BRITISH MEDICAL JOURNAL
5 AUGUST 1978
myocardial infarction so that any arrhythmia that developed could be treated promptly. However, there is evidence that hospital care may actually cause some of the arrhythmias that then have to be treated. More than 20 years ago Dr Klaus Jarvinen' observed that a disproportionate number of patients dying in hospital after acute myocardial infarction did so during or shortly after ward rounds. That interaction with hospitals and staff can significantly affect a patient's heart rate and rhythm is also well documented.2 Although no one would suggest that there is no place for specialised coronary care units it is tempting to speculate that they have to be so well equipped and expertly staffed to compensate for the arrhythmias precipitated by the fear and isolation experienced by a patient in hospital. A study comparing the incidence of arrhythmias after myocardial infarction at home and in hospital would be most interesting. JAMES COX Department of Family Practice, Southern Illinois University School
of Medicine, Springfield, Illinois
Jarvinen, Thomas,
K A, British Medical journal, 1955, 1, 318. S A, Lynch, J J, and Mills, M E, Heart and Lung, 1975, 4, 746. 3Lynch, J J, et al, American Heart Jrournal, 1977, 93, 645.
I
2
Metoclopramide in young children SIR,-Metoclopramide is frequently used for symptomatic relief of nausea and vomiting.1-4 Toxic effects which are unpleasant and alarming are prevalent in children. The margin between therapeutic and toxic dosage is narrow and we would like to draw attention to the care necessary in prescribing metoclopramide and instructing parents in the administration of this drug by reporting two cases of children who required admission to hospital following "convulsions." A 10-month-old child was prescribed metoclopramide 1 mg four times daily by her general practitioner, having presented with a two-day history of diarrhoea and vomiting. She received three doses within a 12-h period, after which she became hypertonic and exhibited intermittent opisthotonos. A girl aged 2 years 9 months who had been vomiting for four days presented with generalised hypertonia, having had an oculogyric crisis. It became clear later that this child had been prescribed a metoclopramide paediatric liquid preparation (1 mg in 5 ml) at the onset of her illness and had received eight doses over 48 h followed by eight doses of a metoclopramide syrup preparation containing 5 mg in 5 ml which had been prescribed for her sister, who had similar symptoms. In both of these children the effects lasted less than 24 h. Neither was treated actively for the side effects of metoclopramide.
The doses of metoclopramide these children had received were both in excess of the manufacturer's recommendations.5 The first child had merely received 3 mg in 12 h (0-6 mg/ kg/24 h) compared with the manufacturer's recommendation of 0 5 mg/kg/24 h, while the second child had received initially 8 mg within 48 h in eight doses (0 33 mg/kg/24 h) and a further 40 mg in eight doses over the 48 h before admission (1 66 mg/kg/24 h). In the second case the overdosage was due to parental confusion with the two different strengths of the preparations, which have an identical colour. It should be remembered that a four times daily or six-hourly prescription
431
may result in three doses being given in 12 h and five doses within the 24-h period. Particular care is required when prescribing metoclopramide preparations for children, as the extrapyramidal side effects may occur not only with an accidental overdose but also with very minimal overdosage, as demonstrated in the first case. The side effects may present as a "convulsion" and thus lead to an unnecessary hospital admission. Instructions to parents should be clear and emphasis given to the care necessary to avoid exceeding the prescribed dose, particularly when different preparations of metoclopramide are present in the same house. J A SILLS E J GLASS Royal Hospital for Sick Children,
Edinburgh
'Melmed, S, and Bank, H, British Medical Jrournal, 1975, 1, 331. 2 Van Daele, M C, Archives of Disease in Childhood, 3 4
1970, 45, 130. Cochlin, D L, British J7ournal of Clinical Practice, 1974, 28, 201. Nimmo, W S, Prescribers'3Journal, 1977, 17, 90. Association of the British Pharmaceutical Industry, Data Sheet Compendium, 1977, p 83. London, ABPI, 1977.
