Rapid Responses to:
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Rapid Responses: Rapid Responses published:
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Inappropriate use of evidence?
- Hazel Thornton (24 August 2002)
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Screening and Mastectomy rates
- Michael Baum (25 August 2002)
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Misleading paper on mastectomy rates in a screening programme
- Peter C Gøtzsche (27 August 2002)
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Confounding Factor
- Des Spence (27 August 2002)
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Are breast cancer screenig programmes increasing rates of mastectomy?
- Robert Hall (29 August 2002)
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Study internally invalid
- Richard H Moore (1 September 2002)
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Re: Botticelli's "birth of Venus"
- Eugenio Paci, Stephen W. Duffy (24 October 2002)
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Incomplete data and wrong conclusion: what happened to 70% of women diagnosed in 1996?
- Jayant S Vaidya (16 July 2005)
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Re: Incomplete data and wrong conclusion: what happened to 70% of women diagnosed in 1996?
- Jayant S Vaidya (28 January 2006)
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Hazel Thornton, Honorary Visiting Fellow, Department of Epidemiology and Public Health, University of Leicester. "Saionara", 31 Regent Street, Rowhedge, Colchester, CO5 7EA
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The NHS Breast Screening Programme screened 1,409,790 women aged mainly between 50-65 years in 1999/2000. [1] 9,525 cancers were detected of which 2,009 (ca. 21%) were ductal carcinoma in situ (DCIS). This represents overall 6.39 cancers detected per 1,000 women screened. The `Florence` observational study [2] studied a total of 59,947 women aged 50-69 in the seven years from 1990-1996. Total numbers of cancers detected, or of DCIS were not provided in the researchers` report, but at a rate of, say, ca. 2 per thousand early stage cancer and, say, 0.75 per thousand late stage cancers (T2+) shown in their graph, we could estimate, say 200 cancers at most were detected. Bearing in mind the biases introduced by an average attendance in Florence of only 60% of those invited, compared with 75.4% in the U.K.; the cultural differences; and the difference in quality of evidence obtained from a small number of participants in an observational study compared with evidence from a large systematic review executed in accordance within a rigorously designed Cochrane protocol [3] cited by the authors, suggests to me that it is unwise to jump to the conclusions shown in the media coverage in the UK today relating to the NHS Breast Screening Programme. No mention was made of the psychological consequences to women diagnosed through screening, receiving treatment by mastectomy or by lumpectomy with or with radiation, (particularly for borderline cases), or of other considerable psychological outcomes for which the researchers in the Danish Review provided data, references and comment. In the media coverage in the U.K. on day of publication, the conclusion drawn by Paci et al that "the rate of breast conserving surgery has increased significantly with the advent of screening, and the rate of radical surgery has declined significantly" was presented with scarcely a mention of the disparities in the weight, or place, of the findings. The hasty endorsements in the media by public figures implying a refutation of the UK findings that mammographic screening leads to over-diagnosis and over-treatment is to be deplored, when the data from the UK indicate otherwise. Those who selectively present inadequate evidence to support a belief will ultimately lose the trust of the public at large in the face of mounting evidence that mammographic screening is not as effective as had been predicted at reducing mortality from breast cancer; is certainly not cost-effective; has numerous adverse effects for many women invited who are not accurately diagnosed; and leads to mutilating treatment, particularly of the 1 out of 5 borderline cases diagnosed through the programme, three-quarters of whom will never progress to invasive cancer. Those women would certainly agree that that surely is over-treatment? (1,500 in the U.K. in 1999/2000 alone.) Hazel Thornton. Independent advocate for quality in research and healthcare. References: [1] NHS Breast Screening Programme Annual Review 2001. [2] Eugenio Paci, Stephen W. Duffy, Daniela Georgi, Marco Zappa, Emanuele Crocetti, et al. Are breast cancer screening programmes increasing rates of mastectomy? Observational study. BMJ 2002; 325:418 [3] Olsen O. Goetzsche PC. Cochrane Review on screening for breast cancer with mammography. Lancet 2001; 358: 1340-1342 |
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Michael Baum, Emeritus Prof. of Surgery University College London The Portland Hospital, 212-214 Great Portland Street, London W1W 5QN
