DOGGONE DOCTOR
British researchers say dogs can tell who's got bladder cancer by sniffing patients' urine
Going to the dogs
PARIS
Dogs have been trained to detect bladder cancer by sniffing urine, using their acute sense of smell to identify a tiny but characteristic odor released by tumors.
British scientists took six dogs of varying ages and breeds and trained them over six months to discriminate among dozens of samples of urine from patients with bladder cancer, from people with other urological diseases, and from healthy individuals.
The dogs were then put through their paces in a carefully devised test. They had to detect a urine sample from a bladder-cancer patient among six "control" samples, nine times over.
Taken as a group, the dogs correctly spotted the positive sample 22 times out of 54--a success rate of 41 percent. The performances ranged from one out of nine by a six-year-old male mongrel to five out of nine by two working-strain cocker spaniels, a male aged 18 months and a female aged two years.
The team, who report their work in the British Medical Journal, says the outcome is "proof of principle." It opens up intriguing paths into detecting early-stage cancer through smell, rather than through chemical tests, scans or invasive diagnostics as is the case today.
The inspiration for the experiment dates 15 years, when a pair of British dermatologists wrote a letter to The Lancet in April 1989 to describe a bizarre case in which a worried dog saved her owner's life. The animal persistently sniffed, and eventually tried to bite, a lesion on the woman's leg. Thus prompted, she went to the doctor, who found that it was skin cancer in its earliest stages. She was successfully treated.
Innovative technological work into cancer-sniffing has also been unfolding. University of Rome scientists last year tested a prototype "electronic nose" that proved to be 100-percent accurate in a breath test of 35 people with advanced lung cancer and 25 others who were healthy. The device works in the same way as hygiene "sniffers" used on the production line in hi-tech food factories to detect the chemical signature of rotting ingredients. These sensors comprise a quartz crystal coated with metal-containing dyes that bind to specific organic (i.e. carbon-based) chemicals. The binding very slightly changes the weight of the crystal, causing it to vibrate at a different frequency, thus triggering a signal.
The theory behind cancer sniffing is that tumors release volatile organic compounds as they grow. Even though the amounts are only tiny, they have a specific signature that can be detected if the olfactory power is strong enough to sense and discriminate.
Cervical-cancer vaccine shows promise
WASHINGTON
Years of clinical trials have yielded promising results for a vaccine that would protect women from a virus that causes cervical cancer.
Four years after being vaccinated, 94 percent of the 755 women who participated in the study were protected against the human variant of the papilloma virus 16 (HPV), according to a report presented at the world conference of the American Society for Microbiology in Washington.
Only seven of the women in the study were infected with HPV, but none showed any precancerous symptoms, according to the study. In comparison, in the group of 750 women injected with a placebo, 111 were infected by the virus and 12 developed precancerous cells.
The research was financed by Merck pharmaceutical laboratories, which expects a green light from United States government regulators to start production this year. GlaxoSmithKline is also working on an anti-HPV vaccine and is hoping for approval from US and British regulating agencies.
Cervical cancer affects 500,000 women around the world each year, and half of them die of the illness, researchers said.
Sunbathing reduces risk of lymph-gland cancer
STOCKHOLM
Contrary to previous belief, sunlight reduces the risk of developing tumors in the lymphatic glands, according to a Swedish study published in the Journal of the National Cancer Institute.
The number of new cases of lymphoma per year has tripled in the past 40 years, and the reason for the rise is largely unknown.
One hypothesis has been that frequent exposure to the sun increases not only the risk of developing skin cancer but also non-Hodgkin's and Hodgkin's lymphoma. That hypothesis is based on the fact that there is an established link between skin cancer and lymphoma. But a fresh study by researchers at Sweden's Karolinska Institute and Uppsala University suggests that sun exposure is not responsible for the link between the two forms of cancer, since frequent exposure to ultraviolet rays seems to reduce the chance of developing lymphoma by 30 to 40 percent.
The study was based on telephone interviews with more than 3,000 patients who were newly diagnosed as having malignant lymphoma, either non-Hodgkin's or Hodgkin's, between 1999 and 2002 in Sweden and Denmark, and just over 3,000 randomly chosen healthy members of the public.
