1: 12 February 1954: Iain Macleod, Minister of Health: Written Answer
The Standing Advisory Committee on Cancer and Radiotherapy have had this matter under consideration for three years. As a result of preliminary investigations, a panel under the chairmanship of the Government Actuary was set up in 1953 to inquire and report. I have now been advised by the Committee in the following terms:
Having considered the report of the panel under the chairmanship of the Government Actuary on the statistical evidence of an association between smoking and cancer of the lung, and having reviewed the other evidence available to them, the Committee are of opinion: –
(1) It must be regarded as established that there is a relationship between smoking and cancer of the lung.
(2) Though there is a strong presumption that the relationship is causal, there is evidence that the relationship is not a simple one, since:-
(a) the evidence in support of the presence in tobacco smoke of a carcinogenic agent causing cancer of the lung is not yet certain;
(b) the statistical evidence indicates that it is unlikely that the increase in the incidence of cancer of the lung is due entirely to increases in smoking;
(c) the difference in incidence between urban and rural areas and between different towns, suggests that other factors may be operating, e.g., atmospheric pollution, occupational risks.
(3) Although no immediate dramatic fall in death-rates could be expected if smoking ceased, since the development of lung cancer may be the result of factors operating over many years, and although no reliable quantitative estimates can be made of the effect of smoking on the incidence of cancer of the lung, it is desirable that young people should be warned of the risks apparently attendant on excessive smoking. It would appear that the risk increases with the amount smoked, particularly of cigarettes.
I accept the Committee’s view that the statistical evidence points to smoking as a factor in lung cancer, but I would draw attention to the fact that there is so far no firm evidence of the way in which smoking may cause lung cancer or of the extent to which it does so. Research into the causes of lung cancer has been pressed forward by the Government and by other agencies in view of the increase in the incidence of this disease and we must look to the results of its vigorous pursuit to determine future action.
I should also tell the House that before these recommendations were considered by Her Majesty’s Government the tobacco companies had offered to give £250,000 for research. They have, on my advice, agreed to offer this money to the Medical Research Council.
2: 12 February 1954: Ministry of Health: Press statement
The Parliamentary Answer given <by> the Minister of Health today (Friday) (of which a copy is attached) is based on advice given to him by his Standing Advisory Committee on Cancer and Radiotherapy who for three years have been giving close consideration to the problem of the possible relationship between tobacco smoking and cancer of the lung. In view of the public interest and concern over this question it is, in the Minister’s opinion, of very great importance that uninformed and alarmist conclusions should not be drawn from the Committee’s advice and that the qualifications mentioned by the Committee in their advice should be fully realised.
In the Autumn of 1950 an article by Dr. Doll and Professor Bradford Hill in the British Medical Journal suggested that, on evidence arising from a statistical enquiry, there was a relationship between smoking and cancer of the lung. The Committee at that time considered that further evidence was needed. Late in 1952 a further article by Dr. Doll and Professor Bradford Hill, which confirmed their earlier conclusions, reports from research workers in the U.S.A., and the submission of arguments seeking to demonstrate that the relationship was not proved, led to a panel under the Chairmanship of the Government Actuary being asked in 1953 to enquire and report to the Standing Advisory Committee. The conclusions reached by this panel were considered by the Standing Advisory Committee who advised the Minister as in the attached statement.
Although it can be taken as established that a relationship between smoking and lung cancer exists, it is important to realise that this relationship is not a simple matter, that a great deal of information and research is still required and it is not possible to draw final conclusions. The Minister considers that it would be helpful, in order that the matter can be looked at in proper perspective, to set down firstly what facts are known about the relationship, and secondly what must be regarded as speculative and unproved.
