Letrozole Reduces the Risk of Post-Surgery Recurrence of Early Breast Cancer When Compared With Tamoxifen, Study Shows
St. Gallen, Switzerland (ots/PRNewswire)
In postmenopausal women with early breast cancer, letrozole offers better post-surgery protection against breast cancer recurrence than does tamoxifen, the current standard of care, according to data presented today at the Primary Therapy of Early Breast Cancer 9th International Conference in St. Gallen, Switzerland. The data from the Breast International Group (BIG) 1-98 Trial showed a significant difference in disease-free survival (DFS) in favor of letrozole.
"The results of BIG 1-98 are of great importance for the majority patients with breast cancer. Letrozole reduced the risk of cancer recurrence by 19% beyond the risk reduction achieved by tamoxifen. We now have an additional tool to improve the outcome for postmenopausal women with hormone sensitive breast cancer. Together with optimal surgery, followed by chemotherapy and radiotherapy if needed, incorporation of letrozole in the treatment plan is a step forward in the patients' way of remaining disease from cancer. Further investigations and longer follow-up are necessary to optimize the use of letrozole in order establish longterm safety and tolerability of the drug and to further improve its treatment benefits," says PD Dr. Thurlimann, BIG 1-98 Trial study chair.
BIG 1-98 is the first clinical trial ever designed to incorporate both a head-to-head comparison of letrozole with tamoxifen and a sequencing of both agents, during the first five years following breast cancer surgery, to determine the most effective approach to minimizing the risk of breast cancer recurrence.
The study compares:
- five years of tamoxifen versus five years of letrozole;
- tamoxifen for two years followed by letrozole for three years
- letrozole for two years followed by tamoxifen for three yearsData from the study are expected to answer important questions regarding the optimal sequencing of aromatase inhibitor therapy in postmenopausal women with endocrineresponsive early breast cancer.
Methods and Results
BIG 1-98 is a multinational Phase III double-blind, randomized multicenter trial that is being conducted in 27 countries and involves more than 8000 postmenopausal women with early breast cancer who have hormone receptor-positive tumors. A primary goal of the study was to determine if letrozole could reduce the risk of a disease-free survival event (breast cancer relapse, occurrence of a second (non-breast) malignancy or death without recurrence) compared with tamoxifen. At a median follow-up of 26 months the study shows that, compared with tamoxifen, letrozole reduced the risk of such events by 19%. Among the 4003 patients in the letrozole group, 84.0% remained alive and disease-free at five years compared with 81.4% of the 4007 patients in the tamoxifen group.
There was also a difference in side effects between letrozole and
tamoxifen.
- More on tamoxifen
-- venous thrombosis and embolism (clots)
-- vaginal bleeding more often and led to more endometrial
abnormalities (changes in the lining of the womb) and endometrial
biopsies.
- More on letrozole
-- bone fractures
-- elevation of cholesterol, though this was usually mild.
Heart attacks and strokes slightly more often, though these events
were very rare with both treatmentsEarly breast cancer is defined as cancer that is localized to breast tissue and/or nearby lymph nodes. Worldwide, about 800,000 women are diagnosed with early breast cancer every year. Primary therapy for early breast cancer usually involves surgery to remove the tumor and surrounding tissue. Standard post-surgery therapy (early adjuvant) typically includes radiation and/or chemotherapy, followed by treatment with five years of tamoxifen, previously the "gold standard of care" for postmenopausal women.
BIG 1-98 is being conducted under the umbrella of the Breast International Group, coordinated and managed by the International Breast Cancer Study Group (IBCSG). Novartis, the producer and distributer of letrozole (Femara(R)) gave financial support. The IBCSG is an active member of the BIG organization.
About The International Breast Cancer Study Group
The International Breast Cancer Study Group (IBCSG) is a non-profit organization founded as the 'Ludwig Breast Cancer Study Group' in 1977, which has always been dedicated to innovative clinical research designed to improve the outcome of women with breast cancer. The IBCSG is headquartered in Bern as a foundation under Swiss law. The Statistical and Data Management Centers are in the United States (Boston, MA and Amherst, NY), and the central pathology review offices are in Milan, Italy and Glasgow, Scotland.
About the Breast International Group
The Breast International Group is an international non-profit organization dedicated to serve as a network for large breast cancer trials among its members. The participants are well established clinical research and cooperative groups based in Europe, Australia, New Zealand, South Africa, and Canada, with affiliated centers around the world.
Additional information regarding BIG 1-98 and IBCSG can be found on the website http://www.ibcsg.org.
Contact persons:
PD Dr. Beat Thurlimann, BIG 1-98 Study Chair, Senologie-Zentrum
Ostschweiz, Rorschacherstrasse 95, 9007 St. Gallen. Phone:
+41-71-494-11-78, email: beat.thuerlimann@kssg.ch
Dr. Nadia Munarini, IBCSG Head of Communication, Effingerstrasse 40, 3008
Bern. Phone: +41-31-389-92-27, email: nadia.munarini@ibcsg.org.Web Site: http://www.ibcsg.org
Contact:
Nadia Munarini, PhD, IBCSG, +41-31-389-92-27, or
nadia.munarini@ibcsg.org; PD Dr. Beat Thurlimann, BIG 1-98 Study
Chair, +41-71-494-11-78, or beat.thuerlimann@kssg.ch