Housing, health, and illness
allergic illness. Otherwise my view about "dampness" being a "lesser factor" coincides with Dr Gray's. My work in assisting the DCP phased out as younger medical help became available, but I am sorry that it is not now possible routinely to home visit but necessary to rely on GPs' reports. One hopes that if the GP could not pay a recent home visit he will have obtained reports from health visitors and/or social workers before making his recommendation to the housing medical officer. F JOHN G LISHMAN
Salisbury, Wilts
SIR,-With reference to Dr J A Muir Gray's article (8 July, p 100) we would like to make the following comments. Dr Muir Gray's observations and inferences are limited by the small number of applications which he received for rehousing on medical grounds in one year (612 cases). Our problems are much greater in that we receive over 10 000 applications for medical rehousing in Liverpool in a year, and from them 600 cases can be given priority on medical grounds and these alone are nearly equal to his total number of cases. In addition, applicants who are already in local authority housing (high-rise flats, etc) may receive medical points towards their transfer to more suitable local authority accommodation. The 60' of cases which receive medical priority may compete in some parts of the city with slum clearance cases and therefore their rehousing may be delayed. Despite this, we still believe that medical intervention is effective and efficient. A community physician has to spend three hours a day dealing on average with 60 cases and at the end of the week he has to decide the 12 worst cases for priority decision from 300 cases, in addition to giving transfer points. This type of ceiling effect is necessary, particularly when one is faced with the problem of limited resources (and in fact a generous allocation by the council). We agree with Dr Muir Gray's recommendations for classes IV and V to some extent, but regarding class III we do not consider this to be a priority group as we believe that social and mental stresses are multifactorial in origin and rehousing alone may not solve the problem. Nevertheless, isolated social cases of extreme urgency have been given priority on medical grounds on some occasions. DAVID S PICKUP S P MOOKERJEE
SIR,-I write to commend Dr J A Muir Gray's conclusion (8 July, p 100) that poor housing is a "major public health problem." In his work of medically assessing priority Dr Gray has five points available, but out of what total ? Salisbury District Council's points scheme has 80 available points, of which a maximum of 20 are reserved for medical priorities. Although Dr Gray can spare only 30 minutes a day for housing, could he not adjust his points for urgency instead of allocating five to all alike ? Until April 1974 I was medical officer of health to three district councils and clinical medical officer to Wiltshire County Council. After reorganisation I, along with other doctors, was transferred to the Wiltshire Area Health Authority, being "latched on" half time to the district community physician for the Salisbury Health District. My nonclinical work, apart from occasions when I deputised for the DCP in office matters, consisted in assessing medical priority for housing. When I was district MOH the local authorities relied on me to assess such priority by personal visits. Sometimes more than one visit was needed, an evening visit being helpful especially when mental health was involved, as was common. Information from general Liverpool Area Health Authority (T), practitioners, health visitors, social workers, or Liverpool public health inspectors was helpful. A confidential copy of my assessment report was routinely sent to the GP. After transfer to the Screening for breast cancer AHA I continued my housing priority assessments similarly. SIR,-While in no way wishing to dissociate Dr Gray's cases of "severe handicap" myself from the statement on screening for need answers to questions such as "Is there breast cancer by the British Breast Group another person in the home to help ?" (for (15 July, p 175), which is a fair and factual example, emptying the commode of a bed- account of what transpired at a meeting to ridden elderly person); "Is there a home help review the subject at the Imperial Cancer or a home nurse attending daily ?"; "Are Fund, I wish to make it clear that at least one children involved ?" These essentials can be member of the group believes that the case in most quickly ascertained by a home visit, but if favour of screening remains unproved. The this is impossible reports from health visitors basic assumption behind all efforts for the and social workers are needed before deciding early detection of carcinoma of the breast is to allocate 0-20 medical points. that the longer the cancer remains untreated Regarding "dampness," if house mites the more likely it is to disseminate. It would breed more freely, so do moulds or fungi, therefore seem reasonable that detecting spores of which can cause respiratory and other cancers during the phase when they are radio-
