Monday, March 29, 2010

Ineffective screening for breast cancer?

A new study published in the British Medical Journal has raised new questions about the effectiveness of large scale breast screening programmes.

The report in Times Live can be found here. The abstract of original paper in the BMJ here.

The Danish study reports that they were "unable to find an effect of the Danish screening programme on breast cancer mortality. The reductions in breast cancer mortality (they) observed in screening regions were similar or less than those in non-screened areas and in age groups too young to benefit from screening, and are more likely explained by changes in risk factors and improved treatment than by screening mammography."

Late last year the U.S. Preventive Services Task Force (USPSTF) revised the recommendations for screening mammograms in women between 40-50 years of age.

Methinks it's about time our breast oncologists did some serious and honest review of the situation, though I seriously doubt they will say anything other than to defend the need to do lots more screening.

Sunday, March 21, 2010

Climatology - Post-Normal Science

Some might wonder why discussions about climate change often sound as if it was more of a debate about religion than it were about science; and fret about how political the whole issue has become. All this has apparently been because Climate Science is typical of a 'new' kind of scientific process called post-normal science (PNS).

Actually post-normal science (PNS) is not that new. It was first proposed by a pair of academics, Silvio Funtowicz and Jerome Ravetz in 1992 to characterize that type of scientific process that dealt issues of some urgency and where facts are sparse and uncertain. It is in effect, a kind of problem solving approach to complex science related issues. Because of the unavailability of good accurate data, all kinds of data from non-traditional sources can be used in finding urgent resolution to the problem. much of which did not require validation or proof. Much of medical science can be of this sort, where significant uncertainty exists in the management of critical and urgent clinical problems.

The Wikipedia entry reads: "According to its advocates, "post-normal science" is simply an extension of situations routinely faced by experts such as surgeons or senior engineers on unusual projects, where the decisions being made are of great importance but where not all the factors are necessarily knowable. Although their work is based on science, such individuals must always cope with uncertainties, and their mistakes can be costly or lethal. Given the greater importance of climate systems and the fact that less is known about them, conventional methods of inquiry, based on determining all relevant information before proceeding, are too slow and uncertain to deal with an issue too complex to be fully understood and too important to wait for confirmatory results."

Because this form of scientific approach cuts short many of the processes required to generate accurate and detailed data, it is important that the process relies on an 'extended peer community' (EPC) to provide quality assurance for the proposed solutions. This EPC consists "not merely of persons with some form or other of institutional accreditation, but rather of all those with a desire to participate in the resolution of the issue."

Funtowicz and Ravetz further point out that "Statistical theory tends to undervalue another sort of error, ironically called Type III, when the whole artificial exercise has no relation to the real issue at stake. Type III errors are a characteristic pitfall when the ‘normal science’ approach is deployed in post-normal situations. Modelling exercises are particularly prone to this sort of error, as when the gap between the available data and a manageable model on the one hand, and the real policy situation on the other, cannot be bridged."

The PNS approach is without doubt effective and necessary. However it does have a tendency, because of its relative lack of traditional scientific rigour and objectivity, to drift into an approach that is resembles activism or advocacy. Without checks and balances, the solution soon becomes orthodoxy. That is why the 'extended peer community' is essential to keep this paradigm 'honest'

The science of climate change fits exactly into this form of a scientific approach, being complex, urgent and bereft of good accurate data and understanding. The problem with it has been that the protagonists in the story got carried away with their zeal and lost their objectivity. The solution became orthodoxy. They proclaimed the science settled, and excluded the EMS, branding them deniers and skeptics etc. In so doing, they became advocates and activists. Some might say priests of a new religious order.

He writes: "We can understand the root cause of Climategate as a case of scientists constrained to attempt to do normal science in a post-normal situation. But climate change had never been a really ‘normal’ science, because the policy implications were always present and strong, even overwhelming. Indeed, if we look at the definition of ‘post-normal science’, we see how well it fits: facts uncertain,values in dispute, stakes high, and decisions urgent. In needing to treat Planet Earth like a textbook exercise, the climate scientists were forced to break the rules of scientific etiquette and ethics, and to play scientific power-politics in a way that inevitably became corrupt. The combination of non-critical ‘normal science’ with anti-critical ‘evangelical science’ was lethal. As in other ‘gate’ scandals, one incident served to pull a thread on a tissue of protective plausibilities and concealments, and eventually led to an unravelling. What was in the e-mails could be largely explained in terms of embattled scientists fighting off malicious interference; but the materials ready and waiting on the blogosphere provided a background, and that is what converted a very minor scandal to a catastrophe."

