Document ypJ916DnRwLbwQwEbaMMbY8jd

FILE NAME Brakes BRK DATE 1978 Aug DOC BRK073 DOCUMENT DESCRIPTION Journal Article - Mesothelioma in Relation to Asbestos Fibre Exposure - SA Medical Journal 12 August 1978 SA MEDICAL JOURNAL 279 Mesothelioma Relation to Asbestos Fibre Exposure A Review of 70 Serial Cases J. C. COCHRANE I. WEBSTER 2 SUMMARY mesothelioma cannot be accepted as an occupational Seventy consecutive patients suffering from mesothelioma of the pleura were referred to the National Research Institute for Occupational Diseases In only 1 case was it not possible to elicit a history of significant exposure to asbestos dust An occupational and environmental history must be taken by a knowledgeable person before it is possible to conclude that there has been no asbestos exposure disease since in so many cases the cause is unknown and presumably not related to asbestos exposure The need to obtain a clear picture of the association between asbestos exposure and mesothelioma has been stressed by Selikoff et al who recommend that research leading to clarification and resolution of the foregoing statistical uncertainty be treated as a matter of considerable concern To under- line this concern two recent articles have reported groups ~ S. Afr med J. 54 279 1978 Lynch and Smith in 1935 were probably the first to record the association between respiratory neoplasms and exposure to asbestos fibre They reported an increased of cases extreme contrast in one series there was showing 98 exposure in another there was no asbestos and exposure in 36 cases By reporting this predominantly positive series we do not suggest that all cases of mesothelioma everywhere in the world are caused by exposure to asbestos fibre It is incidence of carcinoma of the lung in workers suffering presented to prove that a history of exposure to asbestos from asbestosis a relationship which has subsequently received considerable attention However the neoplasm of concern in relation to asbestosexposure is clearly mesothelioma of the pleura can be established in a significant number of cases if histories are taken from the patient and recorded by medical specialists with experience in the field of occupational medicine By this report it is also hoped to in- peritoneum Primary mesothelioma of the pleura or is rare andis foundin 0,02-0,20,2-0,2 0,02-0,2 of all autopsy cases in the Western world This neoplasm has been a named specific hazard of heavily exposed asbestos workers an observa- fluence the recognition of mesothelioma as an occupational disease in South Africa and iin n other countries where it is not yet so defined -~: tion which demands careful study Yet much that has HISTORY OF MESOTHELIOMA IN -~ been written on the clinical and historical_background historical_background of cases of mesothelioma is not exhaustive The reason is - SOUTH AFRICA that many articles have been written by pathologists who are involved in the difficult diagnostic aspects of the tumour but who are not responsible for taking patient histories Too many specimens certainly in South Africa and probably elsewhere reach pathologists with the short clinical note No asbestos exposure Also many series have been based on postmortem results with occupational histories provided in retrospect by family members or fellow workers Such histories not taken from the patients themselves would be unacceptable in other spheres of clinical medicine In 1957 Wagner et al studied 33 histologically proven o cases of mesothelioma at what was at that time the Pneumoconiosis Research Unit in Johannesburg Past occupation and place of residence were investigated in detail In all but 1 case they were able to establish a satisfactory history of exposure to asbestos thus a very significant percentage of association By 1962 Wagner pleural had diagnosed a total of 87 and 2 peritoneal meso- theliomas of which 12 occurred in patients with industrial exposure to asbestos and the remainder in patients from the regions of the Cape asbestos fields In only2 cases was On the other hand it must be accepted that there are it not possible to establish a history of exposure to asbestos series with a high percentage of mesothelioma cases in which no history of exposure to asbestos can be established Johannesburg Asbestos Symposium 1977 The percentage of mesothelioma patients with histories negative for asbestos fibre exposure has been high in certain series -- up to 30 Consequently and unfortunately legal opinion in many countries has held that dust _ In 1973 Webster reviewed 232 cases of pleural meso- thelioma diagnosed as such by the South African Asbestos Tumour Reference Panel comprising leading South . African histopathologists In % the occupational history was not known and 14 were reported as having no history of asbestos exposure Most of the cases in this series had been investigated with the aid of relatives and % National Research Institute for Occupational Diseases of the South African Medical Research Council Johannesburg J. C. COCHRANE B.SC M.D. M.R.C.P. I. WEBSTER B.SC. HONS M.B. B.CH. F.R.C. PATH fellow workers after postmortem diagnosis PATIENTS AND METHODS The 70 patients reported in this series Table ) have all Date received 8 May 1978 been referred to the National Research Institute for Occu- sa eee pet oe HT coe Mane AEE RRM gecmne ee Ine ee Vet cle RO ee ER kee REE ERSeee HOF CORE ERE ee NOL WELRNE ee TA be ae! 2 IOI TENM BA Pr BT Be SED THER wast tg re oF > Iw SIS SF 280 SA MEDIESE TYDSKRIF 12 Augustus 1978 pational Diseases by thoracic surgeons of Johannesburg and the Johannesburg General Hospital In 69 of the patients there was