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 “A lot of women with cancer in one breast decide to have both
breasts removed to try to improve their survival or life
expectancy,” said senior author Dr. Todd M. Tuttle, a surgeon at the
University of Minnesota in Minneapolis.
For some women – such as those at high genetic risk for breast
cancer - removing a still-healthy breast may very well help in the
long run, Tuttle said. But the women in the current study did not
have the BRCA gene mutations that would have greatly increased their
risk of cancer in both breasts.
Tuttle and his coauthors used published data to develop a model for
predicting survival rates over 20 years for women diagnosed with
stage I or II cancer at age 40, 50 or 60.
According to the existing data, more than 98 percent of women
diagnosed with stage I breast cancer will survive at least 10 years,
and 90 percent will survive for 20 years. For stage II breast
cancer, 77 percent survive for at least 10 years and 58 percent
survive at least 20 years.
For all age groups and tumor types in the study, the risk of
developing cancer in the opposite breast after diagnosis was less
than one percent each year, the authors wrote in the Journal of the
National Cancer Institute.
Given how rare breast cancer in the opposite breast is for this
group of women, having both breasts removed at once only increased
life expectancy by at most seven months for women diagnosed with
stage I cancer and less than four months for women with stage II
cancer. Estimates were even lower for older women and women with
estrogen-receptor positive cancers.
“We chose the best group that we could possibly find – women less
than 40, women with estrogen-receptor negative breast cancer, women
with stage I,” Tuttle told Reuters Health by phone. “Even in that
group there was not a meaningful survival benefit.”
Prophylactic mastectomy of the healthy breast has become much more
common in recent years, in part because doctors suggest it and in
part because women believe it will help them in the long run, Tuttle
said.
Given that a double mastectomy essentially doubles the invasiveness
and surgical risk of a one-sided mastectomy, complication rates from
the surgery double as well, he said. The new model did not account
for other factors including surgical complications, cost or quality
of life.
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In an editorial published with the study, Dr. Stephen G. Pauker and
Dr. Mohamed Alseiari write, “Although the survival benefit from
(removing the other breast) is small as demonstrated in this model,
it is greater than zero, which suggests that for some patients even
that small gain may be enough to make (the surgery) a not
unreasonable choice.”
Pauker and Alseiari study clinical decision-making at Tufts Medical
Center in Boston.
For those women very troubled by the 0.7 percent chance of
developing cancer in the second breast, the additional surgery may
be worthwhile.
But from a societal perspective, the cost of the procedure, its
complications, reconstruction and resulting negative effects on body
image may outweigh the modest benefit of the extra surgery, they
write.
Adding quality of life to the model would likely diminish the
benefit further and turn it into a net harm, they write. Ultimately,
the choice should depend on the patient’s unique values and
expectations.
Tuttle reiterated that his hypothetical survival model only applies
to women without the BRCA mutation.
“The group that benefits primarily from contralateral mastectomy is
the ones with hereditary breast cancer,” he said. “I always
recommend that women see a genetic counselor and get the genetic
testing.”
He added, “If you have the mutation, it’s a very reasonable option
to consider.”
SOURCE: http://bit.ly/1l7FxaA, http://bit.ly/1oNicpj Journal of the
National Cancer Institute, August 8, 2014.
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