296
Screening
for breast
cancer
SIR,-As a result of the Forrest report,’ a nationwide breast screening programme has been introduced in the UK. This report recommended that women between ages fifty and sixty-four years should be screened by a single oblique mammogram at three-year intervals. The report states that two views would increase the cost by 29%. We feel that the Forrest report overstated the difference in cost between a single and two view approach. We are presently taking two views with no reduction in throughput. We estimate that the increase in cost will be L15000 annually (film, and processing costs). For a total catchment population of 54 000 women and an annual revenue allocation of L250 000 it is a small expenditure that may be offset by fewer recalls for assessment and a higher cancer detection rate.2-4 A reduction in the number of recalls would be welcome not only financially but also to lessen anxiety in healthy women.
A survey of the forty-eight screening units that were operational by mid-November, 1989, was undertaken to establish practice with respect to the Forrest single-view recommendation. Forty-three (90%) replies were received. Fifteen centres (35%) were taking two views routinely and twenty-eight (65%) were adhering to the Forrest guidelines of a single oblique view. It is essential that the radiologist is satisfied with the examination, but our findings indicate that 35% of UK radiologists participating in the breast screening programme find single-view mammography unacceptable and have departed from the Forrest guidelines. The programme is carefully audited. The analysis of statistics especially with respect to call/recall rates should take into account this fundamental difference in practice. We are not aware that the extent of this discrepancy in practice has hitherto been noted. Northern Ireland Screening Programmes, 12-22 Linenhall Street, Belfast BT2 8BS, UK
A. J. O’DOHERTY PHILIP DONAGHY
Department of Health and Social Security. Breast cancer screening (Forrest report). London: HM Stationery Office, 1986. 2. Muir BB, Kirkpatrick AE, Roberts MM, Duffy SW. Oblique view mammography: adequacy for screening. Radiology 1984; 151: 39-41. 3. Sickles EA, Weber WN, Galvin HB, Ominsky SH, Solitto RA. Baseline screening mammography. one versus two views per breast. AJR 1986; 147: 1149-53. 1.
4. Basset
LW, Bunnell DH, Jahanshahi R, Gold RH, Amdt RD, Linsman J. detection: one versus two views. Radiology 1987; 165: 95-97.
owns
comment.
Update Computers,
ABRAHAM MARCUS
London WC1 E 7EA, UK
Computer-assisted diagnosis SiR,—Your Dec 9 editorial appropriately emphasises the fundamental differences between the skilled clinician and even the best computer program. However, treatable and curable diagnosis are overlooked by physicians, especially in rare or newly described diseases and unusual presentations of more common illnesses. To minimise these errors, diagnostic prompting may be useful, although this remains to be proved by outcome studies. Four systems (three in internal medicine, one in paediatrics), in addition to the two you mention, have been described and subjected to testing with some degree of rigour.1-4 In puzzling cases the computer, using mathematical logic, can include the correct diagnosis on a list of possibilities in most instances. Even at its present stage of development, diagnostic prompting by computer may help the clinician in the occasional but important perplexing case. Department of Medicine, Albert Einstein Medical Center and Temple University School of Medicine, Philadelphia, Pennsylvania 19141, USA
HERBERT S. WAXMAN
1. Wexler JR, Swendler PT, Tunnessen WW, Oski FA. Impact of a system of computer-assisted diagnosis. AmJ Dis Child 1975; 129: 203-05. 2. Nelson SJ, Blois MS, Tuttle MS, Erlbaum M, Harrison P, Kin H, Winkelmann B, Yamashita D. Evaluating RECONSIDER, a computer program for diagnostic prompting. J Med Systems 1985; 9: 379-88 3. Bamett GO, Cimino JJ, Hupp JA, Hoffer EP. DXplain: an evolving diagnostic decision-support system. JAm Med Assoc 1987; 258: 67-74. 4. Hammersley JR, Cooney K. Evaluating the utility of available differential diagnosis systems Proceedings of the Twelfth Annual Symposium on Computer Applications in Medical Care. Washington. IEEE Computer Society Press, 1988 229-31.
Breast
cancer
Who
cash for the support of education and research in general practice and administration. The question "who owns patients’ data?" may offer the lawyers material for argument. The definition of public interest in this particular situation, however, may not seem so elusive to many, including patients whose rights have been ignored in Mrs Brahams’
patients’ data?