Statistical analysis showed that those who were heavily exposed to sunlight as children or in their 20s were 30 to 40 percent less likely to develop the most common form of lymph-gland cancer, non-Hodgkin's lymphoma. The results for other types of lymphoma could not be statistically confirmed, though they pointed in the same direction.
Vitamin D, which the body produces when exposed to sunlight, could possibly explain the reduced risk, but researchers said they would have to conduct further studies to confirm that.
Karin Ekstroem Smedby, one of the researchers behind the study, said that if the results of the study can be replicated and complemented with additional data, then advice about sunbathing might have to be amended.
"But we haven't looked into the mechanisms behind the effect of sunlight on lymphoma," she said. "More research is needed before we can give advice about the dangers and benefits of sunbathing in a wider perspective."
Gene "signature" can predict breast-cancer recurrence
PARIS
Scientists in the Netherlands say they have developed a powerful diagnostic tool, based on a telltale gene "signature," that could help breast-cancer patients avoid unnecessary follow-up treatment.
The research, reported in The Lancet, focuses on lymph-node-negative breast cancer. If diagnosed in time, up to 70 percent of women who undergo surgery or radiotherapy for this disease are cured. The treatment usually entails follow-up chemotherapy or hormone treatment, routinely recommended as a precaution to prevent recurrence of the cancer. Only about a third of all patients actually need the follow-up therapy, however, which can be aggressive with big side effects.
Dutch doctors believe that the new diagnostic can help pinpoint those women who are genetically more at risk of a recurrence than others, and this could spare low-risk patients from having to undergo unnecessary follow-up treatment. They found a "signature" of protein markers, expressed by 76 genes, which were frequently found among 115 stored tumors taken from patients who had lymph-node-negative breast cancer.
The team, led by Dr. John Foekens of the Erasmus Medical Centre in Rotterdam, then tested the "signature" on the genetic profile of 171 other cancer patients who had initial treatment for their tumor and been carefully monitored over the next five years to see if the cancer had returned. They found the "signature" was 93-percent accurate in predicting those who had had a recurrence within five years, although it was much less precise (48-percent accurate) in predicting patients whose disease did not return in that time.
Several previous studies have also identified gene "signatures" to test for breast cancer, although this is the largest by far. The problem though is that the proposed "signatures" either overlap or are different. At the moment, there is no global agreement as to what should be the common set of genes that should be incorporated in a standard test.
Coffee halves risk of liver cancer
WASHINGTON
Drinking coffee regularly can reduce the risk of liver cancer by more than one half, according to a study carried out in Japan on more than 90,000 people and published on February 16 by the Journal of the National Cancer Institute.
Taking into account anticancer properties of caffeine on lab animals, a team of Japanese researchers analyzed a public-health report spanning a decade, which allowed them to track a large number of patients, many with liver cancer, and their coffee consumption habits. They found that those who rarely or never drank coffee were hit with the cancer in 547.2 cases per 100,000 people, while those drinking three to four cups a day were hit with just 214.6 cases per 100,000. The report tracked 90,452 Japanese--43,109 men and 47,343 women--ages over 40.
In addition to coffee drinking researchers took into account other factors such as hepatitis virus infection, sex, age, diet, lifestyle factors, and previous kidney disease.
Experimental drug tests good against prostate cancer
WASHINGTON
A new experimental vaccine treatment helps the immune system attack tumors and can prolong the lives of men suffering from advanced prostate cancer. Dendreon Corp. of Seattle, Washington, said its immunotherapy drug Provenge proved in tests to extend significantly the lives of men with certain types of prostate cancer.
In the tests, prostate-cancer patients taking the drug lived an average 19 weeks longer than those taking placebo. After three years, surviving Provenge users numbered about three times those who did not take the drug.
The treatment's success also may reinvigorate research into vaccines to be used for treating cancer, scientists said. The drug represents important progress in the 20-year effort to develop a vaccine for battling cancer, according to University of California researcher Eric Small. It "has the potential to provide an important new treatment option for prostate-cancer patients," he said.
"This is clearly some of the strongest evidence we've seen of a clinical benefit," for a therapeutic cancer vaccine, James Gulley of the National Cancer Institute was quoted by The Washington Post as saying.
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