"The study demonstrates that elevated concentrations of CRP are strongly associated with the development of colon cancer in individuals believed to be free of this disease at baseline," said a summary of the findings. The risk of colon cancer was found to be "higher in persons in the highest versus the lowest quartile of CRP (2.5 times increased risk). In nonsmokers, the corresponding association was stronger," said the authors. "Additional studies are needed to confirm these findings and to determine the implications on screening and prevention of colon cancer," they concluded.

    The study was published in the Journal of the American Medical Association.

BARBITURATE SLOWS DOWN ITS PROGRESSION

WASHINGTON

A barbiturate formerly used to treat anxiety could slow the progression or block the growth of colon cancer, US researchers said. Their experimental mode of colon cancer, in cell cultures and animal studies, demonstrated the drug Nembutal "can suppress activity in colon cancer cells the same way it inhibits certain kinds of neurotransmissions in the brain and central nervous system."

    "This is the first experimental evidence that Nembutal is a potent inhibitor of colon-cancer metastasis," said the study's first author Premal Thaker, a gynecologic oncology fellow at the University of Texas M. D. Anderson Cancer Center. But while the findings may have threapeutic implications, "more work needs to be done before we know that," he said.

    Researchers recently found that colon-cancer cells' surfaces are studded with receptors for gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter. Thaker and other M. D. Anderson researchers tested whether colon and ovarian cancer cells in the laboratory also contain GABA receptors and what effect Nembutal would have on those cells. They then tested the drug in mice that had been injected with colon cancer known to feature the GABA receptor. Four of 10 mice treated with the drug developed primary tumors as against eight of 10 that did not receive the drug.

STUDY LINKS HEAVY ANTIBIOTIC USE, BREAST CANCER

CHICAGO

Women among the heaviest users of antibiotics may be at greater risk for breast cancer, according to a US study, which showed that women who had taken antibiotics for 500 days over a 17-year period were twice as likely to develop breast cancer as women who had taken none.

    Women who took up to 500 antibiotics over the same period were about 1.5 times more likely to develop this type of cancer as nonusers, according to the study of more than 10,000 women published in the Journal of the American Medical Association. The risk grew with longer-duration antibiotic use. Results were the same for different kinds of antibiotics.

    The study did not explain the link, but the authors gave a number of possibilities.

    "It may be that women who take a lot of antibiotics have some other processes happening in their bodies, such as a weak immune response or a hormonal imbalance, which may be an underlying cause of breast cancer," said paper coauthor Christine Velicer of the Center for Health Studies in Seattle, Washington. Also, antibiotics may harm bacteria in the intestine, preventing certain foods from protecting the body against cancer, she suggested.

    The authors said it was too early to draw conclusions about the medical and public-health implications of their findings, but called for further research to explore the reasons for the link.

    "This is not the time to say all antibiotics are bad," said coauthor John Potter, director of the Public Health Sciences Division at Fred Hutchinson Cancer Research Center. "Antibiotics are an extremely useful tool for the treatment of infection, but they must be used appropriately."

    In an accompanying editorial, two epidemiologists at the University of Pittsburgh in Pennsylvania described the findings as "worrisome," noting that "antibiotic use is common and sometimes nonessential. "Thus, if real, the risk of breast cancer attributable to the use of antibiotics could be large and partially preventable."

    The study was based on 2,266 women with breast cancer and 7,900 healthy controls over 19, some of whom had prescription drug records going back 24 years.

BREAKTHROUGH IN LIVER CANCER TREATMENT

SINGAPORE

Doctors in Singapore have made a potential major breakthrough in the treatment of liver cancer that offers hope to patients unable to undergo traditional heavy drug and radiation procedures.

    Singapore General Hospital (SGH) is looking for terminally ill patients who cannot undergo normal procedures because of their harsh effects to trial the new treatment, the Straits Times reported.

    The new treatment uses the same drugs as existing medication but these are administered via a different method-injecting silicon chips into the tumor with a syringe. The biodegradable chips are inserted into the patient's body in the form of a coarse powder that will dissolve within a few weeks. Each chip holds radioactive isotopes that will destroy cells within eight millimeters (0.3 inches), minimizing the extent of collateral damage to healthy cells around the tumor.

    Pierce Chow, SGH director of experimental surgery, said tests carried out on mice and pigs have shown the new treatment is highly effective.

    Chow said that if the human trials prove successful, the treatment will be available on the market in three years and could later be developed to treat all solid cancers, such as breast, pancreatic, ovarian, cervical, and lung.

PSA TEST NOT ACCURATE

WELLINGTON

Tests for prostate cancer were not reliable enough to allow for a nationwide screening program of men, a report of New Zealand's National Health Committee (NHC) said.

    Api Talemaitoga, NHC member and general practitioner, said the prostate-specific antigen or PSA blood test may detect prostate cancer but had a significant error rate. "What it won't do is tell us accurately enough which cancers are slow-growing and not life-threatening and which are aggressive," he said.

    The report showed that of every 1,000 men who have a PSA test, 136 will test positive, but over time, 95 of these will be found not to have cancer. The test will also miss prostate cancer in 15 men.

    Talemaitoga said most men with prostate cancer would not die from it. About 90 percent of men diagnosed with early stage prostate cancer would still be alive 10 years after being diagnosed, even without treatment. He said most men who had a positive PSA test and had treatment ended up with a poorer quality of life than they would have had if they hadn't had any treatment, which can be hormone therapy, radiotherapy, or surgery.

GENETIC TEST PREDICTS RESPONSE TO GEFITINIB

WASHINGTON

Researchers have discovered gene mutations that identify which lung cancer patients will respond to the drug gefitinib (Iressa), found to radically reduce tumors in a general trial in only 14 percent of patients.

    "This discovery will help us significantly improve the treatment of many lung cancer patients and is also an important next step in the molecular targeting of cancer drugs," said Dr. Daniel Haber, director of the Massachusetts General Hospital (MGH) Cancer Center.

    The type of cancer-advanced nonsmall-cell lung cancer (NSCLC)-is the leading cause of cancer deaths in the US, and causes 85 percent of lung cancers, researchers said. Tens of thousands of lung cancer patients could benefit from the method, detailed in the May 20 edition of the New England Journal of Medicine.

    In a major clinical trial, while the drug Iressa caused tumors to shrink significantly in only 13.6 percent of patients, some of the responses were rapid and dramatic, according to the study.

    The Federal Drug Administration had approved the drug since no other treatment existed for NSCLC patients in whom standard chemotherapy has failed.

    Iressa acts by disabling the epidermal growth factor receptor (EGFR) on the surface of lung cancer cells, halting a sequence of signals that can lead to the rampant growth typical of a malignant tumor. Scientists therefore screened tumor samples from patients in the trial using Iressa to hunt for mutations in the EGFR gene.

    "Understanding these mutations has helped us define the molecular basis of a type of lung cancer that relies on a particular signaling pathway which can be blocked," said Haber, senior author of the paper. Haber is also a professor of medicine at Harvard Medical School.

    A related research by Harvard's Dana-Farber Cancer Institute also found that the gene mutations that best responded to the treatment were more prevalent in women, in Japanese patients, and in patients with adenocarcinoma.

    Use of the drug imanitib (GleevecTM), which also works to target a specific, mutated tyrosine kinase, has been successful in relatively rare conditions such as a certain leukemia and digestive-system tumor, said coauthor Dr. William Sellers.

    However, the new study "shows that it can be effective for a common form of cancer as well," Sellers said.