Facts Which Are Known
The Minister would like to draw attention to the following facts, which are now well established:-
(1) There has been an increase in deaths from lung cancer in this country which began about 1919 and has continued ever since. The increase is much greater in males than females. Between 1911 and 1919 the number of deaths from cancer of the lung was about 250 per year. The rise which began about 1919 can be illustrated from the figures of deaths for 1931 as compared with subsequent years. In 1931 the number of deaths attributed to lung cancer in England and Wales was 1,358 for males and 522 for females. Those figures represented 5% of all cancer deaths and 0.5% of deaths from all causes in males, and 2% of all cancer deaths and 0.2% of deaths from all causes in females. The latest figures available, for 1952, showed a further increase in that 11,981 males and 2,237 females died from the disease. These represent 26% of all cancer deaths and nearly 5% of deaths from all causes in males, and 5% of all cancer deaths and 1% of deaths from all causes in females. The figures also show that the highest mortality rate from lung cancer in males occurred in the 65-74 age group, whereas in females the highest rate occurred in the 75 and over age group.
(2) Comparable increases have been reported in all countries from which reliable statistics are available. Factors such as the increasing age of the population and better diagnosis account for some of the rise but not the whole of it.
(3) Tobacco smoking lays some part in this increase. To use the language of statisticians, there is an “association”.
(4) It is certain that tobacco smoking cannot be the only factor since the disease occurs in non-smokers. Not one but several factors or a combination of factors must be regarded as responsible.
(5) The disease is more prevalent in urban areas than rural and different parts of the country suffer more than others.
(6) No substance producing cancer of the lung has yet been specifically identified in tobacco smoke. Certain tars derived from tobacco smoke have produced skin cancers in mice but this is not considered as being conclusive evidence of the presence of a substance producing cancer of the lung.
So much is known.
Further Evidence Needed
The following matters must, however, remain speculative until further evidence comes to light:-
(i) There is no firm evidence of the way in which smoking may cause lung cancer or of the extent to which it does so. All that can be said at present is that there is a presupposition that it does, but the evidence does not permit us to say any more than that.
(ii) The difference in incidence between town and country and between different towns suggests that other factors should be taken into account such as atmospheric pollution or risks from particular occupations, but no evidence is available of the extent to which these factors operate.
(iii) Although the risk of contracting the disease appears to increase with the amount smoked, particularly of cigarettes, no reliable factual estimate can be made of the precise effect of smoking.
In view of this, it is not possible to come to a final and definite conclusion on this matter. A good deal of research and information is needed before anything more firm can be said. Many investigations are taking place both in this country and abroad which bear directly on the problem and also into the related problem of the effect of atmospheric pollution on health. The Ministry are in close touch with the Medical Research Council on this, and there will be no hesitation in launching further research if any particular line shows promise. Opportunity is taken of paying tribute to the valuable pioneer work of Dr. Doll and Professor Bradford Hill and other workers who have given us what little information we have.
3: 7 May 1956: Robin Turton, Minister of Health: Oral Answer
Since my predecessor made a statement in February, 1954, investigations into the possible connection of smoking and cancer of the lung have been proceeding in this and other countries. Two known cancer-producing agents have been identified in tobacco smoke, but whether they have a direct role in producing lung cancer, and if so what, has not been proved.
The extent of the problem should be neither minimised nor exaggerated. The number of deaths from cancer of the lung has risen from 2,286 in 1931 to 17,271 last year. To place the figures in perspective – in 1954, out of every thousand deaths of men aged between 45 and 74, 77 were from bronchitis, 112 were from strokes and apoplexies and 234 were from cancer, of which 85 were cancer of the lung. Deaths of women from cancer of the lung are still not very significant and represent a small fraction of the total.
The chairman of a committee of the Medical Research Council which has been investigating the subject considers that the fact that a causal agent has not yet been recognised should not be allowed to obscure the fact that there is, statistically, an incontrovertible association between cigarette smoking and the incidence of lung cancer. The statistical evidence from this and other countries to which he refers tends to show that mortality from cancer of the lung is twenty times greater amongst heavy smokers than amongst non-smokers.
The Government will take such steps as are necessary to ensure that the public are kept informed of all the relevant information as and when it becomes available.
In answer to supplementary questions, Mr Turton said:
In my view, in the present stage of our knowledge, a national publicity campaign would not be appropriate.
It would appear that pipe smokers face a heavier risk than non-smokers, but the risk is substantially less than that incurred by heavy cigarette smokers. . . . [T]here is some evidence that the risk of contracting cancer of the lung decreases when smoking is given up.
