By JR on Thursday, September 18, 2014
TWO medical backflips in one day
Common treatments for prostate cancer could speed the growth of tumours, a major study has warned
Researchers found that steroid drugs which are widely prescribed because they control the disease not only stop working over time - but began to drive the spread of cancer.
The study by the Institute of Cancer Research, The Royal Marsden Foundation trust and the University of Trento in Italy tracked 16 men with advanced prostate cancer in detail.
The research found that use of glucocorticoids - steroid drugs often given alongside hormonal therapy - coincided with the emergence of mutations that led the drug to activate the disease.
Researchers said in future, men with advanced cancer should undergo very regular blood test monitoring to identify such mutations, in order to change their treatment.
They said that "liquid biopsies" analysing tumour DNA circulating in the blood could give an accurate picture of cancer development in individual patients, so treatment could be better targeted.
The study, published in in Science Translational Medicine, used complex genetic analysis of biopsies and blood samples from patients with advanced prostate cancer.
In several patients, use of glucocorticoids coincided with the emergence of androgen receptor mutations and the progression of cancer into more advanced forms.
The study showed that blood tests to measure circulating tumour DNA levels – which is less expensive and invasive than taking repeated samples of tumours with needle biopsies – could be used to monitor the emergence of treatment-resistant prostate cancer.
Study leader Dr Gerhardt Attard, Cancer Research UK Clinician Scientist at The Institute of Cancer Research, London, said: "Our study showed that a steroid treatment given to patients with advanced prostate cancer and often initially very effective started to activate harmful mutations and coincided with the cancer starting to grow again."
Professor Paul Workman, Interim Chief Executive at The Institute of Cancer Research, London, said: "Drug resistance is the single biggest challenge we face in cancer research and treatment, and we are just beginning to understand how its development is driven by evolutionary pressures on tumours.
"This important discovery reveals how some cancer treatments can actually favour the survival of the nastiest cancer cells, and sets out the rationale for repeated monitoring of patients using blood tests, in order to track and intervene in the evolution of their cancers."
Dr Matthew Hobbs, Deputy Director of Research at Prostate Cancer UK, said: "There are currently too few treatment options for men living with advanced stage prostate cancer. Not only do we desperately need to find more treatments for this group of men, we also need to understand more about when those that are available stop working and why."
He said the research was important because it could help to pinpoint the stage at which some drugs stop being effective.
"In the future this could arm doctors with the knowledge they need to ensure that no time is wasted between a drug that stops working for a man and him moving on to another effective treatment," he said.
However he cautioned that the study was an early piece of research, carried out in very few men, with larger studies needed.
Low-calorie sweeteners found in diet drinks RAISE the risk of obesity and diabetes by affecting how the body processes sugar
Millions rely on them to help them stay thin. But low-calorie artificial sweeteners actually raise the risk of obesity, researchers fear.
The popular sugar alternatives found in diet drinks and in sachets in cafes and restaurants may also increase the odds of diabetes.
The sweeteners under the microscope are saccharin, which is found in Sweet’N Low, sucralose, which is found in Splenda, and aspartame, which is found in many diet drinks.
The Israeli researchers that ‘today’s massive, unsupervised consumption’ of artificial sweeteners needs to be reassessed.
The warning at a time when growing concern about the damage done by sugar is likely to mean more people are switching to artificial alternatives.
British experts urged caution, saying that much of the work was done in mice. But they also said that water is the healthiest drink.
The researchers, from the Weizmann Institute of Science, first showed that all three sweeteners made it more difficult for mice to process sugar.
This is known as glucose intolerance and is important because it raises risk of developing diabetes and obesity.
In a study of almost 400 people, the researchers linked artificial sweetener with being fatter and glucose intolerance.
And, worryingly, volunteers who didn’t normally eat or drink artificially-sweetened foods began to become glucose intolerant after just four days of consumption.
The numbers affected were small – just four out of seven men and women in the trial – but the research overall was judged significant enough to be published in Nature one of the world’s most prestigious scientific journals.
Other experiments suggested the sweeteners do the damage by altering type of bacteria in the gut.
While this might seem odd, some of the bugs that live naturally in our digestive system are very good at breaking down food.
If they thrive on artificial sweeteners, this could lead to more energy being extracted from food and more fat being stored – raising the odds of obesity.
Lead researcher Professor Eran Elinav, said: ‘Our relationship with our own individual mix of gut bacteria is a huge factor in determining how the food we eat affects us.
‘Especially intriguing is the link between use of artificial sweeteners - through the bacteria in our guts - to a tendency to develop the very disorders they were designed to prevent.
‘This calls for reassessment of today's massive, unsupervised consumption of these substances.’
The professor has stopped using artificial sweeteners. He has also removed sugar from his diet – but says it is too early to make health recommendations based on his study.
Dr Katarina Kos, a diabetes expert from the University of Exeter, said that larger-scale human studies are ‘urgently required’.
Brian Ratcliffe, professor of nutrition at Robert Gordon University, Aberdeen, said that most of the experiments related to saccharin – which is rarely found in diet fizzy drinks. He said: ‘There seems no reason to suggest that swopping to a diet version of your favourite fizzy drink is unwise.’
Gavin Partington, of the British Soft Drinks Association, said research contradicts ‘the overwhelming body of scientific evidence’.
He said: ‘More than 40 studies have concluded that the use of low-calorie sweeteners do not lead to either an increased risk of obesity or diabetes.
‘Decades of clinical research show that low-calorie sweeteners, such as those in diet drinks, have been found to aid weight control when part of an overall healthy diet and assist with diabetes management.’
The International Sweeteners Association, which represents manufacturers including the maker of Splenda, also strongly rejected the research.