Document DG4jprEqRdDaqwE6ykJYRBvgo

value and importance ? Once the question? arc identified it United States in insulation workers have shown that tfie" may be easier to ihoose the forum in which to answer them. relative risks of developing lung cancer are: non-exposed non-smokers 1; asbestos exposed non-smokers 5; non -exposej Tonv Smith smokers 11; asbestos exposed smokers 53.* Because exposure Deputy txior UMJ increases the risk by a factor of five in both smokers and non-smokers the council recommends that smoking should be ` Anommou' Docs Britain need an academy of medicine? Br Afid J 19?9,n loll. :Godber O An in'tuute of health? The Times Hcjlth Supplement 1962 Feb 1y '* < col 1 -4 . J British .Medical Association. 7he medujl ven r*f nu.lcjr t:-ar. Tht report rj tn: lirrcl. Afcdicj/ AjjcYij/n>n\' BtjrJ of 5acm and EJucjtiet: Chichester - John AX'ilr> and Sons. 1983. disregarded. Cancer of the lung in asbestos workers may be di\ ided into two broad types. Firstly, peripheral adenocarcinoma, which is unrelated to smoking and accepted as being due to asbestos exposure. The second is squamous, undifferentiated, and small-cell cancer arising in proximal airways, certainly related to smoking but only doubtfully related to asbestos. Perhaps wisely, the council makes no attempt to distinguish between these and recommends prescription irrespective of type. Most Asbestos related diseases without asbestosis authorities accept that the risk of lung cancer is increased only when there has been heavy exposure to dust. Reasonable estimates of exposure may be made for people working in circumscribed places such as asbestos factories, but this may Asbestosis and mesothelioma are prescribed diseases under the be impossible for, say, shipyard workers or engineer? with intermittent exposure in various jobs, particularly in the distant Industrial Injuries Scheme and entitle the patient or his dependants to compensation. The term asbestosis should be past. Faced by this difficulty the council has made an ingenious used only to denote fibrosis within the lungs. The three other non-malignant conditions associated with exposure to asbestos are pleural plaque, pleural effusion, and diffuse pleural thickening. The industrial Injuries Council now recommends that, when it reaches a certain extent, the last of these should also be prescribed.1 Pleural plaques develop in the parietal pleura, seldom cause disability, and are not to be prescribed. Pleural effusions may be transient but some are chronic and may recur.2 No pre scription is proposed for these, but, under the new proposals, if they cause sufficient bilateral thickening of the pleura an application to a pneumoconiosis medical panel would lead to certification. Diffuse pleural thickening associated with exposure to asbestos has become increasingly recognised.3 J Both pleural layers are affected and restrict the expansion of the lung. Histological examination shows only non-specific fibrosis, and, as with effusions, the diagnosis depends on excluding other causes such as tuberculosis and other infections, collagen diseases, trauma, chronic uraemia, and drug induced fibrosis.5 With such exclusions, the Industrial Injuries Council is satisfied that bilateral diffuse pleural thickening in asbestos workers is likely to be industrial and recommends that dis ablement benefit should be awarded when the thickening is bilateral, is over 5 mm thick, and extends over more than a quarter of the chest wall. The prescription of this condition will be welcomed, though proposal that the presence of other indicators of asbestos exposure should justify certification. It recommends prescrip tion when primary cancer of the lung is accompanied by one or more of the following features: asbestosis, bilateral diffuse pleural thickening, and bilateral pleural plaques. Asbestosis provides clear evidence of heavy exposure, but, though bilateral diffuse pleural thickening and bilateral pleural plaques are linked with exposure to asbestos, the relation is less definite and more capricious.7 Moreover, pleural disease and asbestosis are also poorly correlated, for the former may appear in lightly exposed people such as the wives of asbestos workers and residents in the vicinity of asbestos mines and factories. Given a minimum exposure to dust, the development of pleural calcification, which facilitates the diagnosis of plaques, is probably mainly determined by age, usually taking over 20 years from the first exposure.' * Only some 15u of plaques are detectable during life,'*' but this proportion might be higher if oblique x ray views were used in addition to the routine ones." Hence probably the people who arc certified during life will not be all those who have plaques but only the minority in whom they are demonstrable. The case for necropsies in people who have had industrial exposure to asbestos and die of lung cancer is clear. The council's aim has been to identify people with sufficient exposure to dust to justify certification if they develop lung cancer. Workable regulations are difficult to devise, but the proposals favour those with pleural x ray shadows which may some may be dissatisfied that the disease has to be so extensive to allow certification. Nevertheless, the committee suggests that this requirement should be reviewed in the light of experience. The report also considers cancer of the lung in asbestos workers. At present this condition is not prescribed, but when it occurs in association with asbestosis it is considered to be a be the result of light exposure in the distant past and dis criminate against those with much heavier exposure who, for unknown reasons, do not develop pleural lesions or have not had time to do so. The council has decided against specifying a duration and degree of exposure as a qualifying condition because it considers this to be arbitrary and lacking in scientific validity. Even so, the criteria of pleural lesions that it sequel and benefit is payable. Claims which have been rejected during life may be successful after death because necropsy may disclose previously undiagnosablc mild asbestosis. The council now recommends prescription of lung cancer in patients with asbestosis and in certain other circumstances. In doing so it had to consider how to take account of smoking habits and the proposes are probably a less than satisfactory index and, though the extension of prescription will be welcomed--even if it requires legislation--probably many will find that the details of the proposals which are now before the Secretary of State for Health are unsatisfactory. D Davies amount of exposure which would justify certification. The problem of the contribution of smoking to lung cancer in Consultant Chest Physician, City Hospital, asbestos workers has been disposed of neatly.^tgdig ip ^ic Qf^oiungham NG* 1PH SEP 1983 9 "A _- l