432
logically detectable but clinically impalpable would save more lives than waiting for the tumours to reach clinically detectable proportions. However, as I have previously pointed out in the pages of this journal,' the period during which a breast cancer is radiologically detectable but impalpable is likely to be a relatively short one in the overall natural history of the disease. Mass screening therefore may benefit only a minority of all cases. None the less, it is a reasonable hypothesis to be tested. The only concrete evidence available that screening can save lives comes from one controlled trial referred to as the Health Insurance Plan (HIP) study.2 It would surely be foolhardy to base a worldwide change of strategy on this one experiment. It is true that the Department of Health has decided to institute a programme to compare the mortality rates from carcinoma of the breast in geographically defined areas, comparing a screened population with a population offered routine service only. To my mind this is a very second-rate approach and I would have much preferred to see a repetition of an HIP-type study in Britain. In the absence of mortality data from screened and unscreened control populations the value of the technique could be indirectly inferred by comparing the proportion of cancers of the more favourable stages that are detected. Looked upon in this way the early results from the Edinburgh Breast Screening Clinic published in the same issue (p 175) as the British Breast Group statement make interesting reading. Of the 18 cancers detected, three were non-invasive and it is by no means certain that the natural history of these pathological entities is to progress into frankly invasive cancer. However, accepting that this would be the inevitable course if left untreated, we are left with 12 cases that were histologically node-negative. Somewhat surprisingly six, or precisely one-third of the cancers detected, had involvement of the lymph nodes. These cases might indeed be chronologically early, but biologically they are late, leaving the woman with every likelihood of residual micrometastases.3 It is therefore strictly relevant to compare the nodal status of breast cancers presenting in the conventional manner to the same clinic as reported in the Lancet in 1975.4 Here 18 out of 38 patients described in a study of axillary node sampling at the time of mastectomy had positive lymph nodes-that is, approximately one in two. In order to assess the cost-effectiveness of screening for breast cancer it is not sufficient to quote the cost for each cancer detected. The only meaningful figure is that calculated for each life saved as a result of the screening programme. Assuming therefore that each additional node-negative case detected in a screening programme is equivalent to a life saved, it can be calculated from the preceding figures that for every six cancers detected at a screening programme one additional nodenegative case is found. If it costs £6000 to detect each cancer, then it costs £36 000 to detect each additional node-negative case. Far be it from me to place a value on a woman's life, as even the Book of Proverbs (xxxi, 10) prices the ideal wife far above rubies, but in these days of swingeing cutbacks in the national health care budget it is not too difficult to imagine how the expenditure of £36 000 could benefit more than one woman suffering with carcinoma of the breast. The total budget for the Cancer Research Campaign trial, the largest ever undertaken to
BRITISH MEDICAL JOURNAL
investigate the management of breast cancer, was of this order.5 There are so many burning questions yet to be answered concerning the management of this commonest of all female malignancies-for example, the role of adjuvant chemotherapy or adjuvant endocrine therapy, the place of breast conservation, the interaction between local and systemic therapies, etc-that only prospective clinical trials are likely to answer that I for one feel that a national trials programme would improve the survival rates and the quality of life of infinitely more women than a national screening programme. However, I am prepared to change my stance, but only on the basis of hard data coming out of the mortality statistics from the proposed Department of Health studies. Until that time anyone who takes a position either for or against screening for carcinoma of the breast is being ruled by his heart rather than his head. MICHAEL BAUM Department of Surgery, Welsh National School of Medicine, Cardiff IBaum, M, British Medical3Journal, 1976, 1, 439. 2Strax, P, et al, Cqncer, 1967, 20, 2184. 3Fisher, E R, et al, Cancer, 1975, 36, 1. Cant, E L M, Shivas, A A, and Forrest, A P M, Lancet, 1975, 1, 995. 6C R C Working Party, British Medical Journal, 1976, 1, 1035.
