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The study of tamoxifen and raloxifene: preliminary enrollment data from a randomized breast cancer risk reduction
Victor G Vogel1, Joseph P Costantino, D Lawrence Wickerham
1The National Surgical Adjuvant Breast and Bowel Project, NSABP Foundation Inc, Pittsburgh, PA, USA. vvogel@mail.magee.edu
Abstract:
Tamoxifen reduced the risk of invasive breast cancer by 49% among women at increased risk for breast cancer in the Breast Cancer Prevention Trial P-1, and raloxifene reduced breast cancer incidence by more than 70% in the Multiple Outcomes of Raloxifene Evaluation osteoporosis trial. These findings led the National Surgical Adjuvant Breast and Bowel Project to design and launch the Study of Tamoxifen and Raloxifene. Risk-eligible women are = 35 years of age and postmenopausal; they have either lobular carcinoma in situ (LCIS) or a 5-year risk of invasive breast cancer of at least 1.67% as determined by the Gail model. Participants are randomly assigned to receive either tamoxifen 20 mg or raloxifene 60 mg daily. The trial opened for accrual on July 1, 1999. After 32 months of recruitment at 194 clinical centers in North America, risk assessments have been performed in 107,855 women (83.8% white, 9.4% black, 3.8% Hispanic, 3.1% other race/ethnic groups). Of the eligible patients, 12,637 have been randomized (20.9% of risk-eligible women); the median age is 58 years (mean, 58 years), and the median 5-year risk of breast cancer is 3.3% (mean, 4.0%). LCIS was reported in 8.4% of women prior to randomization. Gail model risk was = 3.0% in 5 years for 59.3% of white women, 45.0% of black women, and 44.5% of Hispanic women. The trial will recruit a total of 22,000 postmenopausal women and is powered to demonstrate superior efficacy of either agent or their equivalence in reducing the incidence of primary breast
Insights
Tamoxifen and raloxifene are being studied for breast cancer prevention in postmenopausal women. The Study of Tamoxifen and Raloxifene trial compares these drugs to reduce invasive breast cancer risk.
Area of Science:
- Oncology
- Pharmacology
- Clinical Trials
Background:
- Tamoxifen and raloxifene have demonstrated efficacy in reducing breast cancer risk in prior studies.
- These findings prompted the design of the Study of Tamoxifen and Raloxifene (STAR) trial.
- The STAR trial aims to compare the effectiveness of tamoxifen and raloxifene for breast cancer prevention.
Purpose of the Study:
- To compare the efficacy of tamoxifen and raloxifene in reducing the incidence of primary invasive breast cancer.
- To evaluate the equivalence or superiority of tamoxifen versus raloxifene in a high-risk postmenopausal population.
Main Methods:
- The Study of Tamoxifen and Raloxifene is a randomized clinical trial.
- Participants are postmenopausal women aged 35 years or older with increased breast cancer risk (defined by Gail model or history of lobular carcinoma in situ).
- Women are randomly assigned to receive either tamoxifen 20 mg or raloxifene 60 mg daily.
Main Results:
- Recruitment is ongoing, with over 107,000 women assessed for risk and over 12,600 randomized.
- The median age of randomized participants is 58 years, with a median 5-year breast cancer risk of 3.3%.
- Risk assessment indicates disparities in 5-year risk across different racial/ethnic groups.
Conclusions:
- The trial is powered to detect differences or equivalence in breast cancer incidence between tamoxifen and raloxifene.
- Results will inform clinical decisions regarding breast cancer chemoprevention in high-risk postmenopausal women.