An early post by Elizabeth Bury (before Climategate broke) on this issue is also a good read.

Friday, March 19, 2010

Impact of climate change in Singapore??

In 2007, Environment and Water Resources Minister Yaacob Ibrahim announced a 2 year research programme to "gauge the impact of global warming". Implicit in that announcement was that global warming was already a given. The study was merely to look at the impact of such a certainty.

Recently, Minister Yaacob announced some findings of that study by the NUS Tropical Marine Science Institute that "by 2100 the average daily temperature here could increase by between 2.7 and 4.4 degrees Celsius from the present average of 26.8 degrees Celsius. In the same time-frame, sea levels could rise by between 24 and 65 cm". This is quite a substantial effect.

No mention here that climatology has recently been hit by a roiling wave of scandals which have threatened the very credibility of climate science altogether. The term "climategate" has been applied. Even the credibility and authority of the much vaunted IPCC’s 2007 Fourth Assessment Report (AR4) has been called into question. A considerable amount of the raw data that had been generated by the University of East Anglia Climate Research Unit has been called into question, and review of the data has been directed by Britain's Met Officer. And since it now appears that this set of data has been the main data set that other agencies have used as the raw data for the predictions, conclusions previously thought to be unquestionable, must now be questioned.

It is unclear what assumptions have gone into the NUS Tropical Marine Science Institute's computations. These assumptions are important, as is the raw data used to model the bold predictions the TMS Institute made for Minister Yaacob. Since, the report is not available for public scrutiny, either on NEA's website, or at the Institute's website, we cannot at the moment form an independent opinion of the validity of those predictions, and must depend on Minister Yaacob's summary presentation of those findings.

Assumptions are critically important in any predictions of future outcomes. Hopefully, the TNS Institute and the NEA will release these study report soon, so that the methodology and assumptions that were used in estimating the impact of any climate change of Singapore's environment impacclimate change can be understood by the public.

Wednesday, March 17, 2010

Cord blood banking - should you, or shouldn't you?

There was some recent publicity (see here and here) about this issue, provoked by a comment made by Dr Irving Weissman on this issue. As the Director of the Institute of Stem Cell Biology and Regenerative Medicine at Stanford University, his comments are taken seriously. He was quoted as saying that parents were being fleeced by stem cell bankers, and likened them to fraudsters.

The International Society for Stem Cell Research (ISSCR) of which Dr Weissman is also head, was quick to point out that his comments referred to the sale of stem cell therapies rather than the banking of stem cells.

Nevertheless the issue of cord blood banking needs to be clarified.

Cord blood blanking promises to store cells from the cord blood of babies, with a hope that these cells can be used in the treatment of various diseases later on. The idea is that these cells have some potential to differentiate into various mature cells. However it is not usually pointed out that this potential is limited and that these cells cannot form organs or tissues, and cannot replicate adequately to populate an adult body.

It should also be recognized that cord blood cells are banked in two possible ways, as part of a public bank, where the cells can be used by anyone with the appropriate need, or as a private bank where only the donor uses the cells. This latter form of transplant is called an autologous transplant.

While the former has considerable merit, because kids with various diseases can potentially benefit by tapping into this bank, the latter autologous bank has very little to offer.

There are relatively few proven indications for autologous transplants using cord blood, as compared to the heterologous use of cord blood. Furthermore the chance that a child will be able to use his own stored cord blood is very small.

The American Academy of Paediatrics (AAP) produced a policy statement on this issue in 2007. Their position hasn't changed since then. In the document they say: "Because there are no scientific data at the present time to support autologous cord blood banking and given the difficulty of making an accurate estimate of the need for autologous transplantation and the ready availability of allogeneic transplantation, private storage of cord blood as “biological insurance” should be discouraged."

Singapore has a public cord blood bank, called simply the Singapore Cord Blood Bank. They are doing good work and should be supported.

There are two private cord blood banks, Stemcord and Cordlife.

Their claims are that the cord blood can be used to treat an extremely wide range of diseases. Read their claims for yourself : for Stemcord, and for Cordlife.