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Letter to BMJ August 2002 Editor, Re: Are breast screening programmes increasing rates of mastectomy? There are two welcome side effects of population screening programmes for breast cancer. Firstly an increasing awareness of the disease which encourages symptomatic women to present with smaller tumours and secondly the establishment of specialist clinics set up to cope with the flow of worried women resulting from the trawl of the asymptomatic population. Specialist clinics are more likely to offer breast-conserving techniques. It is therefore a great over-simplification for Paci on his colleagues to assume that mammographic screening per se is responsible for the fall in mastectomy rates in Florence ( BMJ 24th August 2002). Furthermore it is an over-interpretation of the data to extrapolate the findings from one city in Italy to National population based programmes such as the NHSBSP. In Florence the mastectomy rate is 33% for screen-detected cancer, which compares well with our national statistics for 2000-2001 of 32% for DCIS and 29% for invasive cancer.[1] However in the UK there is an enormous range with for example 42% of women in Wales experiencing mastectomy for DCIS (“ early breast cancer”!) and 38% of women in the Principality treated by mastectomy for screen detected invasive disease. I have been unable to trace the trends in mastectomy rates in the UK since screening was introduced in 1988 but a natural experiment would be to consider the rates in women under and over 50 years of age. If the trends were the same then this could not be attributed to screening as the under 50s are not on the invitation list. One final point, I notice that the absolute rate for breast cancer surgery in Florence has risen from 2.26 to 2.49 per 1000 women a year between 1990 and 1996, which is a 10% rise. I wonder if this could be attributed to the over diagnosis of Duct Carcinoma in Situ (DCIS). DCIS accounts for about 20% of “cancers” detected at screening [1] and it has been estimated that at least half of these would fail to progress to an invasive phenotype if left undiscovered [2]. The Uffizi Gallery in Florence is home to Botticelli’s “ birth of Venus”. In this popular icon we see Aphrodite rising from a seashell demurely covering her left breast with her hand. I always thought this was modesty but maybe she’s hiding the scar of an unnecessary operation for screen detected DCIS? Yours Sincerely, Michael Baum References: [1] NHS Breast Screening Programme and British Association of Surgical Oncology Breast Group; An Audit of screen detected breast cancers for the year of screening April 1999 to March 2000. Produced by the West Midlands NHS and Cervical screening quality assurance reference centre: Published by the NHS Breast Screening Programme April 2001 [2] Neilsen M, Thomsen JL, Primdahl S et al: Breast cancer and atypia among young and middle aged- women : A study of 110 medico-legal autopsies. British J Cancer 1987;56:814-819 |
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Peter C Gøtzsche, Director Nordic Cochrane Centre, Rigshospitalet, DK-2100 Copenhagen Ø, Denmark
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The observational study by Eugenio Paci and colleagues builds on a false assumption. The authors assert that if screening increases the number of mastectomies, populations in which screening has been introduced should see a subsequent increase (1). This is not correct. Since the mastectomy rate has gone down steadily throughout many years, also in countries without screening, it is only to be expected that Eugenio Paci and colleagues also find a decrease in the mastectomy rate in the period 1990-1996 in Florence, when screening was introduced. The relevant question is whether the decline in the mastectomy rate is slower when women are invited to participate in screening programmes, compared to when they are not invited. We found evidence from the randomised trials of screening that this is the case (2). Furthermore, the authors’ findings from Florence are contradicted by a far larger study from the Southeast Netherlands, where screening was introduced in the same time period. I calculated that the number of invasive cases increased by 78%, the numbers of women who underwent breast-conserving surgery increased by 71%, and numbers of women who underwent mastectomy increased by 84% (3). What is more, these authors did not include carcinoma in situ which is rarely detected without screening but is frequently treated by mastectomy (BASO Breast Audit 1999/2000, available from http://www.cancerscreening.nhs.uk/breastscreen/publications.html) There is much misinformation about screening. I therefore recommend women who want to get a fair and balanced account of this issue to consult an evidence-based consumer organisation, for example the National Breast Cancer Coalition in USA (http://www.stopbreastcancer.org/bin/index.htm, Positions, Facts and Analyses). At present, breast cancer screening is not possible without overdiagnosis and overtreatment. This also applies to mastectomies, and it should be remembered that breast conserving surgery with radiotherapy is a pretty rough treatment as well that can lead to decreased survival (4). Competing interests: None. 1. Paci E, Duffy SW, Giorgi D, Zappa M, Crocetti E, Vezzosi V, et al. Are breast cancer screening programmes increasing rates of mastectomy? Observational study. BMJ 2002; 325: 418. 2. Olsen O, Gøtzsche PC. Systematic review of screening for breast cancer with mammography (http://image.thelancet.com/lancet/extra/fullreport.pdf). 3. Gøtzsche PC. Trends in breast-conserving surgery in the Southeast Netherlands: comments on article by Ernst and colleagues. Eur J Cancer 2002;38:1288. 4. Early Breast Cancer Trialists' Collaborative Group. Favourable and unfavourable effects on long-term survival of radiotherapy for early breast cancer: An overview of the randomised trials. Lancet 2000;355:1757- 70. |
