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NCI DCP News Note

STAR Enrollment Statistics

Updated: 02/02/2011   The Study of Tamoxifen and Raloxifene (STAR) is a breast cancer prevention clinical trial designed to determine whether the osteoporosis prevention drug raloxifene (Evista®) is as effective as tamoxifen (Nolvadex®) in reducing breast cancer risk, with fewer side effects. The trial began enrolling participants in July 1999 and completed enrollment in November 2004 with 19,747 postmenopausal women at increased risk of breast cancer.

STAR Enrollment Data: Overview

  • For STAR, 184,461 women went through the risk assessment process to determine their eligibility for the trial. Of these women, 96,368 were eligible for the trial because of their increased risk of developing breast cancer. Of those risk-eligible women, 19,747 chose to participate.
  • Of the 19,747 women who joined STAR, 1,344 were from the placebo group of the Breast Cancer Prevention Trial (the study that compared tamoxifen to a placebo).
  • The estimated breast cancer risk of women in STAR was substantially above the required minimum 1.66 percent risk of developing the disease within the next five years.
Five Year Breast Cancer RiskWomen in STAR Who Fell Into This Risk Category
1.66 - 1.99%11.0% (2,176)
2.0 - 2.99%30.2% (5,962)
3.0 - 4.99%31.5% (6,229)
Greater than 5.0%27.2% (5,380)

  • Women joining STAR had to have been postmenopausal and at least 35 years of age. The ages of women joining STAR:
Age RangeWomen in STAR Who Fell Into This Age Range
35-499.2% (1,815)
50-5949.7% (9,821)
60+41.1% (8,111)

  • 9.1 percent (1,792) of the women who joined STAR reported a previous diagnosis of lobular carcinoma in situ (LCIS), a condition that is not cancer, but which indicates an increased chance of developing invasive breast cancer.

  • About half of the women who joined STAR had had a hysterectomy prior to enrolling (51.7 percent). Women who have had a hysterectomy are not at risk for endometrial cancer; tamoxifen can raise a woman's chance of developing that disease.

  • The majority of women on STAR (71.2 percent) reported at least one close relative with breast cancer.

  • Postmenopausal women of all races and ethnic backgrounds were encouraged to participate in STAR, and more than 6 percent of the women in STAR were from minority groups. A total of 38,910 women from minority groups went through the risk assessment process; 8,359 had an increased risk of breast cancer that would qualify them for the study; and 1,301 joined the trial.

  • Among African-American participants, 21,444 went through the risk assessment process, 3,280 were risk-eligible, and 488 joined STAR. About 2.5 percent of STAR participants were African-American.

  • Among Hispanic/Latina women, 7,913 went through the risk assessment process, 1,841 were risk-eligible, and 394 joined STAR. About 2.0 percent of the women on STAR were Hispanic/Latina.

  • Among women who defined themselves as representing another minority population, such as Native American or Asian American, 9,553 have gone through the risk assessment process, 3,238 were rick-eligible, and 419 joined STAR. About 2.1 percent of the women on STAR were ethnic minorities other than African-American or Hispanic/Latina.

  • For comparison, the Breast Cancer Prevention Trial - the predecessor study to STAR - had a total of 8,525 minority women go through the risk assessment process, 2,979 were risk-eligible, and 486 joined this 13,000-woman trial (about 4 percent of participants).

STAR Enrollment Data: By State and Province

Here is a table of enrollment data categorized by U.S. state (including Puerto Rico and the District of Columbia) and Canadian province.

STAR enrollment

State or Province, alphabetically by postal codeNumber of STAR participantsState or Province, alphabetically by postal codeNumber of STAR participants
AR-Arkansas70NC-North Carolina915
AZ-Arizona199ND-North Dakota82
BC-British Columbia112NE-Nebraska208
CA-California1,369NH-New Hampshire40
CO-Colorado349NJ-New Jersey95
CT-Connecticut307NM-New Mexico87
DC-District of Columbia64NV-Nevada99
DE-Delaware149NY-New York808
IN-Indiana222PR-Puerto Rico76
KS-Kansas337SC-South Carolina343
KY-Kentucky199SD-South Dakota161
MO-Missouri795WV-West Virginia68

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