Emerging
Breast Cancer Therapy Evidence Noted
A new study reported in the medical journal The
Lancet offers more evidence for a move away from tamoxifen as the
standard medication for postmenopausal women with early breast cancer whose
tumor is fueled by estrogen.
Data from two trials conducted in Austria including more
than 3,000 women found a 40 percent reduction in "events" - such as a new breast
cancer or a spread of the tumor to another part of the body - for those who
switched to a medication called an aromatase inhibitor after two years of tamoxifen
therapy, compared to women who continued taking tamoxifen.
The study provides additional support for a treatment "which
is not only a standard in Europe but also in the United States," says study
author Dr. Raimund Jakesz, a professor of surgery at Vienna Medical University.
But whether tamoxifen should be replaced entirely by aromatase
inhibitors such as anastrazole, the one used in the European trials, "is an
unsolved problem," Dr. Jakesz notes.
Both tamoxifen and anastrazole prevent estrogen from spurring
cancer growth - tamoxifen by blocking it from reaching the cancer cells, and
anastrazole by stopping estrogen's production by body tissues other than the
ovaries.
The treatment is limited to postmenopausal women because
their ovaries have stopped producing estrogen.
Several studies, the largest of which included more than
6,000 women, have shown that switching from tamoxifen to an aromatase inhibitor
after two years of tamoxifen therapy has a positive effect like that seen in
the Austrian study, says Dr. Timothy Hobday, professor of oncology and director
of the breast program at the Mayo Clinic College of Medicine.
"Making the switch is supported by the evidence, but it
doesn't tell us what is the optimum thing to do with a patient starting from
zero," he says. "The unanswerable question now is whether to go with an aromatase
inhibitor at once or after a period of time."
A panel of experts convened by the American
Society of Clinical Oncology says that aromatase inhibitor treatment "should
be strongly considered," Dr. Hobday explains. "But their assessment does
not come down on when to use them."
A number of factors must be considered before prescribing
an aromatase inhibitor, he says. One is cost, as aromatase inhibitors are more
expensive than tamoxifen.
And a major medical issue is that aromatase inhibitors "have
a negative effect on bone density," he says. There has been a significant increase
in fractures in women who took the medications in studies, Dr. Hobday points
out.
"So what it comes down to is a case-by-case discussion -
of the cost, of side effects, of an individual's breast cancer risk, of her
bone density, and the characteristics of her breast cancer," he says.
An aromatase inhibitor "makes more of a difference in higher-risk
patients, those with bigger tumors or cancers that have spread to the lymph
nodes," he says.
Always consult your physician for more information.
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A new study in the Journal of the
American Medical Association (JAMA) finds that breastfeeding
infants may reduce a child's likelihood of growing up to need eyeglasses.
Researchers, in a comparison of breast-fed infants with
formula-fed babies, found that breast-fed infants were slightly less likely
to be nearsighted at ages 10 to 12.
"It may have to do with some constituents in breast milk,
but we can't be sure," says Dr. Richard Stone, an ophthalmologist at the
University of Pennsylvania and a co-author of the research letter.
Dr. Stone suggests that a substance in breast milk, docosahexaenoic
acid, or DHA, may underlie the decreased risk of myopia.
DHA is a fatty acid crucial for the growth and functional
brain development in infants and it is also required for maintenance of normal
brain functioning in adults.
It is also important, the study authors note, for the
development of photoreceptor cells in the retina, which play a major role
in whether children become nearsighted.
The retina lines the inner eyeball and is connected by
the optic nerve to the brain.
The eye's lens focuses light on the retina, which then
converts this light into signals sent to the brain.
In nearsightedness, the eyeball is too long and light
rays focus in front of the retina, rather than on it, causing the person
to be able to see objects up close but not at a distance.
In developed countries, nearsightedness is the leading
cause of visual impairment, the authors note, and in the US more than 30
million adults are nearsighted.
The prevalence of myopia has been increasing among urban
Asian children, Dr. Stone adds.
While the study is believed to be the first to observe
an association between breastfeeding and myopia, other studies have found
that breastfeeding is good for the development of children's eyes and is
associated with better school performance by children.
Several of these studies have been conducted by scientists
at the Retina Foundation of the Southwest in Dallas, Texas.
Dennis Hoffman, director of the visual biochemistry lab
at the foundation, says the new study findings are consistent with those
done by his group.
"We've shown that breast-fed infants have improved visual
maturation at one and a half years, compared to those fed formula," he adds.
Dr. Stone and his colleagues, led by Dr. Yap-Seng Chong
of the National University of Singapore, evaluated 797 Singapore children
at ages 10 to 12, including 418 who had been exclusively breast-fed and 379
who had not been.
While 62 percent of the breast-fed children had myopia,
or nearsightedness, 69 percent of those not breast-fed did. "It's really
a modest effect," Dr. Stone explains.
Even after the researchers controlled for factors such
as the parents' nearsightedness, maternal age at delivery, and birth weight,
the association still held.
Always consult your physician for more information.
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