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Des Spence, General Practioner Glasgow G20 9DR
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Language is very important and I am concerned buy the use of language in many medical articles as I feel these are an attempt to confuse and intimidate the reader. In this article the data is presented in a potential flawed manner and misses a very basic issue and confounding factor There is observed fall in the number of mastectomies from 1990 after the advent of breast screening and it is strongly suggested that trend is related to breast screening programme. We are not shown, however, the trend in mastectomy surgery prior to 1990 and whether a downward trend had preceded screening mammography. It should be noted that from the mid 1980s it was recognised that lumpectomy was as effective as mastectomy1 and this change in surgical practice might explain the observed reduction in mastectomy rates rather than breast screening. There is a huge industry around breast screening and people want to believe it works. We should recognise the harm of health care interventions and believing is not enough. 1.Review confirms lumpectomy as safe as mastectomy Fiona Godlee BMJ 1995; 311: 1451-1452. Competing Interest "Pledge at nofreelunch.org" |
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Robert Hall, hon reasearch fellow York district hospital
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Sir- The division of operation by Paci and colleagues( BMJ 2002;325:418) between radical mastectomy and breast conserving operation seems to equate radical mastectomy (=total mastectomy + axillary clearance) with simple mastectomy ( without axillary clearance) in their argument that breast screening in Florence results in more frequent breast conservation and less frequent mastectomy. Maybe there was never need in Florence between 1990 and 1996 to remove the whole breast without axillary clearance? It also almost looks from their figure that in 1991, 1992, and 1995 there were more operations than there were cases of cancer. Whilst their figure might well show that between 1990 and 1996 the proportion of early breast cancer cases treated by breast conserving operations did not change, and that the proportion of women with tumours =/> 2 cm pathological diameter treated by axillary clearance as well as total mastectomy diminished, these trends might well result from features not directly related to tumour size caused by the introduction of screening, such as the undoubted changes of fashion for breast cancer treatment during the last twenty years. Their inclusion of data from the years before 1990 ( breast screening introduced in Florence) might have thrown light as to how likely the apparent reduction in radical mastectomy in favour of breast conservation might not have arisen from confounding variables. Yours, Robert Hall
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Richard H Moore, Fellow in Breast Surgery, University of Hull Castle Hill Hospital, Cottingham, HU16 5JQ
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Sir, With reference to the article ‘Are breast cancer screening programmes increasing rates of mastectomy ? Observational study’, Paci, E et al, BMJ 325, 24th August 2002, 418 Although there is value in raising the issue, that breast conservation surgery and mastectomy rates may change primarily as a result of the introduction of screening, the conclusions as presented are internally invalid and are not credible in the light of the evidence presented. There are many confounding and unaccounted for variables which could be contributing to the observed reduction in this population’s absolute mastectomy rates which deserve identifiaction and discussion. Screening Biasing Results:- The advent of screening could bias the results towards breast conserving surgery; no mention is made as to whether the lumpectomies as described were purely therapeutic or contained diagnostic breast biopsies as a result of screening. Thus, the meaning of the terms “breast conserving surgery” and “lumpectomy” requires clarification in this context. Hidden within these results of an increase in ‘breast conserving surgery’ could well be what could have turned out to be unnecessary biopsies for falsely positive mammograms, and it would be dangerous to assume that all “lumpectomies’ were performed for a therapeutic intent only. This figure, without such clarification, is potentially biased and therefore internally invalid. It contains a potential bias in favour of screening increasing the local excision rate and relatively decreasing the mastectomy rate which in reality could be hiding an increased rate of biopsies for false positive disease. Therefore a more meaningful figure would be the observed rates of better defined surgical categories in the screened versus the non screened population. As such it can not be assumed that there was a purely therapeutic intent in these patients, and the reported mastectomy rate is purely an quantitative observation from which no qualitative inference as to the reasons underlying it can be