The findings will be published Saturday in The Lancet, the world's leading independent general medical journal.

    Researchers found that 15 percent to 25 percent of the women who have the HER-2 receptor positive type of early breast cancer could benefit from Herceptin following standard chemotherapy treatment.

    British government's health advisory body, the National Institute for Health and Clinical Excellence, recommends that women with this type of cancer receive Herceptin following surgery, chemotherapy and radiotherapy, providing their heart function meets certain criteria.

    Ian Smith and colleagues from the Royal Marsden Hospital, London, randomly selected 1,703 women to receive Herceptin for one year after surgery and chemotherapy, while another 1,698 women received no drug after surgery and chemotherapy. All the study participants had HER2-positive breast cancer and were followed for two years.

    The researchers found that more deaths occurred in the observation group than in the drug group, corresponding to a survival rate of 2.7 percent after three years.

    However there were more serious side effects on the group receiving Herceptin, namely cardiac damage.

    "That is a problem. It has to be monitored carefully, particularly in patients who have some underlying heart disease," said Lauren Cassell, a breast surgeon at Lenox Hill Hospital in New York City.

    But an accompanying comment paper in the journal points out that "the risk of cardiac damage seems trivial compared with that of breast cancer recurrence."

    (Agencies)