Monday, September 26, 2011

Medical optimism gone mad

A London hospital’s trial of a prostate cancer drug has been stopped early because it was so successful doctors felt it would be "unethical" to deny the treatment to other patients.

But that is absurd. As Ioannides and others now often point out, the early results of a research project are often not typical and the effect observed in the research below was actually quite small in absolute terms. It is only the relative results that look good and even the .3 they report below is dismally short of the 2.0 that the Federal Reference Manual on Scientific Evidence, Second Edition says (p. 384) is the threshold for concluding that an agent was more likely than not the cause of an effect.

Even statistical correlations far stronger than anything found in medical research may disappear if more data is used. A remarkable example from Sociology: below:

"The modern literature on hate crimes began with a remarkable 1933 book by Arthur Raper titled The Tragedy of Lynching. Raper assembled data on the number of lynchings each year in the South and on the price of an acre's yield of cotton. He calculated the correlation coefficient between the two series at -0.532. In other words, when the economy was doing well, the number of lynchings was lower.... In 2001, Donald Green, Laurence McFalls, and Jennifer Smith published a paper that demolished the alleged connection between economic conditions and lynchings in Raper's data. Raper had the misfortune of stopping his analysis in 1929. After the Great Depression hit, the price of cotton plummeted and economic conditions deteriorated, yet lynchings continued to fall. The correlation disappeared altogether when more years of data were added."

So we must be sure to base our conclusions on ALL the data not just a hasty first bite at it

Medics halted tests of the life-extending drug because it would have been “unethical” not to offer the treatment to all 922 cancer sufferers taking part in the trial.

Patients who were given the drug found that it eased pain and caused only minor side effects.

The new drug accurately targets tumours using alpha radiation, which doctors conducting the study said is the most effective form of radiation to eliminate cancer because it limits damage to surrounding tissue. Dr Chris Parker, lead researcher on the project at the Royal Marsden Hospital, said: “It’s more damaging. It takes one, two, three hits to kill a cancer cell compared with thousands of hits for beta particles.”

The drug, Radium-223 Chloride – known as Alpharadin TM – will also do less damage to surrounding tissue because it accurately targets calls, the doctors said. Speaking at an international gathering of cancer experts, Dr Parker, a consultant clinical oncologist, said: “They have such a tiny range, a few millionths of a metre. So we can be sure that the damage is being done where it should be.”

Patients taking the drug has a 30 per cent lower rate of death compared top patients taking a placebo pill. “It would have been unethical not to offer the active treatment to those taking placebo,” Dr. Parker said.

Radium-223 has “a completely different safety profile” to chemotherapy, he added.

The trial’s results were presented this week at the 2011 European Multidisciplinary Cancer Congress in Stockholm.

The researchers, who have pointed out the urgent need for an effective treatment for prostate cancer, will now submit their findings for approval by regulators.

Prof Gillies McKenna, Cancer Research UK’s radiotherapy expert said: “This appears to be an important study using a highly targeted form of radiation to treat prostate cancer that has spread to the bones.

“This research looks very promising and could be an important addition to approaches available to treat secondary tumours – and should be investigated further.”


The cancer risk in your 'healthy' glass of fruit juice which has so much sugar it could bring on tumours

You can't win!

It's supposed to be the healthy way to start the day. But a glass of juice might not be as beneficial as you think – and could even be harmful. Scientists claim fruit juice contains so much sugar it actually increases the risk of certain cancers, rather than preventing them.

In fact, by the time the drink has been processed and packaged, many of the ingredients in fruit that protect against tumours have been lost, they say.

Australian researchers had sought to establish how effective different fruits, vegetables and juices were at preventing the development of bowel cancer. They examined the diets of 2,200 adults, who filled in a questionnaire detailing their daily eating habits. The team then tracked the participants for two years to see how many of them developed the disease.

Unsurprisingly they found that eating apples, sprouts, cauliflower or broccoli on a daily basis all reduced the likelihood.

However, those who consumed lots of fruit juice had a higher risk.

The research, published in the Journal of the American Dietetic Association, found that those drinking more than three glasses a day were more likely to develop rectal cancer, a form of bowel cancer.

Scientists believe the high sugar content in juice may trigger certain tumours.

The Perth team also said that many things found in fruit which help protect against bowel cancer – including fibre, vitamin C and chemicals known as antioxidants – are lost during the juice’s processing.

For years, Department of Health guidelines have advised the public to eat five portions of fruit and veg a day, which can include a glass of juice.

But British researchers claimed earlier this year that fruit juice contains too much sugar to be counted as one of the five. The scientists, of Bangor University, Wales, said people would be better off eating prunes or other dried fruit, as even freshly-squeezed juice contains as much as five teaspoons of sugar per glass.

However, other experts suggest that people shouldn’t shun fruit juice completely, as it is still healthier than other drinks.

Nell Barrie, of Cancer Research UK, said of the latest research: ‘This isn’t a large study, and it doesn’t give us clear answers about whether different fruits and vegetables affect the risk of cancer in parts of the bowel.

‘It’s very tricky to tease apart the effects of a person’s diet on their risk of bowel cancer, but reliable evidence shows that eating lots of red and processed meats increases the risk, while eating plenty of high-fibre foods can reduce the risk.

‘Many fruits and vegetables are a good source of fibre, and eating a diet that’s high in fruits and vegetables could reduce the risk of other types of cancer as well – so it’s a good idea to get plenty of them in your diet.’


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