Clinical Trials on Diet
There has been talk recently of benefits, or otherwise, of having mammograms.
Many people are still looking for accurate information, so this paper might add to confusion, or perhaps clear up some questions. Good luck!
At the recent ESMO Conference (European Society for Medical Oncology), Karsten Jørgensen, of the Nordic Cochrane Center in Copenhagen, talked about the perils derived by over-diagnosis with mammography screening.
Jorgensen opened his talk with a provokative quotation taken by the paper of JA Muir Gray and June Austoker, namely: “All screening programmes do harm; some also do good. The responsibility of the policy-maker is to decide which programmes do more good than harm at reasonable cost and then introduce them, once they are confident that the screening programme could and will reach the standard of quality required for success.
The ratio of benefit to harm is not, however, constant and this relationship demonstrates a shifting balance”1, and posed another similarly provokative question to the audience, namely whether mammography screening for breast cancer can be actually numbered among the programmes that also do good.
To start out, Jorgensen gave some examples of cases where over-diagnosis led to abandonment of the screening programmes: lung cancer with chest x-ray was abandoned as a screeening programme when 29-50 % more cases were found in the screened group. The same happened with prostate cancer screening with PSA (20-70 % extra cases in screened group) and screening for neuroblastoma in children with urine test: 100 % over-diagnosis in two independent trials. Not to talk about the final screening test: autopsy, where practically every single one of us is found to have thyroid lesions!
Two fundamental concepts need to be spelled out and properly defined for every screening programme that we undertake:
1) Over-diagnosis, defined as the phenomenon for which, if screening were detecting breast cancer that would otherwise not have been diagnosed, it would be expected that in controlled trials there would be a persistent excess number of breast cancers in the screened group compared with the control group (the definition is taken from the 1986 Forrest Report, which formed the basis for the breast cancer screening programme in the UK, and that can be read here.
2) Over-treatment: an obvious source of harm associated with any screening programme is unnecessary treatment of cancers that were not going to cause death or symptoms (from the 2003 IARC Handbooks of Cancer Prevention, Volume 7: Breast Cancer Screening, the electronic version can be found here.
As stressed by Jørgensen, “It’s not over-diagnosis the problem we need to tackle in breast cancer treatments, it is overtreatment! Think how you would explain to a woman that the surgery, radiotherapy or chemotherapy she underwent, together with all the worries and preoccupation that she and her family went through, were unnecessary? That is the real problem!”
The Nordic Cochrane Center (NCC), where Jorgensen works, is an independent research and information centre that is part of the Cochrane Collaboration (an international network of individuals and institutions committed to preparing and disseminating systematic reviews of the effects of health care). A review about breast cancer screening with mammography was compiled in 2009, and is available upon download here on their website. In this review, eight eligible trials were identified, and 600,000 women were included in the analyses. Three trials with adequate randomisation did not show a significant reduction in breast cancer mortality at 13 years (relative risk (RR) 0.90); four trials with suboptimal randomisation showed a significant reduction in breast cancer mortality with an RR of 0.75. Numbers of lumpectomies and mastectomies were significantly larger in the screened groups (RR 1.31, 95% CI 1.22 to 1.42) for the two adequately randomised trials that measured this outcome; the use of radiotherapy was similarly increased. The authors of the review, Peter Gotzsche and Margrethe Nielsen2, conclude that, although screening is likely to reduce breast cancer mortality, with a reasonable estimate of 15% reduction (corresponding to an absolute risk reduction of 0.05%), it also led to 30% over-diagnosis and overtreatment, or an absolute risk increase of 0.5%.
To put the results in other figures, this means that for every 2000 women invited for screening throughout ten years, one will have her life prolonged and ten healthy women, who would not have been diagnosed if there had not been screening, will be treated unnecessarily! Furthermore, more than two hundred women will go through psychological distress due to false positive results. Gotzsche and Nielsen conclude that it is thus not clear whether screening does more good than harm. Jørgensen agrees with them and, as he started out his talk with a provocative question, he concluded it with another thought-provoking message. He showed an old print campaign advertisement by the American Cancer Society, which reads: “If you haven’t had a mammogram, you need more than your breasts examined”, conveying therefore the message that women would be stupid if they did not undergo mammography screening. But, given current data, such a message needs to be seriously re-evaluated.
Once you have had cancer, or if you are concerned, over-50, etc. it is a good idea to do the simple Bowel Cancer screening test at home. However, if you then need to get a Colonoscopy, and if you had polio as a child, or some other neurological or muscular conditions, ask about anaesthesia. When I phoned Charing Cross Hospital about this, the Nurse in charge pooh-poohed the suggestion, even when I told her about eminent hospitals abroad that have this as part of the procedure for anyone who had polio. Her words were “we treat everyone the same”. In other words, if you have a condition that it going to make it painful – tough.
She then said , “WE may decide not to give a sedative”. No suggestion of consulting the patient as to what they want.
I wrote to Charing Cross to ask why this nurse wouldn’t even look up information- and so far no reply – two months later. This barbaric type of care just has to be stamped out. At least the nurse should have acknowledged she didn’t know anything about polio, but would go off and find out about it.
1. Gray JA and Austoker J (1998) Quality assurance in screening programmes Br Med Bull. 54(4) 983-92
2. Jørgensen KJ and Gøtzsche PC (2009) Overdiagnosis in publicly organised mammography screening programmes: systematic review of incidence trends BMJ 339:b2587.
Boer R, Warmerdam P, de Koning H, et al (1994) Extra incidence caused by mammographic screening Lancet 343(8903) 979.
Esserman L and Thompson I (2010) Solving the overdiagnosis dilemma J Natl Cancer Inst 102(9):582-3
Veronesi A and Serraino D (2009) Screening: is breast cancer overdiagnosed? Nat Rev Clin Oncol. 6(12):682-3
Welch HG and Black WC (2010) Overdiagnosis in cancer J Natl Cancer Inst 102(9):605-13
Anyone who fumes at medics who think cancer affects our brain cells, or has been told, “you are ONLY a patient”, will enjoy filling in a new survey.
Eurocancercoms has launched a survey in five european languages, to uncover the types of information We want: people with cancer, their family and friends.
The survey is targeting cancer patient and their families to get their opinions on the current state of information available and how it could be improved. The eurocancercoms project will go on to analyse the research, and develop strategies to make the best cancer information accessible to patients and the public. Results of the survey will be hosted online.
If you would like to take part please click on the appropriate link below.
To complete the survey in English click on the link below.
Pour participer à l’enquête en français cliquez ici
Zur Umfrage in Deutsch bitte hier klicken
Per completare l’indagine in italiano fare clic qui
Para completar la encuesta en español dé clic aquí
Can’t wait for results – only fault I have found with survey is that we will keep on having to watch the Eurocancercoms website for results (but perhaps that’s why they aren’t emailing results to us!)
This is an exciting new project looking at the issues surrounding communication and dissemination of cancer information across Europe.
The project is divided in to six areas, involving the whole cancer community from scientist to patient.
One thing that comes over very strongly is that this is an official project that is going to involve us PATIENTS.
The organisers have kindly given permission for me to post extracts, so that readers can get a taste of what is happening in the Eurocommunity. As the project develops, I will be posting extracts, or for the full flavour go to their website – I can promise you they have taken on board our distaste of NHS-speak, and it is written in English English!
There are some very interesting video discussions, and it is shaming how well Danes, Dutch etc. speak our language – a lesson to some of our medics who try to blind us with NHS-speak!
To find out more, go to the companion story under eurocancercoms, then click on to their website: www.eurocancercoms.eu.