Whenever any more knowledge becomes available, I shall deem it my duty to put it before the House at once. . . . I did tell the House some time ago that two cancer-producing substances had been identified in tobacco smoke.
4: 27 June 1957: Statement by Minister of Health
In their Annual Report, and more particularly in their special report on tobacco smoking and cancer of the lung . . . the Medical Research Council have advised the Government that the most reasonable interpretation of the very great increase in deaths from lung cancer in males during the past twenty-five years is that a major part of it is caused by smoking tobacco, particularly heavy cigarette smoking. The Council point to the evidence derived from investigations in many countries in support of this conclusion, in particular to identification of several carcinogenic substances in tobacco smoke.
2. The Government feel that it is right to ensure that this latest authoritative opinion is brought effectively to public notice, so that everyone may know the risks involved in smoking. The Government consider that these facts should be made known to all those with responsibility for health education. The Minister of Education included in his recently published Handbook for Teachers on Health Education advice about the dangers of smoking and he is circulating copies of this statement to local education authorities and education authorities generally. Corresponding action will be taken by the Scottish Education Department in Scotland. The Government now propose to bring these views to the notice of local health authorities who are concerned under statute in the prevention of illness and who are responsible for health education as a means of prevention. Local health authorities will be asked to take appropriate steps to inform the general public and in this task they will have the assistance of the Central and Scottish Councils for Health Education.
3. Once the risks are known everyone who smokes will have to measure them and make up his or her own mind, and must be relied upon as a responsible person to act as seems best.
4. The Medical Research Council are at present supporting an extensive programme of work designed to discover the way in which tobacco smoke exerts its effect and the relative importance of other factors, such as atmospheric pollution, which may also play a part in the causation of lung cancer. The recent expansion of this programme has been greatly assisted by a substantial grant made in 1954 by a leading group of tobacco manufacturers; on the advice of my predecessor, the present Minister of Labour, this sum was given to the Medical Research Council with complete discretion as to the choice of research projects to be supported and to the publication of results.
5. The work at present in progress consists largely of chemical and biological studies of the many different constituents of tobacco smoke and atmospheric pollution. In addition, surveys of the role of atmospheric pollution and of specific industrial hazards in the causation of the disease are being undertaken. Work along these lines is being supported in many centres in different parts so the country and the Council have also established as part of their own organisation three new research groups in Exeter, London and Sheffield, where long-term studies of different aspects of the problem are being carried out. Every opportunity will be taken by the Medical Research Council to pursue any promising new lines of research which may become apparent.
5: 27 June 1957: Medical Research Council statement:
‘Tobacco Smoking and Cancer of the Lung’
The Increase in Lung Cancer
In their Annual Report for 1948-50 the Council drew attention to the very great increase that had taken place in the death rate from lung cancer over the previous twenty-five years. Since that time, the death rate has continued to rise, and in 1955 it reached a level more than double that recorded only ten years earlier (388 deaths per million of the population in 1955 compared with 188 in 1945). Among males the disease is now responsible for approximately 1 in 18 of all deaths. Although the death rate for females is still comparatively low, it also has shown a considerable increase in recent years and the disease is now responsible for 1 in 103 of all female deaths.
Three comments may be made on these figures. In the first place, the trend over the last few years indicates that the incidence has not yet reached its peak. Secondly, the figures are not to be explained as a mere reflection of the introduction and increasing use of improved methods of diagnosis but must be accepted as representing, in the main, a real rise in the incidence of the disease, to an extent which has occurred with no other form of cancer. Thirdly, only a small part of the rise can be attributed to the larger numbers of older persons now living in the population; in the last ten years the lung cancer death rates among both men and women have risen at all ages from early middle-life onwards.
Possible Causes of the Increase
The extent and rapidity of the increase in lung cancer point clearly to some potent environmental influence which has become prevalent in the past half-century and to which different countries, and presumably also men as compared with women, have been unequally exposed. The pattern of incidence of the disease rules out any possibility that the increase can be due, in a substantial degree, to special conditions, such as occupational hazards, affecting only limited groups. It is necessary to seek some factor or factors distributed generally throughout the population, and in considering the possibilities it must be borne in mind that a very long period, 20 years or more, may elapse between exposure to a carcinogenic agent and the production of a tumour. From the nature of the disease attention has focussed on two main environmental factors : (1) the smoking of tobacco, and (2) atmospheric pollution – whether from homes, factories, or the internal combustion engine.
