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Friday 9th June, 2006
Breast cancer with a certain genetic mutation can
have breast-sparing surgery but should consider
ANN ARBOR, MI ? Women diagnosed with breast cancer who carry
a certain genetic mutation can have breast-sparing surgery but
should consider hormonal treatments to reduce their risk of
Those are the findings of a 10-year study led by researchers
at the University of Michigan Comprehensive Cancer Center. The
study authors found that women with the genetic mutation who had
their ovaries removed or took the anti-estrogen drug tamoxifen
had lower rates of breast cancer recurrence or new breast
cancers in the other breast.
Women who carry a mutation on the BRCA1 or BRCA2 gene are at
an increased risk of breast cancer compared to women without the
mutation. And once diagnosed with breast cancer, they face a
higher rate of a second tumor occurring. Because of this,
questions remain about whether these women should undergo
breast-conserving surgery instead of mastectomy, which removes
the entire breast.
In this study, published in the June 1 issue of the Journal
of Clinical Oncology, researchers from 11 centers looked at 160
women with early breast cancer and the BRCA1 or BRCA2 gene
mutations. The women were treated with lumpectomy, surgery to
remove only the tumor, followed by radiation therapy. These
women were compared to 445 similar women who were treated for
breast cancer but did not carry the genetic mutations.
After 15 years, both groups of women had similar rates of the
tumor reoccurring in the same breast. But among the women with
the BRCA1 or BRCA2 mutations, those who were further treated by
having their ovaries removed, a procedure called oophorectomy,
were less likely to have a recurrence. Similarly, tamoxifen
dropped the risk of same-breast recurrence for the mutation
carriers by 58 percent.
Women with the genetic mutations had a significantly greater
risk of developing breast cancer in the opposite breast than did
the control group. After 15 years, 45 percent of the women with
the mutation who had not undergone oopherectomy developed a
second breast cancer in the other breast, compared to only 9
percent of those women without the genetic mutation.
Women with the mutation who took tamoxifen had a 69 percent
reduction in breast cancer in the opposite breast. Among women
who did not undergo oophorectomy, tamoxifen made a significant
difference: 6 percent of those taking tamoxifen had a second
cancer in the opposite breast after 15 years, compared to 54
percent of those who did not take tamoxifen.
?For women with early stage breast cancer who are BRCA1 or
BRCA2 carriers, our 10-year data suggest that oophorectomy or
tamoxifen in women treated with breast conservation and
radiation therapy help to reduce the risk of recurrences and new
primary cancers in the treated breast to levels comparable to
those observed in women with early stage breast cancer who are
not BRCA1 or BRCA2 carriers,? says lead study author Lori J.
Pierce, M.D., professor of radiation oncology at the U-M Medical
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?However, carriers must understand that the risk of breast
cancer in the opposite breast still remained significantly
greater than in women without a mutation. Thus, it is very
important that women who choose breast preservation discuss with
their doctors surveillance strategies not only of the involved
breast but also in the opposite breast,? she says.
Oophorectomy is a common procedure for women with the BRCA1
or BRCA2 gene mutations because it reduces the risk of ovarian
cancer, which is also higher in women with these mutations.
Tamoxifen is commonly prescribed to treat breast cancer that is
responsive to estrogen.
Many women with the genetic mutations will have both their
breasts removed before cancer develops as a preventive strategy.
After breast cancer develops, bilateral mastectomy reduces the
risk of it recurring by at least 90 percent. But studies have
shown approximately the same number of breast cancer patients
with the mutations choose mastectomy and breast conservation,
suggesting considerable interest in breast conservation among
this group of women.
?We need to look to hormonal therapies that may lead to
greater risk reductions than tamoxifen. For example, recent
studies suggest comparable risk reductions with raloxifene and
tamoxifen but fewer side effects with raloxifene. Studies are
needed to assess the effect drugs such as raloxifene or
aromatase inhibitors have in preventing second tumors in breast
cancer mutation carriers,? Pierce says.
This year, 212,920 women will be diagnosed with breast
cancer. About 1 in 300 people carry the BRCA1 or BRCA2 gene
Funding for the study was from the Breast Cancer Research
Foundation, National Institutes of Health and National Cancer
Journal of Clinical Oncology, June 1, 2006, Vol. 24, No. 16,
Written by Nicole Fawcett