Silencing the Silent Killer

Doctors report better results, refined methods in breast cancer treatment

By Pascal Barollier

Studies introduced at the annual American Society of Clinical Oncology (ASCO) conference in May showed refinements in treatment for the early stages of breast cancer, the most prevalent cancer in women worldwide.

    In the largest study, conducted on 1,491 women in several countries, the drug docetaxel (Taxotere) reduced the risk of breast cancer recurrence after three years by 32 percent when compared with traditional chemotherapy treatment. The death rate among study subjects was reduced to rates reaching 54 percent, and the chance of recurrence dropped to 50 percent when the cancer had spread to no more than three lymph nodes, according to lead study author Dr. Jean-Marc Nabholtz, head of the Breast Cancer International Research Group. Postsurgical treatment cut death rate by 24 percent.

    The figures "indicate a significant improvement over one of the best standard treatments available today," said Dr. Nabholtz, a professor of medicine at the University of California, Los Angeles.

    Another study of 1,477 women showed that the drug tamoxifen yields better results in early-stage breast cancer treatment when administered after a course of chemotherapy. "Our results show that it is best to wait until chemotherapy is finished before starting tamoxifen, to obtain optimal benefits from the chemotherapy," said Kathy Albain, who led the study at Chicago's Loyola University cancer center.

    Tamoxifen, which slowed the growth of certain mammary tumors, has been used for 20 years in treating patients with advanced breast cancer and has recently been used in treating those in the early stages of the disease, as well.

    Eight years after the study began, women who were given tamoxifen after chemotherapy had a survival rate-without any recurrence-that was 18 percent higher than those who received the two treatments simultaneously.

    Other studies showed for the first time that women who are genetically predisposed to breast or ovarian cancer can reduce their risk of developing the disease by 75 percent by having their ovaries and fallopian tubes removed. This method, recommended for women who are beyond their child-bearing years, "is an option to be considered," said Kenneth Offit of New York's Sloan-Kettering Memorial Cancer Center who studied 173 women whose predisposition to cancer was caused by mutations in BRCA1 and BRCA2 genes.

    "This adds to our preventive arsenal, offering women at high risk of these cancers another option for preventing disease," said ASCO President Larry Norton.

    Dr. Timothy Rebbeck of the University of Pennsylvania came to the same conclusion in a separate study.

    Another independent study led by ASCO recommended caution in the use of anastrazole, an aromatase inhibitor. "The expert panel finds that the available data on the drug are promising but do not support routine use outside of clinical trials," warned Eric Winer, who headed the group evaluating the drug.

    "Patients and physicians can rest assured that tamoxifen remains the best option for use outside of clinical trials, and that it reduces the risk of recurrence and improves overall survival," said Winer of the Dana-Farber Cancer Institute in Boston, Massachusetts.

    Meanwhile, a program to encourage women to undergo mammography screening can reduce breast-cancer fatalities by more than a fifth, a study published in The Lancet says. The research is an overview of four individual trials covering 247,000 Swedish women aged from 38 to 75, who were either given a mammography or not and whose health was then monitored over a long time-nearly 16 years on average.

    Breast cancer deaths among those who had been screened numbered 511, while the toll among those who had not been screened was 584, a difference of 21 percent. The biggest reductions in the death rate were among women aged 55 and above.

    "The advantageous effect of breast screening on breast cancer mortality persists after long-term follow-up," the authors, led by Lennarth Nystrom of Umeaa University, say.

    Cancer experts are embroiled in a verbal war over mammography, a low-dose X-ray that can identify small cancers several years before they develop into lumps detectable by the conventional method of palpation. Nearly two dozen countries have embarked on major programs to encourage women to undergo routine mammograms in order to detect any tumor in its earliest possible stages, thus enhancing their chance of survival.

    But some opinion says these expensive projects are not providing the hoped-for benefits and may even have negative effects by creating a climate of fear. The fierce debate has prompted ASCO and an important data group that provides information for the US National Cancer Institute to carry out a review of the evidence.

    Nystrom's group says the four Swedish trials, which have already been published separately, provide the best confirmation so far that mammograms are useful, because they give a long-term picture, stretching over years. Karen Gelmon of the British Columbia Cancer Agency in Vancouver said the 21-percent reduction was "statistically significant" and that women who are otherwise well, especially those aged 55 to 69, should be encouraged to have a mammogram every two years.

    But whether the investment presented good value was another matter. Money could be spent more usefully in fighting other causes of premature death among women, she implied. "As breast cancer accounts for only about four percent of all deaths annually, even a 21-percent reduction... is barely measurable when all-cause mortality is the endpoint."

    Breast cancer and ovarian cancer have been dubbed women's "silent killers" because they are so often diagnosed too late. The number of women dying from breast cancer in the United States has declined by nearly 30 percent since 1990, but it is unclear whether this is due to the success of awareness campaigns, better diagnostic equipment or better treatment.