Smoking as a Cause of Lung Cancer
(a) Epidemiological Surveys
The evidence that heavy and prolonged smoking of tobacco, particularly in the form of cigarettes, is associated with an increased risk of lung cancer is not based on the observation that the substantial increase in the national mortality followed an increase in the national consumption of cigarettes. It is derived from two types of special inquiry. In the first, patients with lung cancer have been interviewed and their previous histories in relation to smoking and other factors that might be relevant have been compared with those similarly obtained from patients without lung cancer. The results of nineteen such inquiries (in this country, the U.S.A., Finland, Germany, Holland, Norway and Switzerland) have been published. They agree in showing more smokers and fewer non-smokers among the patients with lung cancer, and a steadily rising mortality as the amount of smoking increases. In the second type of inquiry, information has been obtained about the smoking habits of each member of a defined group in the population and the causes of the deaths occurring subsequently in the group have been ascertained. There have been two such investigations, one in the U.S.A. covering 190,000 men aged 50-69, and the other in this country covering over 40,000 men and women whose names appeared on the Medical Register of 1951. In both, the results have been essentially the same. The investigation in this country, which has now been in progress for more than five years, has shown with regard to lung cancer in men
(1) a higher mortality in smokers than in non-smokers;
(2) a higher mortality in heavy smokers than in light smokers;
(3) a higher mortality in cigarette smokers than in pipe smokers;
(4) a higher mortality in those who continued to smoke than in those who gave it up.
It follows that the highest mortalities were found among men who were continuing to smoke cigarettes, heavy smokers in this group having a death rate nearly 40 times the rate among non-smokers. Although no precise calculation can be made of the proportion of life-long heavy cigarette smokers who will die of lung cancer, the evidence suggests that, at current death rates, it is likely to be of the order of 1 in 8, whereas the corresponding figure for non-smokers would be of the order of 1 in 300. The observation on the effect of giving up smoking is particularly important, since it indicates that men who cease to smoke, even in their early forties, may reduce their likelihood of developing the disease by at least one half.
It should be noted that the excess of deaths from lung cancer among smokers was not compensated for by any corresponding reduction in the number of deaths from cancer of other sites in the body; in other words, there was a total incidence of cancer in the smoking groups in excess of the incidence that would have prevailed in the absence of smoking.
It will be apparent from what has been said that the evidence from the many inquiries in the last eight years, both in this country and abroad, has been uniformly in one direction and is now very considerable. It has been further strengthened recently by the observation from several sources that the extent of the relationship with smoking differs for different types of lung tumour which can be distinguished only by microscopic examination.
From the physical and chemical point of view there is nothing inherently improbable in a connection between smoking and lung cancer. Tobacco smoke consists largely of microscopic oily droplets held in suspension in air, and these droplets are of a suitable size to be taken into the lungs and retained there. Over a hundred constituents have so far been identified and, among these, five substances have already been found which are known to be capable, in certain circumstances, of causing cancer in animals. Some workers have succeeded in producing tumours in animals by painting concentrated extracts of tobacco tar on the skin. Known carcinogens are present in tobacco smoke in very small amounts however, and there is no certainty that such low concentrations could be harmful to human beings. Nevertheless, the finding of carcinogenic agents in tobacco smoke is an important step forward, in that it provides a rational basis for the hypothesis of causation.
Atmospheric Pollution as a Cause of Lung Cancer
It has been known for some years that mortality from lung cancer is greater in urban areas than in the countryside. This fact, together with the identification of carcinogenic substances in coal smoke and in motor vehicle exhausts, has led to the supposition that exposure to atmospheric pollution may be concerned with the increase in lung cancer. The role of atmospheric pollution is particularly difficult to investigate however, and the evidence is neither so consistent nor so extensive as that relating to tobacco smoking. On the one hand, no excess mortality from lung cancer has been observed in persons who would be especially exposed by the nature of their work to atmospheric pollution, for example transport workers, garage hands and policemen. On the other hand, the results of a number of investigations have suggested that a relationship does exist between atmospheric pollution and lung cancer. Perhaps the best evidence for this relationship comes from studies of the small number of deaths from the disease among non-smokers in different types of residential district; in these studies higher death rates have been observed among non-smokers in large towns than among those in rural areas. On balance it seems likely that atmospheric pollution plays some part in causing the disease, but a relatively minor one in comparison with cigarette smoking.