SIR,-The latest statement by the British Breast Group (15 July, p 178) provides a most useful note on screening for breast cancer. There are a number of points that require further probing before a desirable strategy for work in Britain can be spelled out. On the question of the effectiveness of screening the statement appears to place emphasis on the need for further randomised controlled trials, though acknowledging that other controlled studies such as are proposed in Britain can yield useful information. It would be helpful to have more detailed discussion of the various approaches to setting up trials, the specific constraints from alternative study designs, and the qualifications in data collection that would be required in order to achieve interpretable results. In identifying "women likely to benefit from screening" it might be useful to distinguish (1) those who are at high risk of developing breast cancer, and within this group those at risk of developing lesions in which early diagnosis will influence prognosis; and also (2) those who need and would benefit from the reassurance given by a negative screening result. Research on risk categorisation could be aimed at identifying different stages in the development of breast cancer such as (a) markers of risk that are independent of carcinogenic mechanisms (for example, social class), (b) aetiological factors (for example, age at first pregnancy), (c) possible precursors of malignant change (for example, duct pattern, hormonal factors), and (d) preinvasive disease or possible functional changes indicating incipient disease (for example, tumour markers). As mentioned in the statement, health education in breast self-examination requires a full evaluation, but the role of education in screening programmes also deserves further study in order to identify appropriate ways of boosting response. In addition to the possible adverse effects listed, others to be considered include (1) the anxiety and morbidity engendered by "unnecessary" biopsies, (2) the possibility that subsequent symptoms may be ignored in
5 AUGUST 1978
women negative at screening, (3) long-term psychological effects of repeated cycles of tension and relief which may occur before and after regular self-examination or screening, and (4) the danger that in some women screening may merely prolong the time for which a woman knows she has malignant disease without influencing ultimate survival. These are just some of the areas which may merit further research, and current studies of early detection programmes offer an opportunity for exploring these issues.
MICHAEL ALDERSON JOCELYN CHAMBERLAIN Division of Epidemiology, Institute of Cancer Research: Royal Cancer Hospital, Sutton, Surrey
Domiciliary oxygen SIR,-We were interested in the paper by Dr M M Jones and others (27 May, p 1397) covering the domiciliary use of oxygen. In 1977 we carried out a similar survey of oxygen use in Sheffield and discovered very similar patterns of consumption. We interviewed 34 patients in their homes drawn from a random list of NHS patients across the city; they were mainly bronchitics. Three had stopped using oxygen before the visit; one was an MRC trialist using oxygen for 15 h a day, while one achieved 6-7 h daily and one 3-4 h daily. Three patients used oxygen on a regular basis for short periods only and the remaining 25 patients used oxygen only for short periods and only when they felt that their breathlessness demanded it. The average six-monthly cylinder consumption rate varied between 168 and 0 3, with a mean of 16 6 for the whole group, and 6 5 for the 25 using oxygen for short periods only. We also found that current supply arrangements were adequate for the limited quantities used, that in general patients were satisfied with the service, and that most patients reported subjective benefit. We took the opportunity to measure oxygen flbw rates delivered by the drug-tariff reducing valves and found them to be remarkably pressure-sensitive. Thirty-one valves were tested. On the higher setting cylinders either three-quarters or entirely full had a mean flow rate of 3 48 (SD 0 68) 1/min and those either half or a quarter full a mean flow rate of 2 75 (SD 0 69) 1/min. On the lower setting the means were respectively 2 22 (SD 0 32) and 1 56 (SD 0 46) 1/min. These differences are statistically significant. As the cylinder empties the patient receives less oxygen and clearly a better product is essential. Domiciliary oxygen is expensive; oxygen for brief periods of the day has little physiological benefit and has a largely placebo effect. If the 25 patients found to be using oxygen for brief periods when breathless are considered, the mean cylinder consumption is 13 per patient per year. It will cost £97 50 per annum per patient to provide a placebo effect of this sort and we would argue this to be
unacceptably high. A number of studies' 2 have shown that long-term oxygen for sufficient periods of daily time can achieve a physiological response, but demonstration of clinical improvement awaits the results of the MRC controlled trial. Long-term oxygen therapy patients in Sheffield take their oxygen more or less as prescribed but will need in future to be carefully selected
5 AUGUST 1978
myocardial infarction so that any arrhythmia that developed could be treated promptly. However, there is evidence that hospital care may actually cause some of the arrhythmias that then have to be treated. More than 20 years ago Dr Klaus Jarvinen' observed that a disproportionate number of patients dying in hospital after acute myocardial infarction did so during or shortly after ward rounds. That interaction with hospitals and staff can significantly affect a patient's heart rate and rhythm is also well documented.2 Although no one would suggest that there is no place for specialised coronary care units it is tempting to speculate that they have to be so well equipped and expertly staffed to compensate for the arrhythmias precipitated by the fear and isolation experienced by a patient in hospital. A study comparing the incidence of arrhythmias after myocardial infarction at home and in hospital would be most interesting. JAMES COX Department of Family Practice, Southern Illinois University School
of Medicine, Springfield, Illinois
Jarvinen, Thomas,
K A, British Medical journal, 1955, 1, 318. S A, Lynch, J J, and Mills, M E, Heart and Lung, 1975, 4, 746. 3Lynch, J J, et al, American Heart Jrournal, 1977, 93, 645.
