Rapid Responses to:
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Rapid Responses: Rapid Responses published:
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We need new Ways in preventive Medicine
- Stagnaro Sergio (5 October 2002)
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Screening populations at low risk carries high risks
- Luc Bonneux (9 October 2002)
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Prostate cancer screening and treatment
- Simon Brewster, Mark Feneley and Roger Kirby (17 October 2002)
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Digital rectal examination of the prostate
- W. John Lockley (7 August 2004)
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Stagnaro Sergio, Specialist in Blood, Gastrointestinal, and Metabolic Diseases. Researcher in Biophysical Semeiotics. Via Erasmo Piaggio N° 23/8. 16037 Riva Trigoso (Genoa) Italy.
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Sirs, I agree with the statement that “The lack of association between more intensive screening and treatment and lower prostate cancer mortality suggests that trials should continue in order to settle this question”. In my opinion, from such a view-point, we have to try new and more efficacious screening types for malignancies, easy to perform on very large scale and reliable in ascertain the “real” initial stage in individuals involved by oncological terrain, of course. A 45-year-long clinical experience, in fact, allows me to state that nowadays a new bed-side preventive medicine can be applied by all general practitioners around the world in an efficient and practical manner. (See my site HONCode ID. N. 233736 http://digilander.libero.it/semeioticabiofisica, Biophysical-Semeiotic Constitutions, as well as Bibliography, and the weekly Page, I hold in the italian site www.katamed.it, article N° 12: Oncological Terrain). As a matter of fact, physician nowadays can recognize clinically individuals at "real" risk of malignancies, both solid and liquid, including their precise location, arteriosclerosis, diabete mellitus, both type 2 (1) and 1, arterial hypertension, rheumatic disorders, dyslipidemia, a.s.o. 1) Stagnaro S., Diet and Risk of Type 2 Diabetes. N Engl J Med. 2002 Jan 24;346(4):297-298. letter [PubMed –indexed for MEDLINE]. |
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Luc Bonneux, Associate Professor Julius Center for Health Sciences, UMC, HP D 01.335, PB 85500, 3508 GA Utrecht, the Netherlands
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Dear editor, In their key points, the authors suggest that “The lack of association between more intensive screening and treatment and lower prostate cancer mortality suggests that trials should continue in order to settle this question.” More research is the classical conclusion of all studies, but is it true? First, you can’t use trials to prove that something doesn’t work. That is unethical: there has to be at least a sound presumption that screening will be effective.(1) It is also futile, as newer screening tests will replace the older ones. The clamour for more testing will only increase. Second, even if screening would be effective, could it ever be efficient? The risk of any specific cancer is so low, that the back of an envelope is sufficient. The absolute risk of death from prostate cancer before the age of 75 was 1.33% in the Netherlands.(2) Assume a risk reduction of 25% (which would be high): the absolute risk reduction is 0.33%, or 300 men need to participate in a population screening programme to save one death. If we take 5 screening rounds in the programme to obtain this reduction (which would be a small number), at 1500 occasions participants will be at risk of overdiagnosis and overtreatment, known to cause impotence and incontinence, to save one death. Cancer screening is based on biased information: benefit is taken for granted, the risks and perils of screening are not mentioned. The simple calculation I showed can easily be made for all screening procedures: numbers of screening procedures, numbers of diagnostic and therapeutic interventions induced and numbers of disabilities caused by screening compared to numbers of lifes saved. Many people will not believe you, which shows that they did understand you all too well. Part of informed consent is that people should be informed of the true, absolute risks, including risks of overdiagnosis and overtreatment. Cancer risk management should learn from cardiovascular risk management,(3) where the risks are many times higher but only populations at increased risk are targeted. 1. Adami HO, Baron JA, Rothman KJ. Ethics of a prostate cancer screening trial. Lancet 1994;343(8903):958-60. 2. Netherlands Cancer Registry. Incidence of cancer in the Netherlands 1997. Netherlands Cancer Registry, 2001. 3. Jackson R, Barham P, Bills J, Birch T, McLennan L, MacMahon S, et al. Management of raised blood pressure in New Zealand: a discussion document. BMJ 1993;307(6896):107-10. |
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Simon Brewster, Consultant Urologist Churchill Hospital, Oxford, OX3 7LJ, Mark Feneley and Roger Kirby
