Doctors caring for patients with early stage prostate cancer may do better to watch and wait to see if tumors develop rather than engage in aggressive treatment that may do no good, scientists said on Tuesday.

A study in the Journal of the American Medical Association found the risk of dying from prostate cancer in the 10 years after diagnosis fell by more than 60 percent in patients diagnosed between 1992 and 2002 compared with patients diagnosed in the 1970s and 1980s.

But doctors only manage 10 percent of cases conservatively by watching closely and delaying treatment until symptoms demand it.

"When diagnosed, prostate cancer is contained within the prostate in approximately 85 percent of cases, and standard treatment options usually include surgery, radiation or conservative management," the researchers wrote.

Prostate cancer is the second most common cancer in men worldwide after lung cancer, killing 254,000 men each year.

But there are fears that in some countries such as theUnited States, it may now be being overdiagnosed and treated more aggressively than necessary.

All current treatments -- surgery, radiation or hormone therapy -- can cause harm and lead to impotence and incontinence in about a third of patients. The authors of Tuesday's report said with that in mind, doctors and patients should reconsider the watch and wait option.

A study published in August showed routine screening for prostate cancer has led to more than 1 million men in the United States being diagnosed with tumors who might otherwise have suffered no ill effects from them.

For Tuesday's study, Grace Lu-Yao and colleagues at the Cancer Institute of New Jersey studied 14,500 men 65 or older when they were diagnosed -- between 1992 and 2002 -- with early stage prostate cancer and who were cared for without surgery or radiation for 6 months after diagnosis.

They found that after 10 years, 6 percent had died from prostate cancer, far fewer than in results of previous studies dating from 1949 to 1992, when between 15 and 23 percent died within 10 years of being diagnosed.

"Patients tend to over-estimate the effects of treatment. They tend to see cancer as a life-threatening disease and think treatment will save their lives," Lu-Yao, a cancer epidemiologist, said in a telephone interview.

"But prostate cancer is sometimes different from other cancers, and with these early screenings, for a lot of people it really won't cause a problem during their lifetime."

Lu-Yao said the improvement in diagnosis and survival rates could relate to the introduction in 1986 of a widely used blood test that looks for a prostate specific antigen, or PSA.

PSA testing can pick up disease 6 to 13 years before it may otherwise be found, and patients identified in such tests would be expected to live between 6 and 13 years longer because of this lead time, the authors said.

Doctors in the U.S. have routinely recommended PSA screening in men over 50 based on the assumption that early diagnosis and treatment is better than standing by and doing nothing.

                                                                                                                                     2009-09-29

A U.S. study by UT Southwestern Medical Center at Dallas has found that fat from certain foods such ice-cream and burgers heads to the brain.

Once there, the fat molecules trigger the brain to send messages to the body's cells, warning them to ignore the appetite-suppressing signals from leptin and insulin, hormones involved in weight regulation -- for up to three days.

"Normally, our body is primed to say when we've had enough, but that doesn't always happen when we're eating something good," said researcher Deborah Clegg in a statement.

"What we've shown in this study is that someone's entire brain chemistry can change in a very short period of time. Our findings suggest that when you eat something high in fat, your brain gets "hit" with the fatty acids, and you become resistant to insulin and leptin.

"Since you're not being told by the brain to stop eating, you overeat."

The researchers also found that one particular type of fat -- palmitic acid which is found in beef, butter, cheese and milk, -- is particularly effective at instigating this mechanism.

The study was performed on rats and mice but the scientists say their results, published in The Journal of Clinical Investigation, reinforced common dietary recommendations to limit saturated fat intake as "it causes you to eat more."

The study was conducted by exposing rats and mice to fat in different ways -- by injecting various types of fat directly into the brain, infusing fat through the carotid artery or feeding the animals through a stomach tube three times a day.

The animals received the same amount of calories and fat and only the type of fat differed. The types included palmitic acid, monounsaturated fatty acid and unsaturated oleic acid which is found in olive and grapeseed oils.

"The action was very specific to palmitic acid, which is very high in foods that are rich in saturated-fat," said Clegg.

                                                                                                                                        2009-09-29

The findings, reported in the journal Science, are some of the first to link sleep with the development of Alzheimer's, the most common form of dementia.

Researchers at Barnes-Jewish Hospital in St. Louis studied levels of amyloid beta -- a protein that accumulates in the brain of people with Alzheimer's -- in mice genetically engineered to have a version of Alzheimer's disease.

Amyloid levels rose in the brain when the mice were awake, and fell when they slept.

When the researchers prevented the mice from sleeping, it made matters worse, said Dr. David Holtzman of Barnes-Jewish Hospital, who worked on the study.

"Sleep deprivation markedly accelerated amyloid-beta plaque formation," he said in an e-mail.

When the team injected orexin -- a compound that regulates sleep -- into the brains of the mice, the mice stayed awake longer, and amyloid beta levels rose. And when they blocked orexin, these levels decreased.

In people, orexin plays a role in the sleep disorder narcolepsy, which causes excessive sleepiness.

Holtzman said the findings suggest drugs that target orexin may be useful to try as Alzheimer's treatments.

They also reinforce the need to treat sleep disorders, not only because they cause immediate problems, but because they may have a long-term impact on brain health, he said.

Despite decades of research, doctors still have few effective weapons against Alzheimer's, a mind-robbing form of dementia for which there are few effective treatments and no cure. Many treatments that have shown promise in mice have had little effect on humans with Alzheimer's disease.

More than 35 million people globally will suffer from Alzheimer's disease or other forms of dementia in 2010, according to the Alzheimer's Association.

                                                                                                    2009-09-28