Saturday, April 19, 2008

The Junk juggernaut rolls on

Post below lifted from Prof. Brignell. See the original for links

It is rather a depressing thought that the Telegraph is the nearest thing that Britain has to a serious newspaper. This week it has featured an outbreak of empty scares based on meta-studies, absurdly small studies and, of course, ridiculous relative risks (RR).

The first was a scare involving a popular vehicle for of self dosing, vitamins. While it is clear that people on a normal diet with a normal metabolism are wasting their money on these supplements, this is no excuse for spreading unnecessary alarm. With one possible exception, extra vitamins are simply useless. The exception is vitamin A. While a deficiency of this compound can cause serious diseases, including childhood blindness and death, an excess can suppress growth; stop menstruation; damage red blood corpuscles and cause skin rashes, headaches, nausea, and jaundice. Nevertheless, a meta-study yielding RRs of 1.16 or less adds nothing to the sum of human happiness and merely fuels pointless scare journalism.

Breast cancer has long been a favourite of the scare-mongers. For understandable reasons it roused fear in all women. It is frequently used to provide ammunition for the zealots, so the research tends to be directed towards their favourite targets. Now we are told that one glass of wine a day increases the risk of breast cancer (RR 1.07). Sandy tells about the provenance of this vital "research". In the very same week other “experts” picked on another favourite target, obesity. A small study (Trojan Number 547) indicated that fat women with breast cancer are more likely to die than their slim sisters (RR about 1.4). We are not told just how many were regarded as obese, but even if it were about a half of them, the number of excess deaths would be of the order of 12.

As we have observed before, small studies are not just useless, they are malign, as the phenomenon of funnel plots reveals.

Just in case you did not get the message from our sponsors, the risk of Alzheimer’s is increased for smokers, drinkers and those with raised cholesterol. The inclusion of tobacco is interesting, because before the Great Censorship, it was widely accepted that smokers were half as likely to get Alzheimer’s as non-smokers (likewise Parkinson’s to boot). Indeed, this promoted one of the first uses of the word paradox as a paranym. What a strange coincidence it is that the causes of these diseases all happen to be the favourite targets of various groups of zealots and not something else, such as lettuce.

New drug shrinks breast cancer

A NEW breast cancer drug has shown impressive results in shrinking tumours before surgery. Lapatinib (Tyverb) is licensed in the US for advanced breast cancer but not in the European Union. It is similar to Herceptin in the way that it works – it inhibits the action of an emzyme that prompts the tumour to grow.

At the European Breast Cancer Conference in Berlin, Angel Rodriguez, of Baylor College of Medicine in Houston, Texas, reported on a trial in which lapatinib was given to 45 women for six weeks before they underwent surgery. The tumours shrank by an average of more than 60 per cent, and the drug also cut the number of breast cancer stem cells.

This was important, Dr Rodriguez said, because such cells had proved resistant to other drugs used before surgery. Indeed, the effect of conventional drugs was to increase the number of stem cells and enhance tumour growth. “We were excited to see that the results with lapatinib were different,” he said. Cancer stem cells help to maintain the malignant tissue in the tumour by regenerating it after attack from chemotherapy drugs.

“This indicates that the stem cells themselves should be the specific target of chemotherapy drugs,” said Dr Rodriguez. “Rather than the broad-brush approach, in which cells are killed indiscriminately, targeting the stem cells may be more effective and also prevent some of the unpleasant side-effects associated with conventional chemotherapy treatment. “This is an exciting finding and we will be starting further studies on stem cells in order to confirm it. This finding should also apply to other types of cancers, and research of tumour-initiating stem cells in other cancers is ongoing,” he said.

These include studies in lung, colon, head and neck, gastric, oesophageal, and bladder cancer and lymphoma, among others.

Carolyn Rogers, a clinical nurse specialist at Breast Cancer Care, said: “Lapatinib is being considered for use in secondary breast cancer following clinical trials, but to date there is no strong evidence to show its suitability in treating primary breast cancer. “Dr Rodriguez’s study provides an interesting insight into how lapatinib could be used in early breast cancer. However, with a sample of just 45 patients it is clear that much more work needs to be done to gain statistically significant findings. Further trials are under way but it will be many years before we see the full results of these. Current approved treatment options are very successful, with survival rates increasing year on year.”


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