Premenopausal women who have been diagnosed with breast cancer have improved survival if their chemotherapy doses are delivered every two weeks, compared to every three weeks. These results were recently presented at the 2016 European Breast Cancer Conference (EBCC-10) in the Netherlands.
Chemotherapy following surgery is a standard treatment option for premenopausal women diagnosed with breast cancer. A standard regimen includes chemotherapy delivered every 3 weeks. The delivery of chemotherapy at closer time intervals, such as every 2 weeks, is referred to as “dose-dense.”
Premenopausal women with breast cancer are unique in several ways when compared to the majority of breast cancer cases, which include postmenopausal women. Breast cancer in premenopausal women tends to be more aggressive than that in postmenopausal women. In addition, treatment may cause ovarian suppression, leading to a type of early menopause. In turn, this early menopause is associated with a reduced quality of life due to side effects such as hot flashes, sweats, breast pain or sensitivity, vaginal dryness, vaginal discharge, lack of sexual desire, and weight gain. Importantly, treatment for breast cancer in premenopausal women may cause infertility, a highly emotional issue for many patients.
Different therapeutic strategies for premenopausal women with breast cancer continue to be explored to determine which treatments can achieve optimal survival rates, while minimizing associated side effects.
Researchers from Europe recently conducted a meta-analysis from two large phase III clinical trials comparing dose-dense chemotherapy (every 2 weeks) to standard delivery of chemotherapy (every 3 weeks) to treat premenopausal women with breast cancer.
The two trials, referred to as the MIGI and GIM2 studies included 3,305 premenopausal patients with breast cancer that had spread to their lymph nodes, or who were otherwise at a high risk of developing a cancer recurrence. The average patient age was 44 years.
- Overall survival was improved by nearly 30% among the women treated with dose-dense chemotherapy compared to those treated with standard-dose chemotherapy.
- At 10 years, survival for women with hormone-negative breast cancer (cancer that is not stimulated to grow from exposure to female hormones) was improved by 35% among those treated with dose-dense chemotherapy, compared to those treated with standard-dose chemotherapy.
- At 10 years, survival for women with hormone-positive breast cancer (cancer that is stimulated to grow from exposure to female hormones) had a 22% increase in survival if treated with dose-dense chemotherapy versus standard-dose chemotherapy.
- Importantly, dose-dense chemotherapy was not associated with an increased risk of developing amenorrhea (early menopause) from treatment.
- The development of amenorrhea was not significantly associated with improved survival; however, there was a trend of increased survival among women with hormone-positive breast cancer and the development of amenorrhea.
Professor Fatima Cardoso, Director of the Breast Unit at the Champalimaud Clinical Centre in Lisbon, Portugal, and Chair at EBCC-10, said: “This meta-analysis provides important information that has the potential to change and improve the treatment of breast cancer in premenopausal patients. It gives us evidence-based answers as to whether or not dose-dense chemotherapy can be used in these patients without increasing their risks of treatment-induced amenorrhea, as well as showing a survival benefit.”
Reference: Lambertini M, et al. Dose-dense adjuvant chemotherapy, treatment-induced amenorrhea and overall survival in premenopausal breast cancer patients: a pooled analysis of the MIG1 and GIM2 phase III studies. Oral Abstract session at the 10th annual European Breast Cancer Conference. 2016; Abstract 5. Available at: http://www.ecco-org.eu/Global/News/EBCC/EBCC10-PR/2016/03/Chemotherapy-every-2-weeks-for-premenopausal-breast-cancer-patients-improves-survival. Accessed March 15, 2016.
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