Assessment of the Evidence Relating to Smoking and Lung Cancer
Knowledge of the causation of lung cancer is still incomplete. Many factors other than tobacco smoking are undoubtedly capable of producing the disease; for example, at least five industrial causes have been recognised. Nevertheless, the evidence for an association between lung cancer and tobacco smoking has been steadily mounting throughout the past 8 years and it is significant that, during the whole of this period, the most critical examination has failed to invalidate the main conclusions drawn from it. It has indeed been suggested that the fundamental cause may be some common factor underlying both the tendency to tobacco smoking and to the development of lung cancer some 25 to 50 years later, but no evidence has been produced in support of this hypothesis.
In scientific work, as in the practical affairs of everyday life, conclusions have often to be founded on the most reasonable and probable explanation of the observed facts and, so far, no adequate explanation for the large increase in the incidence of lung cancer has been advanced save that cigarette smoking is indeed the principal factor in the causation of the disease. The epidemiological evidence is now extensive and very detailed, and it follows a classical pattern upon which many advances in preventive medicine have been made in the past. It is clearly impossible to add to the evidence by means of an experiment in man. The Council are, however, supporting a substantial amount of laboratory research which may throw more light on the mechanism by which tobacco smoke and other suspected causative factors exert their effect, and which may thus eventually add to the degree of proof already attained as a result of studies of human populations. It must be emphasised, however, that negative results from work with animals cannot invalidate conclusions drawn from observations on man.
1. A very great increase has occurred during the past 25 years in the death rate from lung cancer in Great Britain and other countries.
2. A relatively small number of the total cases can be attributed to specific industrial hazards.
3. A proportion of cases, the exact extent of which cannot yet be defined, may be due to atmospheric pollution.
4. Evidence from many investigations in different countries indicates that a major part of the increase is associated with tobacco smoking, particularly in the form of cigarettes. In the opinion of the Council, the most reasonable interpretation of this evidence is that the relationship is one of direct cause and effect.
5. The identification of several carcinogenic substances in tobacco smoke provides a rational basis for such a causal relationship.
6: 12 March 1962: Enoch Powell, Minister of Health: Oral Answer
My right hon. Friend the Secretary of State for Scotland and I are asking local health authorities to use all their channels of health education to make the conclusions of the [Royal College of Physicians’] report widely known and to make clear to the public the dangers to health of smoking, particularly of cigarettes. We shall be giving them guidance and providing them with publicity material. We are also consulting with the Central and Scottish Councils for Health Education about ways in which they can help. As regards health education in the schools, my right hon. Friend the Minister of Education is answering a Question today.
In answer to supplementary questions, Mr Powell said:
There is no direct comparability between the sum spent by local health authorities and the sums spent on advertising.
[T]his report is undoubtedly an extremely valuable and powerful weapon in the hands of health education which the Government will now be actively supporting. The other suggestions made in the report of the Royal College are under consideration by the Government.
I shall be providing local health authorities with free publicity material, and I shall be in consultation with them and with the Central Council for Health Education as to the most effective form which that material might take. I have under consideration the suggestion of anti-smoking clinics which is made in the Royal College’s report. I have in mind that experiments might be made in that direction.
The Government certainly accept that the report demonstrates authoritatively and crushingly the causal connection between smoking and lung cancer and the more general hazards to health of smoking.
The question of television advertising, as of advertising generally, is dealt with in the suggestions made in the report which, as I have said, are under consideration by the Government. I have no doubt, however, that, apart from the steps to be taken by my right hon. Friend the Minister of Education, the health education work of local health authorities will have young people very much in mind. Health education work is undoubtedly one of the most effective channels for getting this message over in the right places, and I shall certainly give it every support I can.