I
2
Metoclopramide in young children SIR,-Metoclopramide is frequently used for symptomatic relief of nausea and vomiting.1-4 Toxic effects which are unpleasant and alarming are prevalent in children. The margin between therapeutic and toxic dosage is narrow and we would like to draw attention to the care necessary in prescribing metoclopramide and instructing parents in the administration of this drug by reporting two cases of children who required admission to hospital following "convulsions." A 10-month-old child was prescribed metoclopramide 1 mg four times daily by her general practitioner, having presented with a two-day history of diarrhoea and vomiting. She received three doses within a 12-h period, after which she became hypertonic and exhibited intermittent opisthotonos. A girl aged 2 years 9 months who had been vomiting for four days presented with generalised hypertonia, having had an oculogyric crisis. It became clear later that this child had been prescribed a metoclopramide paediatric liquid preparation (1 mg in 5 ml) at the onset of her illness and had received eight doses over 48 h followed by eight doses of a metoclopramide syrup preparation containing 5 mg in 5 ml which had been prescribed for her sister, who had similar symptoms. In both of these children the effects lasted less than 24 h. Neither was treated actively for the side effects of metoclopramide.
The doses of metoclopramide these children had received were both in excess of the manufacturer's recommendations.5 The first child had merely received 3 mg in 12 h (0-6 mg/ kg/24 h) compared with the manufacturer's recommendation of 0 5 mg/kg/24 h, while the second child had received initially 8 mg within 48 h in eight doses (0 33 mg/kg/24 h) and a further 40 mg in eight doses over the 48 h before admission (1 66 mg/kg/24 h). In the second case the overdosage was due to parental confusion with the two different strengths of the preparations, which have an identical colour. It should be remembered that a four times daily or six-hourly prescription
431
may result in three doses being given in 12 h and five doses within the 24-h period. Particular care is required when prescribing metoclopramide preparations for children, as the extrapyramidal side effects may occur not only with an accidental overdose but also with very minimal overdosage, as demonstrated in the first case. The side effects may present as a "convulsion" and thus lead to an unnecessary hospital admission. Instructions to parents should be clear and emphasis given to the care necessary to avoid exceeding the prescribed dose, particularly when different preparations of metoclopramide are present in the same house. J A SILLS E J GLASS Royal Hospital for Sick Children,
Edinburgh
'Melmed, S, and Bank, H, British Medical Jrournal, 1975, 1, 331. 2 Van Daele, M C, Archives of Disease in Childhood, 3 4
1970, 45, 130. Cochlin, D L, British J7ournal of Clinical Practice, 1974, 28, 201. Nimmo, W S, Prescribers'3Journal, 1977, 17, 90. Association of the British Pharmaceutical Industry, Data Sheet Compendium, 1977, p 83. London, ABPI, 1977.
