Asbestos and the lungs- myths and truths. Dr Malcolm Ogborne MBBS FRACP

Transcription

1 Asbestos and the lungs- myths and truths Dr Malcolm Ogborne MBBS FRACP

2 Summary O Asbestos fibers- general O Asbestos-related pleural disease (ARPD) Pleural plaques Pleural effusions Round atelectasis O Asbestosis O Bronchogenic carcinoma (lung cancer) O Mesothelioma

3 Asbestos fibers- general O Mined by the ancient Greeks O Used extensively in manufacture world-wide up until late 20th century O Fire resistant, electrically insulating, tensile strength, sound absorbtion, versatile, cheap. O Plaster, vinyl floors, roofing, acoustic ceilings, fireproofing and heat insulation, electrical insulation, brake pads, gaskits, chemical filters, stage curtains, shoes etc etc

4 Asbestos fibers- general O Serpentine fibers (curly) Chrysotile: 90% of world-wide manufacture, most versatile O Amphibole (needle-like) Amosite (brown): South Africa Crocidolite (blue): Wittenoom, southern Africa, Bolivia Tremolite: India, Turkey, Greece

5 Chrysotile Asbestos

6 Crocidolite Asbestos

7 Asbestos fibers- general O Pliny the Younger AD noted ill health amongst asbestos workers O Asbestos-related dust diseases scientifically described since 1920s UK Parliamentary report 1930 led to regulation of industry to reduce exposure 1932, US 1942 O Dr J Wagner 1960 recognised the association between asbestos and mesothelioma Wagner Br J Int. Med, 1960, 17; O Mining ceased in Australia 1983, gradual phasing out of materials from Total ban since 2003

8 Asbestos fibers- general O Fibers deposited in respiratory bronchioles and alveolar interstitium O Mucociliary clearence the main defence Chang Am J Pathol 1988, 131:156 Smoking significantly impairs mucociliary defences O Attacked by MØ, type 1 pneumocytes Brody Am Rev Resp Dis 1981;123:672 O Inflammatory response, formation of asbestos bodies, attempted removal to pleura.

9 ARDP- Pleural Plaques O 50% of all exposed patients O Parietal pleural adjacent to the ribs, bilateral less in intercostal spaces absent at apicies, costophrenic angle Tip of dome of diaphragm pathognomic O Calcified in 50% on CT (80% at biopsy) O Usually benign process, monitoring not required may cause lung restriction with normal DLCO

10 ARPD- Pleural Plaques

11 ARPD- Pleural plaques

12 ARPD- Pleural plaques

13 ARPD- Benign Asbestos- related Pleural Effusions O Occur most commonly 1-15 years after the onset of exposure, but have been reported up to 50y Epler, JAMA 1982, 247:617 O Small, unilateral Patient usually asymptomatic O Serous, serosanguinous, bloody >1/3 have high EØ count (up to 50%) Mattson, Scand Resp Dis 1975, 56:263 O Resolve over several weeks May leave pleural thickening/ blunting of angle O Main DD is mesothelioma- associated effusion

14 ARPD- Round Atelectasis O Can occur with any pleural inflammation, particularly prevalent in ARPD Mintzer, Chest 1982; 81:457 O Progressive tethering of adjacent lung in a pincer-like process gradually forms a ball of scarred lung O Main DD is a metastatic malignant deposit but: Often unilateral Associated pleural plaque disease PET scan or biopsy only occasionally needed

15 ARDP- Round atelectasis

16 ARPD- Round atelectasis

17 ARPD- Round atelectasis

18 Asbestosis O Pulmonary fibrosis caused by asbestos exposure Appropriate history of exposure and/or radiographic evidence (pleural plaques) Latency years Mossman, N Engl J Med 1989; 320: 1721 Evidence of interstitial fibrosis: HRCT/ biopsy Absence of other potential causes O Insidious onset, slowly progressive Main symptom shortness of breath, cough late No chest pain, wheeze, sputum

19 Asbestosis O Usual Interstitial Pneumonia (UIP) pattern both radiologically and at biopsy O HRCT (30% may have normal CXR) Gamau AJR Am J Roenten 1995; 164: 65 Predominantly basal and dorsal fibrosis Subpleural microcystic change (honeycombing) Subpleural linear densities Coarse parenchymal bands 2-5cm, often contiguous with the pleura Aberle Clin Chest Med 1991; 12:115 O Gallium scan, BAL for asbestos bodies of limited use

20 Asbestosis

21 Asbestosis

22 Asbestosis

23 Asbestosis O Treatment mainly supportive Smoking cessation Prevent further exposure Influenza and pneumococcal vaccinations Prompt treatment of infection Oxygen?newer anti-fibrotics- watch this space

24 Bronchogenic (Lung) Cancer O All fiber types now accepted as an independent risk for lung cancer Exposure without smoking 6x RR Smoking without exposure 11x RR Exposure and smoking >20 pack years 59x RR Hammond Ann NY Acad Sci 1979; 330: 473 O?screening CT if smoker and pleural plaques/ clear exposure O Other: laryngeal, renal, oesophagus, biliary Selikoff Environ Health Perspect 1990; 88: 269

25 Mesothelioma O Pleural carcinoma for which asbestos exposure is the only clearly established risk?ionising radiation Tward, Cancer 2006; 07:108 Teta, Cancer 2007; 109: 1432 O Estimated lifetime risk for an asbestos worker approximately 10% Selikoff Cancer 1980; 48: 2736 Risk is proportional to magnitude of exposure Type of fiber (crocidolite> chrysotile) Genetic: BAP-1 (histone transcription factor), other Carbone J Trans Med 2012; 10: 179?viral: SV40- not clear Cistaudo Cancer Res 2006; 66: 3049 De Rienzo J Cell Biochem 2002, 84: 455

26 Mesothelioma O Commonest presentation is an unexplained unilateral pleural effusion latency 30-40y, not <15 years Chest pain, dyspnoea, cough, systemic symptoms 60% right sided Only 20% have asbestosis, most will have pleural plaques Pass et al, Cancer: Principles and Practice 9 th Ed. LWW, 2011 p2052 O CT scan, PET scan O Biospy almost always required

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28 Mesothelioma

29 Mesothelioma

30 Mesothelioma O Mesothlin (Mesomark) Sensitivity 19-68%; in stage I-II disease 32% if a 95% specificity cutoff used Holleroet J Clin Oncol 2012; 30: 1541 In pleural fluid sensitivity 67%, specificity 98% Creaney, Thorax 2007; Not recommended as a sole diagnostic tool Osteopontin, fibulin-3 not established O Treament Surgery: Extra-pleural pneumonectomy; pleurectomy Radiotherapy to biopsy sites Chemotherapy Supportive care

31 Summary O Asbestos fibers- general O Asbestos-related pleural disease (ARPD) Pleural plaques Pleural effusions Round atelectasis O Asbestosis O Bronchogenic carcinoma (lung cancer) O Mesothelioma

32 Thank you