pill that prevents breast cancer in high-risk women, does
not appear in the long run to save many lives, U.S.
researchers reported on Monday. Women at the highest
risk of breast cancer do appear to live longer if they
take tamoxifen, the researchers report in the latest issue
of the journal Cancer.
But for women at
the low end of the high-risk group, the sometimes
serious side effects of tamoxifen outweigh the benefits, Joy
Melnikow of the University of California, Davis, and
colleagues reported. Tamoxifen can cause blood clots
and uterine cancer.
"We found that
for women at the lower end of the high-risk range for
developing breast cancer, there is a very small likelihood
that taking tamoxifen will reduce mortality," Melnikow
said in a statement.
Melnikow and her
colleagues calculated that tamoxifen can extend life
expectancy only when a woman's five-year risk of developing
breast cancer is 3% or higher. This is especially true
for women who have not had a hysterectomy and thus
risk endometrial cancer from taking tamoxifen.
Many women are in
any case switching to a newer class of drugs known as
aromatase inhibitors to treat breast cancer or to the
osteoporosis drug raloxifene to prevent it.
by Eli Lilly under the name Evista, has been shown to
prevent breast cancer as well as tamoxifen does, without
causing as many blood clots, cataracts, or cases of
researchers reported that women with breast cancer who
switched to Pfizer's drug Aromasin after taking
tamoxifen were 17% less likely to die.
estrogen, which can help fuel the growth of tumors in
considered at high risk of breast cancer--usually
meaning they have a close relative with breast cancer
or have had several suspicious-looking lumps or
other conditions--tamoxifen reduced their risk
of breast cancer by 49%.
generically as exemestane, and similar drugs inhibit the
enzyme aromatase, which is needed to produce estrogen. The
aromatase inhibitors are now being used just after
breast cancer surgery instead of tamoxifen in many
women to keep the disease from returning.
inhibitors are not approved for prevention of breast cancer.
sold by AstraZeneca under the name Nolvadex but is now
marketed by several generic drugmakers. It remains the only
drug approved for use in preventing breast cancer in
women who have not yet reached menopause.
Breast cancer is
the second leading cause of cancer death among U.S.
women, after lung cancer. More than 200,000 people are
diagnosed and another roughly 40,000 die from it each
year, according to the American Cancer Society. Some
studies have shown that lesbians are at a higher risk
of breast cancer than their heterosexual peers. (Reuters)