substantive evidence of asbestos contact in 1 patient only could no satisfactory history of asbestos fibre contact be obtained Johannesburg draws a considerable percentage of unusual cases in South Africa but obviously not all The Asbestos Tumour Reference Panel reviewing material from all the provinces has over the same period 4 years dealt with a further 154 cases making a total of 224. The total number of cases of mesothelioma at present entered in the register is 711 up to October 1977 These have been collected over a period of 25 yearsyears Johannesburg Also when the tumour is suspected many Black workers faced with a diagnostic exploration refuse further investigation and return home Few miners are included in the present series because it is based on those patients referred to the Institute from the mining industry The few patients recorded under Mining Table ) had spent only part of their careers in that industry as miners or in supportive activities e.g. as electricians This 5; ay Fr - period had however been the significant although incidentally uncovered time of their asbestos exposure ae . History Histories were taken from patients by one or other of TABLE 1. SOURCE OF CONTACT IN MESOTHELIOMA the authors usually by both Where confirmation of ex- . _&F PATIENTS EXPOSED TO ASBESTOS -- posure to asbestos fibre was necessary it was obtained > occupational environmental - lived on asbestos mines Northern Cape ... owe wee wee ... Environmental and occupational Cape - roarod ad worker surfacing with asbestos tailings 00 ... 0 ... ue Asbestos transport workers drivers and loaders ... ... Medical officer on asbestos mine ... ... ... .. Asbestos mining . Underground miners se. oss vs : ee ... Mill surface workers ... instalo 0. 0. we ee ee) Boilermakers lagging surface installations Asbestos industry = Mixing raw materials 00.000. cee ee Laboratory workers and others in constant contact with quantities of asbestos including maintenance fitters Sheet cutting ... ... ... tee see tee ... ee Transport and loading of asbestos outside mining areas Locomotive workshops Asbestos insulation of boilers ... ... Ship engine room repairs ... ... 0... 0 6.0 eee ... ... ee) Welders in other workshops using asbestos cloth in- - sulation gloves and rods ... ... ... ++ ... - Building . from executive or government sources All interviews were a repeated at least once This was necessary to give the ~ 13 patient an opportunity to think over the details and en- vironmental aspects of his working career With from 1 exposure intervals varying from 9 to 40 years = 5 in this series stress had to be laid on the worker's early + 1 history and for many recall was not immediate ; 4 -- The requirement of an adequate and a significant ex- 72 posure as applied to this group was a minimum of -2 2 months of constant exposure to an atmosphere of visible -~4: 2 floating asbestos fibres or 4 years in room contact with loose asbestos fibre not visible in the atmosphere 4 For environmental cases a minimum of 3 years resi dence was required in a mining area on mine property 5 where floating fibre was more or less constantly in the air or in a town where for example the subject had 3 played in the grounds of an asbestos mill on dumps : opyen <ggesay 2332 Rees of asbestos tailings during childhood ob- 12 The following are examples of positive histories ob- 2 tained on requestioning or rethinking : 1. An electrician employed on the gold mines who was - 2 examined and recorded as gold mines only -- no asbestos . contact recalled that he had for 2+ years cut drilled and _ Asbestos blocks sheet cutting for ceilings and roofs and proofing with asbestos materials ... ... Electrical Electricians exposed 1 year or more to high concentra- tions of fibre in closed areas underground or in ceilings or workshops- ... ... 0.0 -. ee ... - Boilers - workshops . Installation demolition or repair -- Asbestos textile handling ~ Jewellery manufacture .. 0... 0... cee cee ee tee : . Total ee. eee ... ee ee ee nee nee nee ee vee | 3 "~ 8 2 1 69 fitted asbestos panels to electric switches in small under- ground stations Throughout the period plumbers were working next to him in these confined areas stripping old asbestos lagging from all piping and replacing it with new . second electrician 2. A on a gold mine who was recorded as no contact recalled that he had been withdrawn from his normal work for 2 years to make experimental fish- friers for hostels out of asbestos sheeting and with asbestos fibre insulation and lagging This was done in a small workshop without a protective mask During his apprenticeship he occasionally spent time throwing snowballs of - one : --7=8 =~ asbestos at his fellow workers > All patients reported here have been subjected to open thoracotomy biopsy The biopsy specimens were examined by the staff of the National Research Institute for Occupational Diseases and referred to the South African Asbestos Tumour Reference Panel who confirmed the diagnosis malignant mesothelioma Of the cases reported 61 are White and 9 Black The paucity of Blacks can be explained as such patients are referred to their regional hospitals and not to the thoracic surgeons in 3. A third electrician who was positive that he had never worked with or near asbestos later recalled that he had worked for 9 months in the roof spaces of a hospital installing electric wiring while plumbers were ~ putting in pipes with extensive asbestos lagging and insulation and builders were fitting asbestos ceilings He finished each day white with dust He had also for 2 years done repairs in ship engine rooms while asbestos lagging was being replaced