Document N2DN4zD3GpG4YX3oY1nqqn7z8

fpEQ.b3.200t 07:16P'FR0M: TO:16182590896 :5'13 216 INDUSTRIAL CARCINOOHNESIS AND TOWCOLOOY experimental work on mouso and rabbit skin, some such idea must be evoked by a problem such as that of asbestosis and cancer, until some more experi mental evidence of direct carcinogenesis by asbestos or a decomposition product) or u can be obtained. Tf such an idea is feasible, then we must also assume p pre-neoplastic preparedness in the organ in which the co-carcmogcn (usbestos or the fibrous tissue in the peribronchiolar reaction) later induces u further development into true neoplastic growth. The preparedness of the tissue if it is to be regarded as more than a form of words is brought about by something independent of the asbestosis, and this must be regarded us an endogenous factor. But some special property must also attach to the asbesto! is foi the alleged cancer Induction in this condition is not apparently found in the long-stunding cases of silicosis- We will firpt consider the evidence that asbestosis leads in a proportion of cases tc camper of the lung. As long ago as 1938 the suspicion arose that asbestos workers might be more than normally prone to lung cancer. Nordjnarm (1938) analysed six cases of lung cancer and showed that the range of exposure periods was 7 21 years, and the rango of intervals between entering the industry and death was 13 to 21 years The malignant disease in some cases occurred years after leaving the industry. Half of these cases were co nparauveiy young, 33-41 years of uge at death. In one remarkable case a 11-year old woman had worked in asbestos for only 19 months. Later in the'same year he referred to a further seven cases of associated asbestoi is and lung cancer, including Gloyne's (1936) finding of six cases of carcinoi aa of the lung in SO necropsy cases of asbestosis. Tn tic 1947 Annual Roport of the Chief Inspector of Factories, Merewether [tabulated the age incidence among 235 deaths caused by asbestosis: in 13*2 per cent or these cancer of the lung was present, and it is especially imporlunl to note that 4*8 per cent of the age-group 25-34 years and 5*6 per cent of the age-group 35-44 years had this condition, ll will be seen that the over-all figure is closely in agreement with Gloync's findings. In a further report* carrying this analysis up to the end of 1934, be found tipat amongst 344 deaths, in 55, or 16*0 per cent, cancer of the lung was present. In their senes of papers on asbestosis Lynch and Cannon (1948) give an analysis of the post-mortem examination of 40 cases of asbestosis among which 3 case,s of carcinumu of the lung were found associated with medium or advanced grades of asbestosis, which, according to these authors, is seven times tha general incidence in the United States. In a r tore recent study of the clinical picture and pathology of asbestosis, Behrens (1952) estimated that of 309 cases of asbestosis reported in the literature there were 44 cases of carcinoma of the lung (14-2 per cent) whereas in a senes of 2,204 cases of silicosis only 32 such tumours were found ( *4 per cent). * Annual Report Chief Inspector o! Factories Tor 1954, pp, 190-195 Jw discrepancy \ raer. as that found Suggestive as thei with th< Hies of 235 cases e chds again .almi j|Jher,series of SaSjbing.the c JvcHpg.pipeswitl wearing a respiratc bbngh nothing not '`i.bone marrow. L shadows whi ___r ^tumours. aftered large not ffical3 examinatio *stic .carcinoma some doubt Jpfmuthors incline SPflie problem of i suggest that gect of its com] V^less eomprorr fe~'lly that in ' about 1J-20 yet jtblished in the ^successfully c yeajjsofworkina: ^gdiographic invei *'frer lung field . ilddle ahd lower Lobectomy of ratiniang squai yasToccupied by i nour. Asocsto ^ugh node. Rec gpansion of the 1 ^suggestive ca ^.ycars.who 15 jlustry. Necroi jcinoma accom uthdr is cautious T#4