
Breast Cancer Prevention Trials:
The NSABP P1 Trial
Trial objective: To determine whether tamoxifen administered for 5 years prevented invasive breast cancer in women at increased risk of the disease.1
P1 study design: Patients were randomized to receive either placebo (6,707) or tamoxifen 20 mg/day (6,681) for 5 years.1
P1 patient population: 13,388 women at increased risk for breast cancer because they met one of the following criteria1:
- Age 60 years or older, or
- Age 35-59 years and had a 5-year predicted risk for breast cancer of at least 1.66% based on the Gail model, or
- Had a history of lobular carcinoma in situ (LCIS)
Results: Tamoxifen reduced the risk of invasive breast cancer over 5 years in women at increased risk.1

The NSABP P2 (STAR) Trial
Trial objective: To compare the relative effects and safety of EVISTA and tamoxifen on the risk of developing invasive breast cancer and other disease outcomes.2
P2 (STAR) study design: 19,747 patients were randomized to receive either tamoxifen 20 mg/day (9,726) or EVISTA 60 mg/day (9,745) for a maximum of 5 years.2
- All were postmenopausal women age 35 and older
- All participants were at high risk of invasive breast cancer based on the Gail model score (≥1.66%) or had a history of LCIS treated with surgery alone
P2 (STAR) patient characteristics: 91% of participants were age 50 or older.2
- Mean age = 59 years
- Mean Gail score = 4.03% ± 2.17%
A Gail score ≥1.66% is defined as high risk.
Results: The incidence rates of invasive breast cancer were similar (EVISTA 4.4 and tamoxifen 4.3 per 1,000 women per year).

Please refer to prescribing information for tamoxifen.
EVISTA vs tamoxifen in the P2 (STAR) trial2

- Patients with a history of AH at the entry of the trial had similar incidence rates of invasive breast cancer in both treatment groups
- Patients with a history of LCIS at entry of the trial had similar incidence rates of invasive breast cancer in both treatment groups
*The highlighted rows depict areas where the difference between treatment groups was statistically significant.Please refer to prescribing information for tamoxifen.
- J Natl Cancer Inst. 1998;90:1371-1388.
- JAMA. 2006;295:2727-2741.
- Data on file, Lilly Research Laboratories (EVI20070910).
























