New analysis shows that therapy can benefit patients even years after
TORONTO, March 10 /CNW/ - Women may reduce their risk of breast cancer
recurrence by starting treatment with letrozole anywhere from one to
seven years after finishing treatment with tamoxifen, according to new
analysis from a landmark breast cancer clinical trial.
The original trial involving 5,187 women found that post-menopausal
survivors of early-stage breast cancer who took letrozole after completing an
initial five years of tamoxifen therapy had a significantly reduced risk of
cancer recurrence compared to women taking a placebo. The study was halted
early because of the positive results and those on placebo (2,383 women) were
offered letrozole therapy. Within the placebo group, 1,579 women chose to
switch to letrozole therapy and 804 chose not to. The trial was led by the
National Cancer Institute of Canada Clinical Trials Group, which is funded in
part by the Canadian Cancer Society.
In a recent follow-up analysis of this study, researchers evaluated a
subset of women who were in the original placebo group. The new analysis found
that women who started letrozole therapy several years (one to seven years)
after completing tamoxifen therapy had a 63% reduced risk of breast cancer
recurrence. In addition, the women had a 61% reduced risk of the cancer
spreading to other areas of the body, and importantly a 77% reduction in new
cancer in the opposite breast, a potentially important preventive effect. The
results are published in the March 10 online edition of the Journal of
"This finding shows that women can benefit from this type of additional
therapy, even years after their primary therapy" says Dr. Paul Goss, lead
investigator of the original study, director of breast cancer research at
Massachusetts General Hospital and professor of medicine at Harvard Medical
School. "This is important information about follow-up treatment options and
underscores the need for breast cancer survivors and physicians to continue to
discuss ways to reduce their risk of cancer recurrence."
The analysis evaluated a subset of 2,383 women who were in the placebo
group. Of these women, 1,579 chose to switch to letrozole therapy and
804 chose not to.
A second analysis, being published at the same time in the online edition
of the Annals of Oncology, shows that women originally assigned to the
letrozole group continue to have better outcomes than those who were
originally assigned to placebo. These benefits remain even after accounting
for the improved outcomes of women originally assigned to placebo who later
switched to letrozole therapy.
A form of hormone therapy for the treatment of breast cancer, letrozole
works by limiting the ability of an enzyme called aromatase to produce
estrogen, a major growth stimulant in many breast cancers.
Breast cancer is the most common cancer among Canadian women, in 2007, an
estimated 22,300 women will be diagnosed with breast cancer and 5,300 will die
The Canadian Cancer Society is a national community-based organization of
volunteers whose mission is to eradicate cancer and to enhance the quality of
life of people living with cancer. It is the largest charitable funder of
cancer research in Canada. This year, the Society is funding close to
$47 million in leading-edge research projects across the country. When you
want to know more about cancer, visit our website at www.cancer.ca or call our
toll-free, bilingual Cancer Information Service at 1 888 939-3333.
Dr. Paul Goss will be available for interviews. Please contact Stacy
Neale at Massachusetts General Hospital at 617 643-3907
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For further information: Karen Ramlall, Manager, Communications, (416)