Housing, health, and illness
allergic illness. Otherwise my view about "dampness" being a "lesser factor" coincides with Dr Gray's. My work in assisting the DCP phased out as younger medical help became available, but I am sorry that it is not now possible routinely to home visit but necessary to rely on GPs' reports. One hopes that if the GP could not pay a recent home visit he will have obtained reports from health visitors and/or social workers before making his recommendation to the housing medical officer. F JOHN G LISHMAN
Salisbury, Wilts
SIR,-With reference to Dr J A Muir Gray's article (8 July, p 100) we would like to make the following comments. Dr Muir Gray's observations and inferences are limited by the small number of applications which he received for rehousing on medical grounds in one year (612 cases). Our problems are much greater in that we receive over 10 000 applications for medical rehousing in Liverpool in a year, and from them 600 cases can be given priority on medical grounds and these alone are nearly equal to his total number of cases. In addition, applicants who are already in local authority housing (high-rise flats, etc) may receive medical points towards their transfer to more suitable local authority accommodation. The 60' of cases which receive medical priority may compete in some parts of the city with slum clearance cases and therefore their rehousing may be delayed. Despite this, we still believe that medical intervention is effective and efficient. A community physician has to spend three hours a day dealing on average with 60 cases and at the end of the week he has to decide the 12 worst cases for priority decision from 300 cases, in addition to giving transfer points. This type of ceiling effect is necessary, particularly when one is faced with the problem of limited resources (and in fact a generous allocation by the council). We agree with Dr Muir Gray's recommendations for classes IV and V to some extent, but regarding class III we do not consider this to be a priority group as we believe that social and mental stresses are multifactorial in origin and rehousing alone may not solve the problem. Nevertheless, isolated social cases of extreme urgency have been given priority on medical grounds on some occasions. DAVID S PICKUP S P MOOKERJEE
SIR,-I write to commend Dr J A Muir Gray's conclusion (8 July, p 100) that poor housing is a "major public health problem." In his work of medically assessing priority Dr Gray has five points available, but out of what total ? Salisbury District Council's points scheme has 80 available points, of which a maximum of 20 are reserved for medical priorities. Although Dr Gray can spare only 30 minutes a day for housing, could he not adjust his points for urgency instead of allocating five to all alike ? Until April 1974 I was medical officer of health to three district councils and clinical medical officer to Wiltshire County Council. After reorganisation I, along with other doctors, was transferred to the Wiltshire Area Health Authority, being "latched on" half time to the district community physician for the Salisbury Health District. My nonclinical work, apart from occasions when I deputised for the DCP in office matters, consisted in assessing medical priority for housing. When I was district MOH the local authorities relied on me to assess such priority by personal visits. Sometimes more than one visit was needed, an evening visit being helpful especially when mental health was involved, as was common. Information from general Liverpool Area Health Authority (T), practitioners, health visitors, social workers, or Liverpool public health inspectors was helpful. A confidential copy of my assessment report was routinely sent to the GP. After transfer to the Screening for breast cancer AHA I continued my housing priority assessments similarly. SIR,-While in no way wishing to dissociate Dr Gray's cases of "severe handicap" myself from the statement on screening for need answers to questions such as "Is there breast cancer by the British Breast Group another person in the home to help ?" (for (15 July, p 175), which is a fair and factual example, emptying the commode of a bed- account of what transpired at a meeting to ridden elderly person); "Is there a home help review the subject at the Imperial Cancer or a home nurse attending daily ?"; "Are Fund, I wish to make it clear that at least one children involved ?" These essentials can be member of the group believes that the case in most quickly ascertained by a home visit, but if favour of screening remains unproved. The this is impossible reports from health visitors basic assumption behind all efforts for the and social workers are needed before deciding early detection of carcinoma of the breast is to allocate 0-20 medical points. that the longer the cancer remains untreated Regarding "dampness," if house mites the more likely it is to disseminate. It would breed more freely, so do moulds or fungi, therefore seem reasonable that detecting spores of which can cause respiratory and other cancers during the phase when they are radio-
