cancer
Asbestos Exposure at Wittenoom Machine miner Machine bagger (new mill) Hand bagger (new mill) Hand bagger (old mill) New mill average Old mill average f/cc 20 80 100 130 50 80
Western Australia Mesothelioma Register 1971-
Mesothelioma is not going away Olsen, MJA 2011
Asbestos Review Program (ARP) 1990 surviving members of Wittenoom workers cohort invited to take part in cancer prevention program Regular annual surveillance 2007 analysis demonstrated no benefit
Asbestos Review Program (ARP) Non-Wittenoom cohort also developed 3 months full time equivalent of occupational exposure to asbestos Presence of pleural plaques Mixed fibre, low-medium exposure Majority of the cohort
Trades Carpenters, joiners, builder Plumber Boilermakers Fitters, turners, machinists Telecommunications Mechanic, fitter, panel beaters Marine engineers Shipwrights Waterside workers
ARP End 2013 n=4241 (3462 men) participated Smoking, alcohol, dietary questionnaires Blood (biomarkers, DNA) Lung function (FEV 1, FVC, DLCO) Annual CXR* 1,333 deaths all causes 197 lung cancer 189 mesothelioma
2012: Introduction of low dose CT - Rationale Until 2012: annual CXRs (i.e. pre-screened) CT and CXR Asbestos causes lung cancer too Carefully controlled LDCT screening programs for lung cancer improve mortality by 20%
Relative Risk of lung cancer Asbestos exposed, never smoker: 1.08-2.82 No asbestos, smoker: 1.78-10.13 Asbestos exposed, smoker 5.57-25.20 Multiplicative risk Straif, 2009; deklerk, 1991; Reid 2006; Lee, 2001
Australian Statistics 5-year survival 1982-1987 2006-2010 Lung 8.7% 14% Breast 72% 89% Colorectal 48% 66% Prostate 57% 85% Most lung cancer cases ~80% inoperable at diagnosis Cancer Australia
Why low dose CT? Background (Perth) 2-3 msv CXR PA& Lat 0.1 msv Standard CT Chest 5-8 msv PET-CT >10-15 msv LDCT <5 msv Ultra LDCT <1 msv 0.1 to 0.15mSv at PMH and Envision 7 Hour flight 0.02 msv
Methods All subjects offered LDCT as part of annual review Prone, no IV contrast Indeterminate nodule volume of at least 50mm 3 semi-solid nodules >5mm Scans read by specialist thoracic radiologist Weekly MDT
Characteristics of the cohort Age (mean, SD) 68.8 (9.9) Male 83.4% Smoking status: Current 6.5% Ex 57.2% Never 36.4% Pack years (mean, SD) 17.1 (25) Asbestos exposure Wittenoom worker 16.0% Wittenoom resident 24.3% Other occupational 59.7% Mean time since1 st exposure (years, SD) 50.8 (9.0) Mean exposure duration (months, SD) 149 (175)
Results Year 1 Year 2 Total subjects 906 973 1 st scan 906 (100%) 115 (11.8%) Indeterminate nodule 79 (8.85%) 42 (4.3%) Recall 77 (8.4%) 37 (3.8%) Lung cancer 7 (0.77%) 3 (0.3%) Mesothelioma 4 (0.44%) 0* All lung cancer cases asymptomatic All year 2 lung cancers are incident cases
Lung cancer cases N=10 No symptoms 9 stage 1a (1 stage IIa) Treatment 8 VATS lobectomy 1 stereotactic radiotherapy 1 declining Rx
Lung cancer cases Smoking Current 1 Ex 7 Never 2 Asbestos exposure Wittenoom worker 4 Wittenoom resident 3 Other 3
Performance In year 1, 402 participants chose to still have a CXR Using this group as a comparator: Sensitivity 100% Specificity 92% PPV 8.86% False positive rate 91.1%
Nodules 58% nodules on the right Site N= LUL 16 Lingula 4 LLL 24 RUL 15 RML 15 RLL 30
Incidentals Non-lung cancer Renal carcinoma 2 Gastric cancer 2 Thymoma 1 Colon cancer 1 Mediastinal lymphadenopathy 10 Aortic aneurysm 3
Pleural plaques 577 (63.5%) have pleural plaque 512 (56.4%) calcified Visceral 18.3% Diaphragm 77.6% Visceral and parietal 17.1% Majority LML / lingula& RML
Is LDCT reliable for asbestosis? 365/906 noted to have evidence of fibrosis 143 subjects have concurrent gas transfer values Manuscript in preparation
Results Malignant mesothelioma: 4 subjects
Conclusions Prevalence lung cancer 0.77% MPM 0.45% Incidence: 0.3% LDCT is effective at detecting early LC Only in a carefully controlled specialist program Lung cancers Asymptomatic, early stage 9/10 had potentially curative therapy
Asbestos Review Program Metamorphosed from a research to clinical program Future directions AsbJEM Continue to re-examine dose-response relationships Expanding numbers wider population Participants derive a great deal of comfort from their annual review
Asbestos Review Program (ARP) Still recruiting: 3 months regular asbestos exposure +/- pleural plaques Refer potential participants to: ARP@health.wa.gov.au FraserBrims@health.wa.gov.au
Why not combine the exposure for commercial benefit? Kent asbestos filter cigarettes
Questions. fraser.brims@uwa.edu.au fraserbrims@health.wa.gov.au
20% reduction in lung cancer mortality with LDCT screening 53,454 Participants 55 to 74 years; 30 pack-years Median follow-up 6.5 years NEJM 2011; 365:395-409
TSANZ position statement - in preparation The use of CT for uncontrolled ad hoc screening for asymptomatic lung disease is strongly discouraged
This is an emerging and very specialist field IASLC working group: Needs specialist MDT Part of a carefully defined project Cost effectiveness needs further evaluation Size vs. volumetric analysis. Smoking cessation Nodule management Field et al, JTO 2012