Harms from breast cancer screening outweigh benefits if death caused by treatment is included

Contact: Emma Dickinson edickinson@bmjgroup.com 44-020-738-36529 BMJ-British Medical Journal

Cancer expert remains to be convinced by breast screening review

Harms from breast cancer screening outweigh benefits if death caused by treatment is included

Michael Baum, Professor emeritus of surgery at University College London says that, while deaths from breast cancer may be avoided, any benefit will be more than outweighed by deaths due to the long term adverse effects of treatment.

He estimates that, for every 10, 000 women invited for screening, three to four breast cancer deaths are avoided at the cost of 2.72 to 9.25 deaths from the long term toxicity of radiotherapy.

These figures contrast with an independent report on breast cancer screening, led by Sir Michael Marmot and published in November last year. Marmot and his committee were charged with asking whether the screening programme should continue, and if so, what women should be told about the risks of overdiagnosis.

They concluded that screening should continue because it prevented 43 deaths from breast cancer for every 10,000 women invited for screening.

The downside was an estimated 19% rate of overdiagnosis: 129 of the 681 cancers detected in those 10,000 women would have done them no harm during their lifetime. However, those women would have undergone unnecessary treatment, including surgery, radiotherapy and chemotherapy.

But despite this higher than previous estimate of overdiagnosis, they concluded that the breast screening programme should continue.

The report also judged that screening reduces the risk of dying from breast cancer by 20%. But Professor Baum disputes these figures, saying the analysis takes no account of improvements in treatment since these trials were done, which will reduce the benefits of screening. Nor does it make use of more recent observational data.

With these data included, estimated rates of overdiagnosis as a result of screening increase to up to 50%, he argues.

This is important because it can change the decisions women make when invited for screening. In a study also published today, researchers at the University of Sydney explored attitudes to screening in a sample of 50 women. Many of the women were surprised when they were told about overdiagnosis and most said they would attend screening if overdiagnosis rates were 30% or lower, but a rate of 50% made most of them reconsider.

An accompanying editorial points out that the harms of screening will reduce as more effective diagnostic  processes develop to inform less harmful and more personalised treatments. In the meantime, it says women need up to date and transparent information about the benefits and harms of screening to help them make informed choices.

A trial of removing food additives should be considered for hyperactive children

Re-Post for Filing 2008

Contact: Rachael Davies
rdavies@bma.org.uk
44-020-738-36529
BMJ-British Medical Journal

A properly supervised trial eliminating colours and preservatives from the diet of hyperactive children should considered a part of the standard treatment, says an editorial in this week’s BMJ.

Although a substantial body of evidence shows a link between attention deficit hyperactivity disorder (ADHD) and artificial food colourings and preservatives, removing them is still considered as an alternative rather than a standard treatment for ADHD, writes Professor Andrew Kemp from the University of Sydney.

In contrast, despite a lack of evidence for its effectiveness, the use of alternative medicine is widespread—up to 50% of children attending tertiary children’s hospitals in the UK and Australia have used it in the past year.

Of the three main treatments for ADHD in children—drugs, behavioural therapy, and dietary modification—only drugs and dietary modification are supported by data from several trials. Yet, behavioural therapy, which has no scientific evidence base, is still thought of as necessary for “adequate treatment”, he says.

So why, despite evidence to the contrary, does the removal of food additives remain an alternative rather than a standard part of treatment for ADHD, asks Kemp”

Data published in 2007 showed that normal (not hyperactive) children were significantly more hyperactive after they ate a mixture of food colourings and a preservative (sodium benzoate), with obvious implications for children with ADHD.

In light of these findings, the European Food Safety Authority (EFSA) reviewed the evidence linking preservatives and colourings with hyperactive behaviours from 22 studies between 1975 and 1994 and two additional meta-analyses.

16 of the studies reported positive effects in at least some of the children. However, the EFSA pointed out that hyperactivity has a wide range of social and biological causes, and exclusively focusing on food additives may “detract from the provision of adequate treatment” for children with the disorder. But, argues Kemp, to discount the accumulating evidence of dietary factors may also do this.

Increasing numbers of children are taking drugs for hyperactivity—2.4% of children in the state of Western Australia. Removing colours and preservatives is a relatively harmless intervention, so a properly supervised and evaluated trial period of eliminating them should be considered as part of the standard treatment, he concludes.

Suppressive effects of a phytochemical cocktail on prostate cancer growth in vitro and in vivo. Abstract no. A104: 25% reduction in tumor size in 14 days

A commercially available nutrition drink reduces the growth of tumors in a mouse model of human prostate cancer by 25 percent in two weeks, according to researchers from the University of Sydney. The drink, Blueberry Punch, is a mixture of plant-based chemicals – phytochemicals – known to have anti-cancer properties.

“While individual phytochemicals are successful in killing cancer cells, we reasoned that synergistic or additive effects are likely to be achieved when they are combined.”

Singh and her colleagues studied the effect of the beverage on both cancer cell cultures and in mouse models that mimic human prostate cancer. After 72 hours of exposure to increasing concentrations of Blueberry Punch, prostate cancer cells showed a dose-dependent reduction in size and viability when compared with untreated cells, Singh says. After feeding mice a 10 percent solution of the punch for two weeks, the tumors in the test mice were 25 percent smaller than those found in mice that drank only tap water.

Based on these results, the researchers believe Blueberry Punch is now ready for human prostate cancer trials. Because Blueberry Punch is a food product rather than a drug, it is unlikely to have adverse reactions or side effects assuming that the individual is tolerant to all ingredients, Singh says. “The evidence we have provided suggests that this product could be therapeutic, although it requires clinical validation,” Singh said