432
logically detectable but clinically impalpable would save more lives than waiting for the tumours to reach clinically detectable proportions. However, as I have previously pointed out in the pages of this journal,' the period during which a breast cancer is radiologically detectable but impalpable is likely to be a relatively short one in the overall natural history of the disease. Mass screening therefore may benefit only a minority of all cases. None the less, it is a reasonable hypothesis to be tested. The only concrete evidence available that screening can save lives comes from one controlled trial referred to as the Health Insurance Plan (HIP) study.2 It would surely be foolhardy to base a worldwide change of strategy on this one experiment. It is true that the Department of Health has decided to institute a programme to compare the mortality rates from carcinoma of the breast in geographically defined areas, comparing a screened population with a population offered routine service only. To my mind this is a very second-rate approach and I would have much preferred to see a repetition of an HIP-type study in Britain. In the absence of mortality data from screened and unscreened control populations the value of the technique could be indirectly inferred by comparing the proportion of cancers of the more favourable stages that are detected. Looked upon in this way the early results from the Edinburgh Breast Screening Clinic published in the same issue (p 175) as the British Breast Group statement make interesting reading. Of the 18 cancers detected, three were non-invasive and it is by no means certain that the natural history of these pathological entities is to progress into frankly invasive cancer. However, accepting that this would be the inevitable course if left untreated, we are left with 12 cases that were histologically node-negative. Somewhat surprisingly six, or precisely one-third of the cancers detected, had involvement of the lymph nodes. These cases might indeed be chronologically early, but biologically they are late, leaving the woman with every likelihood of residual micrometastases.3 It is therefore strictly relevant to compare the nodal status of breast cancers presenting in the conventional manner to the same clinic as reported in the Lancet in 1975.4 Here 18 out of 38 patients described in a study of axillary node sampling at the time of mastectomy had positive lymph nodes-that is, approximately one in two. In order to assess the cost-effectiveness of screening for breast cancer it is not sufficient to quote the cost for each cancer detected. The only meaningful figure is that calculated for each life saved as a result of the screening programme. Assuming therefore that each additional node-negative case detected in a screening programme is equivalent to a life saved, it can be calculated from the preceding figures that for every six cancers detected at a screening programme one additional nodenegative case is found. If it costs £6000 to detect each cancer, then it costs £36 000 to detect each additional node-negative case. Far be it from me to place a value on a woman's life, as even the Book of Proverbs (xxxi, 10) prices the ideal wife far above rubies, but in these days of swingeing cutbacks in the national health care budget it is not too difficult to imagine how the expenditure of £36 000 could benefit more than one woman suffering with carcinoma of the breast. The total budget for the Cancer Research Campaign trial, the largest ever undertaken to
BRITISH MEDICAL JOURNAL
investigate the management of breast cancer, was of this order.5 There are so many burning questions yet to be answered concerning the management of this commonest of all female malignancies-for example, the role of adjuvant chemotherapy or adjuvant endocrine therapy, the place of breast conservation, the interaction between local and systemic therapies, etc-that only prospective clinical trials are likely to answer that I for one feel that a national trials programme would improve the survival rates and the quality of life of infinitely more women than a national screening programme. However, I am prepared to change my stance, but only on the basis of hard data coming out of the mortality statistics from the proposed Department of Health studies. Until that time anyone who takes a position either for or against screening for carcinoma of the breast is being ruled by his heart rather than his head. MICHAEL BAUM Department of Surgery, Welsh National School of Medicine, Cardiff IBaum, M, British Medical3Journal, 1976, 1, 439. 2Strax, P, et al, Cqncer, 1967, 20, 2184. 3Fisher, E R, et al, Cancer, 1975, 36, 1. Cant, E L M, Shivas, A A, and Forrest, A P M, Lancet, 1975, 1, 995. 6C R C Working Party, British Medical Journal, 1976, 1, 1035.