Read the above for yourself, and take into consideration the AAP's policy statement: "Cord blood donation should be discouraged when cord blood stored in a bank is to be directed for later personal or family use, because most conditions that might be helped by cord blood stem cells already exist in the infant’s cord blood (ie, premalignant changes in stem cells). Physicians should be aware of the unsubstantiated claims of private cord blood banks made to future parents that promise to insure infants or family members against serious illnesses in the future by use of the stem cells contained in cord blood. Although not standard of care, directed cord blood banking should be encouraged when there is knowledge of a full sibling in the family with a medical condition (malignant or genetic) that could potentially benefit from cord blood transplantation."

One wonders why the Ministry of Health and the Singapore Medical Council does not come down firmer on these unsubstantiated claims by private cord banks.

Tuesday, March 16, 2010

Unethical screening - a timely warning

Minister of Health's recent blog on the ethics of unnecessary screening is very much welcomed.

There has been too much alarmist report of late particularly related to cancer screenings, many of which are nit really borne out by evidence based logic. It is easy to fuel panic and guilt. We have commented on the mammogram issue before.

Once we could count on the government hospital to do the essential, and only the essentials. The necessary and the needful. But nowadays, the government hospitals have become 'restructured' and often compete with the private sector for business. Who do we go to for sound advice on what is really necessary? I would really like to see the HPB come up with a sound evidence-based advice for the patient consumer, instead of just telling what services are available.

Meanwhile, caveat emptor.

H1N1 and Big Pharma

Anyone still interested in the H1N1 shamdemic, and the role of Big Pharma should this expose from Der Spiegel. It is by far the most comprehensive chronicle of the events which enveloped us last year.

I just quote a couple of excerpts from the report below, but you should read the whole thing and form your own opinions.

"According to the regulations, phase 6 becomes effective when a new virus is spreading uncontrollably in several regions of the world. The regulations say nothing about the severity of the disease.

In fact, the vast majority of experts on epidemics automatically associate the term "pandemic" with truly aggressive viruses. On the WHO Web site, the answer to the question "What is a pandemic?" included mention of "an enormous number of deaths and cases of the disease" -- until May 4, 2009. That was when a CNN reporter pointed out the discrepancy between this description and the generally mild course of the swine flu. The language was promptly removed.

Apparently German infectious disease experts also misunderstood the official WHO definition of phase 6. An influenza epidemic, according to Germany's national pandemic plan -- updated in 2007 -- is "a long-lasting, international situation involving substantial loss…and causing such lasting damage as to jeopardize or destroy the livelihood of large numbers of people."

The situation on June 11, 2009 did not correspond with these descriptions. Critics were already asking derisively whether the WHO had any plans to declare the latest outbreak of the common cold a pandemic. "Sometimes some of us think that WHO stands for World Hysteria Organization," says Richard Schabas, the former chief medical officer for Canada's Ontario Province.

""The pharmaceutical industry did not influence any of our decisions," says Fukuda. But in mid-May, about three weeks before the swine flu was declared a pandemic, 30 senior representatives of pharmaceutical companies met with WHO Director-General Chan and United Nations Secretary General Ban Ki Moon at WHO headquarters. The official reason for the meeting was to discuss ways to ensure that developing countries would be provided with pandemic vaccine. But at this point in time the vaccine industry was mainly interested in one question: the decision to declare phase 6.

Everything hung on this decision. At stake was nothing less than a move to supply large segments of the world's population with flu vaccine. Phase 6 acted as a switch that would allow bells on the industry's cash registers to ring, risk-free. That's because many pandemic vaccine contracts had already been signed. Germany, for example, signed an agreement with the British firm GlaxoSmithKline (GSK) in 2007 to buy its pandemic vaccine -- as soon as phase 6 was declared. This agreement could explain why Professor Roy Anderson, one key scientific advisor to the British government, declared the swine flu a pandemic on May 1. What he neglected to say was that GSK was paying him an annual salary of more than €130,000 ($177,000).

"What was this pandemic? Was it all just "good practice for an emergency," as WHO advisor and industry lobbyist Osterhaus puts it? Did the authorities do everything right, as Australian epidemiologist John Mackenzie insists?

Certainly not. No one at the WHO, RKI or PEI should feel proud of themselves. These organizations have gambled away precious confidence. When the next pandemic arrives, who will believe their assessments?"