made. Neither is mention made made of the quantitative contribution of the screened and non screened populations towards the mastectomy rates, with an absolute mastectomy rate only being presented. The same problem applies to the breast conservation surgery rate. If only 60% of invited women take up the offer of screening, presumably the increase in breast conservation surgery is attributed to this group, however, the analysis in the paper refers to the population of women invited as a whole rather that those who accepted the screening offer. Herein lies an unquantifiable bias. Other Counfounding Factors: Working Practices:- No mention is made of whether changes in local working practices have influenced the mastectomy rates. Although it is appreciated that most of the results date from 1990-1996, whether neoadjuvant chemotherapy or primary hormonal therapy has been used in this population has not been commented on. It is exactly treatment biases such as these which can influence mastectomy rates. DCIS:- It is also naive to include DCIS with early breast cancer. In the paper Stage 0 Breast Cancer, DCIS, is classified with early stage invasive breast cancer.As the two are biologically different entities with potentially different biological activities, prognosis and treatment, this will introduce an unpredictable bias into the interpretation of observed mastectomy rates. It almost leads to the assumption that DCIS invariably leads to invasive disease. Observational Study:- Being an observational study, there is no control group to make a valid comparision, either temporally with historical controls or any attempt to observe concomitant mastectomy rates in screened versus non screened populations. Unfortunately this is essentially a retrospective study and as such one can not expect the study design to have been as appropriate as if it had been perormed as a prospective study. However I do not feel that there is enough internal or external validity within this paper to reach the conclusions stated by the authors. |
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Eugenio Paci, Epidemiologist CSPO Via di San Salvi 12 Florence 50125, Stephen W. Duffy
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In response to some comments it is worth pointing out that: • Gøtzsche and others have claimed that the introduction of mammographic screening increases mastectomy rates. • We have showed that this was not the case in Florence However, Professor Baum’s irony about scars in the breasts of Florentine women is at best provocative and aggressive. In table 1 we present data of rounds 1 to 4 of the Florence screening programme which started in 1990. It is a matter of regret to us that some women attending for screening undergo surgical biopsy for a condition which ultimately proves benign, but in total the number of women with a negative excision biopsy was 190 in 10 years of duration of the breast screening programme, with around 130,000 screens. Whatever your opinion might be about aggressiveness of in situ carcinoma ( the issue of overdiagnosis will be discussed in a forthcoming paper), the number is far from epidemic. Women with a breast scar are in the large majority breast cancer patients. In turn, the vast majority of these are invasive cancer patients. We suggest that is better to maintain the Botticelli's birth of Venus as a symbol of the beauty of Florentine women. Eugenio Paci Stephen W. Duffy
Table 1
Service screening data from the Florence Breast Cancer Screening programme
Round Women screened No of No of No of No of
population referrals excision screen screen
(50-69) for biopsies detected detected
assessment invasive carcinoma
cases in situ
1 28295 1284 278 211 21
2 33973 1420 224 158 30
3 35829 1397 215 167 12
4 35869 1458 222 133 17
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Jayant S Vaidya, Senior Lecturer and Consultant Surgeon Department of Surgery and Molecular Oncology, Ninewells Hospital and Medical School, Dundee DD1 9SY
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I have a major concern with this paper by Paci and colleagues. As per the figure (Paci et al, BMJ 2002;325:418) the total (early stage + late stage) incidence of breast cancer increased from about 2.7 (1.3+1.4)per 1000 in 1990 to 4.1 (2+2.1) per thousand in 1996. So, if all the data was captured, I cannot understand what happened to more than 70% of women being diagnosed with breast cancer in 1996. In 1990 there were 2.7 /1000 diagnoses and 2.2/1000 operations. In 1996, there were 4.1 /1000 diagnoses but only 1.2 /1000 operations!? What happened to the other 2.9 /1000 patients diagnosed with breast cancer? What operations/treatments did they have? Clearly a large amount of data about these patients' operations is missing. No conclusion about operation rates can drawn from the data presented. Competing interests: None declared |
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Jayant S Vaidya, Senior Lecturer/ Consultant Surgeon DD19SY
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I have realised that I looked at the wrong lines in the graph while doing the above calculations- so my conclusions and comments are very embarrassingly completely unfounded. I wish to withdraw the above rapid response. Competing interests: I am the author of the earlier response and wish to delete that response |
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