SIR,-The latest statement by the British Breast Group (15 July, p 178) provides a most useful note on screening for breast cancer. There are a number of points that require further probing before a desirable strategy for work in Britain can be spelled out. On the question of the effectiveness of screening the statement appears to place emphasis on the need for further randomised controlled trials, though acknowledging that other controlled studies such as are proposed in Britain can yield useful information. It would be helpful to have more detailed discussion of the various approaches to setting up trials, the specific constraints from alternative study designs, and the qualifications in data collection that would be required in order to achieve interpretable results. In identifying "women likely to benefit from screening" it might be useful to distinguish (1) those who are at high risk of developing breast cancer, and within this group those at risk of developing lesions in which early diagnosis will influence prognosis; and also (2) those who need and would benefit from the reassurance given by a negative screening result. Research on risk categorisation could be aimed at identifying different stages in the development of breast cancer such as (a) markers of risk that are independent of carcinogenic mechanisms (for example, social class), (b) aetiological factors (for example, age at first pregnancy), (c) possible precursors of malignant change (for example, duct pattern, hormonal factors), and (d) preinvasive disease or possible functional changes indicating incipient disease (for example, tumour markers). As mentioned in the statement, health education in breast self-examination requires a full evaluation, but the role of education in screening programmes also deserves further study in order to identify appropriate ways of boosting response. In addition to the possible adverse effects listed, others to be considered include (1) the anxiety and morbidity engendered by "unnecessary" biopsies, (2) the possibility that subsequent symptoms may be ignored in
5 AUGUST 1978
women negative at screening, (3) long-term psychological effects of repeated cycles of tension and relief which may occur before and after regular self-examination or screening, and (4) the danger that in some women screening may merely prolong the time for which a woman knows she has malignant disease without influencing ultimate survival. These are just some of the areas which may merit further research, and current studies of early detection programmes offer an opportunity for exploring these issues.
MICHAEL ALDERSON JOCELYN CHAMBERLAIN Division of Epidemiology, Institute of Cancer Research: Royal Cancer Hospital, Sutton, Surrey
Domiciliary oxygen SIR,-We were interested in the paper by Dr M M Jones and others (27 May, p 1397) covering the domiciliary use of oxygen. In 1977 we carried out a similar survey of oxygen use in Sheffield and discovered very similar patterns of consumption. We interviewed 34 patients in their homes drawn from a random list of NHS patients across the city; they were mainly bronchitics. Three had stopped using oxygen before the visit; one was an MRC trialist using oxygen for 15 h a day, while one achieved 6-7 h daily and one 3-4 h daily. Three patients used oxygen on a regular basis for short periods only and the remaining 25 patients used oxygen only for short periods and only when they felt that their breathlessness demanded it. The average six-monthly cylinder consumption rate varied between 168 and 0 3, with a mean of 16 6 for the whole group, and 6 5 for the 25 using oxygen for short periods only. We also found that current supply arrangements were adequate for the limited quantities used, that in general patients were satisfied with the service, and that most patients reported subjective benefit. We took the opportunity to measure oxygen flbw rates delivered by the drug-tariff reducing valves and found them to be remarkably pressure-sensitive. Thirty-one valves were tested. On the higher setting cylinders either three-quarters or entirely full had a mean flow rate of 3 48 (SD 0 68) 1/min and those either half or a quarter full a mean flow rate of 2 75 (SD 0 69) 1/min. On the lower setting the means were respectively 2 22 (SD 0 32) and 1 56 (SD 0 46) 1/min. These differences are statistically significant. As the cylinder empties the patient receives less oxygen and clearly a better product is essential. Domiciliary oxygen is expensive; oxygen for brief periods of the day has little physiological benefit and has a largely placebo effect. If the 25 patients found to be using oxygen for brief periods when breathless are considered, the mean cylinder consumption is 13 per patient per year. It will cost £97 50 per annum per patient to provide a placebo effect of this sort and we would argue this to be
unacceptably high. A number of studies' 2 have shown that long-term oxygen for sufficient periods of daily time can achieve a physiological response, but demonstration of clinical improvement awaits the results of the MRC controlled trial. Long-term oxygen therapy patients in Sheffield take their oxygen more or less as prescribed but will need in future to be carefully selected