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Editor – The suppositions that Lu-Yao et al required to justify the conclusions from their data raise concern, not least because these comprise 85% of the discussion1. Their “natural experiment” is a retrospective comparison of mortality in Seattle and Connecticut where prostate cancer screening practice has differed. The findings cannot confirm that screening has no impact on mortality, because this question cannot be adequately addressed by a study of this design. Similar criticism also applies to the perceived benefit of population screening in Tyrol, Austria where intervention was not prospectively randomised2. The lack of survival benefit does not exclude health benefit that may be associated with reduced prevalence of metastatic prostate cancer, as observed in Tyrol over the five-year screening period and following treatment with radical prostatectomy in Sweden3. The “natural experiment” of Lu-Yao et al describes study populations aged 65-79 years in which the majority of the men were over 70 years at diagnosis. There are several reasons at the outset to suppose that outcomes in this group would not be representative of screening, not least owing to greater age at diagnosis, the adverse prognostic bias this may impose and the potential for BPH to impact on cancer detection. If there were to be any benefit from screening in the study age group, this would certainly be diluted significantly by competing causes of death. It would appear however that Oxford University’s Department of Primary Health Care has prejudged the issues of prostate cancer screening and treatment. Funded by the National Screening Committee, which on one hand supports informed PSA testing but only in men already aware of the test and on the other does not support dissemination of this information to the public, this group have focussed on the “misunderstandings” and lack of awareness of several purposively sampled prostate cancer patients who kindly gave them an interview4. They previously asserted that urologists do not discuss watchful waiting with patients who might have chosen this option, again based on patients recall of consultations5, yet not once do they discuss the significant morbidity and mortality figures associated with advanced prostate cancer that commonly confronts urologists, oncologists, palliative physicians, GPs and patients themselves. Robust answers require definitive well-planned studies. Findings from ongoing high-quality randomised studies of screening (such as the ERSPC and ProTect), treatment (PLO) and prevention (PIVOT) are eagerly awaited. In addition, further significant investment in basic research is required to improve the care of our patients. Simon Brewster, Consultant Urologist
Mark Feneley, Consultant Urologist
Roger Kirby, Professor of Urology,
1 Lu-Yao G, Albertsen PC, Stanford JL, Stukel TA, Walker-Corkery ES, Barry MJ. Natural experiment examining impact of aggressive screening and treatment on prostate cancer mortality in two fixed cohorts from Seattle area and Connecticut. BMJ 2002; 325:740-743. 2 Bartsch G, Horninger W, Klocker H, Reissigl A, Oberainger W, Schonitzer D et al. Prostate cancer mortality after introduction of prostate-specific antigen mass screening in the federal state of Tyrol, Austria. Urology 2001; 58: 417-424. 3 Holmberg L, Bill-Axelson A, Helgesen F, Salo JO, Folmerz P, Haggman M et al. A randomised trial comparing radical prostatectomy with watchful waiting in early prostate cancer. New Eng J Med 2002; 347: 781-789. 4 Chapple A, Ziebland S, Shepperd S, Miller R, Herheimer A, McPherson A. Why men with prostate cancer want wider access to prostate-specific antigen testing: qualitative study. BMJ 2002; 325: 737-9. 5. Chapple A, Ziebland S, Herheimer A, McPherson A, Miller R, Shepperd S. Is “watchful waiting” a real choice for men with prostate cancer? BJU International 2002; 90: 257-264. |
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W. John Lockley, GP The Oliver Street Surgery, Ampthill, Bedfordshire MK45 2SB
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It is always difficult to overturn established orthodoxies: often we practise medicine in a particular way without thinking about why we do it, simply because ‘that’s the way we were taught’. Despite having practised medicine for more than a quarter of a century I have always found digital rectal examination of the prostate to be very difficult, to the point of unreliability. With the patient in the left lateral position the prostate lies in the most awkward position to reach, either to be felt with the back or side of the index finger, or else with the pulp of the finger, but only after twisting the hand round awkwardly or by half-kneeling on the floor. Even when doing this, I have never felt confident in the results of my digital rectal examination. A moment’s thought suggests that placing the patient the opposite way round, in the right lateral position, facing the practitioner, with the knees drawn up, means that when the examining finger is inserted, the sensitive pulp lies directly over the prostate. Having tried this method for about six months, I can report that the difference is amazing: it is extremely easy to feel the prostate in detail in this manner, and my degree of confidence in the results of my examinations has risen hugely. I now use this method routinely. It may be argued that in the right lateral position it is now not so easy to examine the posterior wall of the anus and rectum, but this is no worse than having to examine the prostate in the left lateral position, and the prostate has always to be felt, whereas there is much less frequent need to examine the posterior wall in such detail. In any case, if there is any remaining uncertainty the patient can always be placed in the orthodox left lateral position and the examination repeated. May I commend this method to your readers? Dr John Lockley GP The Oliver Street Surgery, Ampthill, Bedfordshire MK45 2SB JohnLockley@compuserve.com Competing interests: None declared |
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