SiR,—In her discussion of the ownership of patients’ data obtained from general practice computers your legal correspondent Diana Brahams (Jan 6, p 39) does not consider the parliamentary written answer by Roger Freeman, one of the Health Ministers, on Nov 28, 1989. In this statement Freeman declared the Government’s intention, as from April 1, 1990, to reimburse directly half the cost of a computer system. There had already been an announcement of the reimbursement of half the cost of support and maintenance. Freeman also said that the balance of the cost of a system will be reimbursed indirectly. These provisions would be backdated to April, 1989, and are likely to cost the Government about 50 million. There are 1800 free systems, not 2500, as Brahams says. Computerisation of the remaining practices (over 8000) within a few years will have been heavily subsidised by the Government. The issue of the disposal of patients’ data to third parties therefore takes on a different dimension. Government policy in effect provides a basis for setting up a national system of drug monitoring and post-marketing surveillance (PMS) that would include at least 85% of patients in general practice. The patient base would meet more adequately the statistical requirements for PMS, to which you refer in your Nov 4 (p 1078) editorial, and would cover risks far less frequent than the 1 in 2000 that commercial groups can at best offer. A national system would also be less costly to the pharmaceutical industry, and would more directly be, and clearly be seen to be, in the public interest, and, as you point out, likely to provide surplus
Fear of crime SIR,-Mr Watts (Jan 13, p 116) suggests that the Home Office report on fear of crime was "misleading" in recording the average chance of being mugged as 1-8% per annum in the UK. I was the only medical member of the working party that compiled the report and, as a psychiatrist, had a special interest in the psychological aspects. The risk estimates cited were the best available from Home Office statistics. As Watts suggests, there are various factors that may determine the chances of being assaulted, and there are several ways in which these might change if conditions were altered. However, this does not make the figure misleading. The working party emphasised that the quality of life of many people is greatly impaired by their fear of crime, so that, for instance, they might not go out to any event after dark. But it was also noted that the groups most apprehensive of street violence are not those mostly likely to be affected by it. This is one reason why the proportion of the population who are apprehensive of mugging is very considerably greater than the proportion who might experience such assault. The working party’s conclusion was that the encouragement of as many people as possible to use public space freely would be one of the most effective ways of reducing both actual mugging and people’s fear of it. This seems to be the opposite view to that of Watts who, I hope, is not suggesting that the working party "condoned" a risk of 1 % or indeed any other risk. The working party’s remit was to advise on how fear of crime might be reduced, which is what it did. British Journal of Psychiatry, Royal College of Psychiatrists, London SW1X 8PG, UK
HUGH FREEMAN
Screening
for breast
cancer
SIR,-As a result of the Forrest report,’ a nationwide breast screening programme has been introduced in the UK. This report recommended that women between ages fifty and sixty-four years should be screened by a single oblique mammogram at three-year intervals. The report states that two views would increase the cost by 29%. We feel that the Forrest report overstated the difference in cost between a single and two view approach. We are presently taking two views with no reduction in throughput. We estimate that the increase in cost will be L15000 annually (film, and processing costs). For a total catchment population of 54 000 women and an annual revenue allocation of L250 000 it is a small expenditure that may be offset by fewer recalls for assessment and a higher cancer detection rate.2-4 A reduction in the number of recalls would be welcome not only financially but also to lessen anxiety in healthy women.
A survey of the forty-eight screening units that were operational by mid-November, 1989, was undertaken to establish practice with respect to the Forrest single-view recommendation. Forty-three (90%) replies were received. Fifteen centres (35%) were taking two views routinely and twenty-eight (65%) were adhering to the Forrest guidelines of a single oblique view. It is essential that the radiologist is satisfied with the examination, but our findings indicate that 35% of UK radiologists participating in the breast screening programme find single-view mammography unacceptable and have departed from the Forrest guidelines. The programme is carefully audited. The analysis of statistics especially with respect to call/recall rates should take into account this fundamental difference in practice. We are not aware that the extent of this discrepancy in practice has hitherto been noted. Northern Ireland Screening Programmes, 12-22 Linenhall Street, Belfast BT2 8BS, UK
A. J. O’DOHERTY PHILIP DONAGHY
Department of Health and Social Security. Breast cancer screening (Forrest report). London: HM Stationery Office, 1986. 2. Muir BB, Kirkpatrick AE, Roberts MM, Duffy SW. Oblique view mammography: adequacy for screening. Radiology 1984; 151: 39-41. 3. Sickles EA, Weber WN, Galvin HB, Ominsky SH, Solitto RA. Baseline screening mammography. one versus two views per breast. AJR 1986; 147: 1149-53. 1.
4. Basset
LW, Bunnell DH, Jahanshahi R, Gold RH, Amdt RD, Linsman J. detection: one versus two views. Radiology 1987; 165: 95-97.
owns
comment.
