Estrogen
therapy does not cause new cancer in menopausal women with treated
localized breast cancer
Estrogen replacement therapy does not
cause new or recurrent breast cancer in menopausal women with a history
of treated, localized breast cancer, according to an article currently
available online and to be published in the November 1st print issue
of CANCER.
After five years, estrogen replacement therapy
had no adverse effect on survival or compromise of disease-free
states among women with a history of treated localized breast cancer.
These results, which come from one of the longest follow-up trials
to date, provide additional evidence of the safety of such therapy
in menopausal women with treated primary breast cancer --- a group
that has previously largely been denied the health benefits of replacement
therapy.
The researchers conducted a randomized, prospective
clinical trial to evaluate the safety and efficacy of estrogen replacement
therapy in patients with a history of treated stage I or II localized
breast cancer. Women with a history of known estrogen receptor-positive
tumors were specifically excluded from the study. A total of 77
women participated in the randomized arm (34 received therapy, whereas
43 did not). An additional 222 women participated in the non-randomized
arm of the study (22 received therapy, whereas 200 did not).
No statistically significant differences between
the clinical prognostic characteristics of randomized and nonrandomized
patients were observed. Participants were evaluated every three
months for two years, and then every six months for an additional
three years, with clinical and laboratory assessments including
lipid profile, follicular stimulating hormone level, and estradiol
levels. Bone Mineral Density was measured at baseline and annually
for five years.
There was no significant difference in survival
after five years between women who received replacement therapy
and those who did not. Analysis of the randomized group showed no
differences in disease-free survival among women receiving therapy
and those who did not or among women with estrogen receptor-negative
tumors.
Analysis of all 299 participants showed similar
findings. In fact, patients who received replacement therapy were
more likely to enjoy breast cancer-free survival (P=0.04, hazard
ratio=4.08). New or recurrent breast cancer developed in 33 (13.5
percent) women in the no-therapy arm; contralateral new breast cancer
developed in 2 (3.6 percent) women who received replacement therapy.
No difference in disease-free survival was observed among participants
with receptor-negative tumors. There were no deaths and no difference
between therapy and no-therapy groups in the development of other
cancers.
There was modest improvement in bone density
and lipid profiles among women treated with estrogen replacement
therapy. After five years there was significant beneficial effect
on bone mineral density of the hip (P=0.0001) and in high-density
lipoprotein cholesterol in the group treated with replacement therapy.
The authors concluded that this study "provides
prospective data with much longer follow-up than previous series
and reinforced the notion that estrogen replacement therapy does
not compromise disease-free states in patients with curatively treated
breast cancer."
The authors added, "larger prospective,
randomized trials with appropriate statistical power are clearly
very important to define the safety of ERT in this setting and,
perhaps, modify current standards of care for women with a history
of treated primary breast cancer."
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