Here's the NY Times report. It contains much of the info seen on C-SPAN:
By LAWRENCE K. ALTMAN
ASHINGTON -- For the first time, a drug has been shown to prevent breast cancer
among women at high risk for the disease, a jubilant group of federal health officials said
Monday.
Women who took the drug, tamoxifen, had 45 percent fewer cases of breast cancer than a group of
women who took a dummy pill, or placebo. The drug helped all age groups in a large study, they
said. The health officials called the study results historic and said they hoped they would lead to
development of drugs to prevent other cancers.
But because tamoxifen also carries risks of life-threatening adverse effects, such as cancer of the
uterus, and blood clots that migrate to the lungs from veins in the legs, women were cautioned not to
rush to demand the drug until statisticians and other experts do further analyses so that doctors can
interpret the findings for individual women.
Such analyses should take about two months, Dr. Harold Varmus, the head of the National Institutes
of Health, said in an interview.
The study was controversial from its beginning because many critics said the drug would have
dangerous side effects. But federal officials stopped the study about a year before its scheduled
completion, because an independent monitoring committee found that the drug's benefits clearly
exceeded those that the experts had predicted in designing it.
Women under age 50 in the study appeared to suffer no excess risk of adverse effects from
tamoxifen, and overall, the tamoxifen users had fewer fractures of the hip, wrist and spine than the
women who received the dummy pill.
But on Monday, some critics of the drug said that it was premature to celebrate, because crucial
questions still needed to be answered. Among these, the National Women's Health Network said in
a news release, are: What, if any, additional risks will be found as the participants are followed for a
longer time? Will there be fewer deaths in the long run? And what are the implications for women not
at high risk for breast cancer?
"As with any medication, the decision to begin tamoxifen therapy is a very complex one," Dr. Leslie
Ford, an official of the National Cancer Institute, said. Ford also said that "even if a woman is at
increased risk of breast cancer, tamoxifen therapy may not be appropriate for her" and "there are no
simple answers."
Because the study was not designed to determine the effects of tamoxifen among women who also
took estrogen as a hormone replacement, the officials said they could offer no recommendations of
the relative benefits and hazards of such therapies.
Also, because the study began before the discovery that alterations in two genes, BRCA1 and 2,
may predispose to breast cancer, the trial could not determine whether tamoxifen had unusual benefit
for women carrying the genes. Tests are now planned to address the question over the next year,
said Dr. Richard Klausner, the head of the cancer institute.
The National Institutes of Health and the National Cancer Institute have spent $50 million to conduct
the study since April 1992 among women 35 and older.
Officials emphasized that the types of adverse effects that occurred in the study were anticipated
before it began and that the incidence did not exceed expectations. However, an unexpected finding
was that tamoxifen did not reduce the number of heart attacks.
Tamoxifen has long been prescribed for women who have been treated for breast cancer, to prevent
or delay recurrence of the disease.
In the study, tamoxifen's benefits began almost immediately and continued for the four years of the
study. But further research will be needed to determine how long a woman should take tamoxifen
and whether safer and even more effective drugs can be found to prevent breast cancer, the officials
said.
Among those that might be tested are newer drugs known as selective estrogen-receptor modifiers,
Klausner said.
The prevention study was one of scores of trials conducted over recent decades at hundreds of
hospitals in the United States and Canada by researchers based at the University of Pittsburgh. An
earlier study provided hints that tamoxifen could prevent as well as treat cancer.
Those who conducted the study are in the process of notifying all participants and had planned to
hold a news conference later this week. But some participants notified reporters and the Philadelphia
Inquirer first reported the news on Sunday.
Doctors have used tamoxifen to treat breast cancer for 25 years and are free to prescribe it for
prevention even without approval from the Food and Drug Administration. But the drug agency
issued a news release saying it could not approve tamoxifen for prevention of breast cancer until it
had thoroughly reviewed the information from the study. The FDA pledged to finish such a review
within six months of receipt of the information.
Zeneca Pharmaceuticals of Wilmington, Delaware manufactures tamoxifen, which is one of the most
widely prescribed anti-cancer drugs in the world. Women who took tamoxifen in the study took two
pills for a total of 20 milligrams a day. A month's supply costs from $80 to $100 in the United
States.
Because the risk of breast cancer increases with age, women aged 60 or older qualified to
participate in the study on the basis of age alone. At age 60, about 17 of every 1,000 women are
expected to develop breast cancer within five years.
Women aged 35 to 60 were included if they were judged at high risk based on computer
calculations of such factors as the number of first-degree relatives who had breast cancer; the
number of breast biopsies undergone; age at which a first giving birth; age at which periods began;
and whether the woman had a type of noninvasive breast cancer known as lobular carcinoma in situ.
In the trial, invasive breast cancers developed in 85 of the healthy women who took tamoxifen,
compared with 154 cases among the women who took the placebo.
Eight participants died from breast cancer. Of these, three were among tamoxifen users and five
were in the placebo group.
The findings suggested that women 50 and older had a greater benefit from tamoxifen than younger
women did, but this group was at increased risk for the serious adverse effects such as uterine
cancer and blood clots.
The adverse effects that were greater among the tamoxifen users than the placebo group included
uterine cancer (33 cases vs. 14); pulmonary embolism, or blood clots in the lung (17 cases vs. six);
and blood clots in major veins (30 cases vs. 19).
The proportion of women in the United States who would have qualified for the study were as
follows: at age 35, three in 1,000; at age 40, 27 in 1,000; at age 50, 93 in 1,000; and at age 55, 125
in 1,000.
Although the cancer institute said extensive efforts had been made to enroll minorities in the study,
blacks, Asians, Hispanics and other minority groups comprised only 3 percent of the total.
In 1998, health officials anticipate that breast cancer will be diagnosed in more than 178,000 women
in the United States, and that 43,500 women will die of the disease.
In summarizing the study, Klausner said it "tells us that it is possible to prevent breast cancer and that
tamoxifen is far from ideal." The study, he added, "is not an end, but rather a very propitious
beginning" in finding improved prevention for breast cancer and other types of cancer. |