Update Computers,
ABRAHAM MARCUS
London WC1 E 7EA, UK
Computer-assisted diagnosis SiR,—Your Dec 9 editorial appropriately emphasises the fundamental differences between the skilled clinician and even the best computer program. However, treatable and curable diagnosis are overlooked by physicians, especially in rare or newly described diseases and unusual presentations of more common illnesses. To minimise these errors, diagnostic prompting may be useful, although this remains to be proved by outcome studies. Four systems (three in internal medicine, one in paediatrics), in addition to the two you mention, have been described and subjected to testing with some degree of rigour.1-4 In puzzling cases the computer, using mathematical logic, can include the correct diagnosis on a list of possibilities in most instances. Even at its present stage of development, diagnostic prompting by computer may help the clinician in the occasional but important perplexing case. Department of Medicine, Albert Einstein Medical Center and Temple University School of Medicine, Philadelphia, Pennsylvania 19141, USA
HERBERT S. WAXMAN
1. Wexler JR, Swendler PT, Tunnessen WW, Oski FA. Impact of a system of computer-assisted diagnosis. AmJ Dis Child 1975; 129: 203-05. 2. Nelson SJ, Blois MS, Tuttle MS, Erlbaum M, Harrison P, Kin H, Winkelmann B, Yamashita D. Evaluating RECONSIDER, a computer program for diagnostic prompting. J Med Systems 1985; 9: 379-88 3. Bamett GO, Cimino JJ, Hupp JA, Hoffer EP. DXplain: an evolving diagnostic decision-support system. JAm Med Assoc 1987; 258: 67-74. 4. Hammersley JR, Cooney K. Evaluating the utility of available differential diagnosis systems Proceedings of the Twelfth Annual Symposium on Computer Applications in Medical Care. Washington. IEEE Computer Society Press, 1988 229-31.
Breast
cancer
Who
cash for the support of education and research in general practice and administration. The question "who owns patients’ data?" may offer the lawyers material for argument. The definition of public interest in this particular situation, however, may not seem so elusive to many, including patients whose rights have been ignored in Mrs Brahams’
patients’ data?
SiR,—In her discussion of the ownership of patients’ data obtained from general practice computers your legal correspondent Diana Brahams (Jan 6, p 39) does not consider the parliamentary written answer by Roger Freeman, one of the Health Ministers, on Nov 28, 1989. In this statement Freeman declared the Government’s intention, as from April 1, 1990, to reimburse directly half the cost of a computer system. There had already been an announcement of the reimbursement of half the cost of support and maintenance. Freeman also said that the balance of the cost of a system will be reimbursed indirectly. These provisions would be backdated to April, 1989, and are likely to cost the Government about 50 million. There are 1800 free systems, not 2500, as Brahams says. Computerisation of the remaining practices (over 8000) within a few years will have been heavily subsidised by the Government. The issue of the disposal of patients’ data to third parties therefore takes on a different dimension. Government policy in effect provides a basis for setting up a national system of drug monitoring and post-marketing surveillance (PMS) that would include at least 85% of patients in general practice. The patient base would meet more adequately the statistical requirements for PMS, to which you refer in your Nov 4 (p 1078) editorial, and would cover risks far less frequent than the 1 in 2000 that commercial groups can at best offer. A national system would also be less costly to the pharmaceutical industry, and would more directly be, and clearly be seen to be, in the public interest, and, as you point out, likely to provide surplus
Fear of crime SIR,-Mr Watts (Jan 13, p 116) suggests that the Home Office report on fear of crime was "misleading" in recording the average chance of being mugged as 1-8% per annum in the UK. I was the only medical member of the working party that compiled the report and, as a psychiatrist, had a special interest in the psychological aspects. The risk estimates cited were the best available from Home Office statistics. As Watts suggests, there are various factors that may determine the chances of being assaulted, and there are several ways in which these might change if conditions were altered. However, this does not make the figure misleading. The working party emphasised that the quality of life of many people is greatly impaired by their fear of crime, so that, for instance, they might not go out to any event after dark. But it was also noted that the groups most apprehensive of street violence are not those mostly likely to be affected by it. This is one reason why the proportion of the population who are apprehensive of mugging is very considerably greater than the proportion who might experience such assault. The working party’s conclusion was that the encouragement of as many people as possible to use public space freely would be one of the most effective ways of reducing both actual mugging and people’s fear of it. This seems to be the opposite view to that of Watts who, I hope, is not suggesting that the working party "condoned" a risk of 1 % or indeed any other risk. The working party’s remit was to advise on how fear of crime might be reduced, which is what it did. British Journal of Psychiatry, Royal College of Psychiatrists, London SW1X 8PG, UK
HUGH FREEMAN
