Breast Cancer Prevention Trial Completes Recruitment: Answers Expected in Two to Three Years

National Cancer InstituteFOR IMMEDIATE RELEASE, Monday, June 23, 1997, Lori Psillidis, NSABP Operations Center, NCI Press Office

After five years, recruitment for the Breast Cancer Prevention Trial (BCPT) ended May 30, 1997, and results are expected in two to three years. The 13,000th woman joined the study on May 20. Women who have qualified to participate, but who have not completed pre-entry tests and examinations, have until Sept. 1, 1997 to enroll.

"Reaching this milestone is a tremendous accomplishment for the oncology community," said Leslie Ford, M.D., associate director for early detection and community oncology at the National Cancer Institute (NCI), and NCI coordinator for the study. "Finding a way to prevent breast cancer is one of the most important research questions we have to answer. Each and every woman who has chosen to participate has my gratitude for their trust and conviction in seeing this study through."

Norman Wolmark, M.D., chairman of the Pittsburgh-based National Surgical Adjuvant Breast and Bowel Project (NSABP), the NCI-sponsored research network conducting the BCPT, also thanked and praised the participants. "Reaching this point in the study represents an achievement of unprecedented dimension. Everyone recognizes that breast cancer is a major health problem for women, and the 13,000 women who have entered this trial are doing something positive and productive about it. The contribution they have made in the fight against this disease is immeasurable."

Recruitment for the BCPT, the first large-scale, randomized study to assess whether a five-year course of the breast cancer treatment drug tamoxifen (Nolvadex ) can prevent breast cancer in women at increased risk, began April 29, 1992. Researchers from the NSABP originally estimated that they would need 16,000 participants. Last September, they announced that the participants, on average, had a much greater underlying risk of breast cancer than anticipated, so only 13,000 women would be needed.

To qualify for participation, a woman had to be at least 35 years of age and have a risk of developing breast cancer in the next five years that was 1.7 percent (17 of 1,000 women at this level of risk would be expected to develop breast cancer within five years). Women aged 60 years and older qualified based on age alone, but women 35 to 59 had to have risk factors that increased their risk to this level. On average, the women who volunteered had at least twice that risk.

Breast cancer risk was evaluated based on the following factors: the number of first-degree relatives (mother, daughter, or sisters) who have been diagnosed with breast cancer, whether or not a woman has had any children and her age at her first delivery, the number of times a woman has had breast lumps biopsied (especially if she has a condition known as atypical hyperplasia), her age at her first menstrual period, and if she has a type of noninvasive breast cancer known as lobular carcinoma in situ.

The participants represent each of three age groups about equally: Ages 35 to 49 (premenopausal), ages 50 to 59 (perimenopausal), and age 60 and older (postmenopausal). About 4 percent of the women are from a racial or ethnic minority group (African-American, Hispanic, Asian, or other).

The 13,000 women have been randomized (divided by chance) to take either 20 milligrams of tamoxifen daily or a placebo for five years. All of the participants will take their tamoxifen or placebo for the full five years, unless early beneficial or adverse results are seen. An independent review committee regularly reviews interim results to ensure the safety of the participants. Participants who complete five years of therapy will be followed for at least two more years.

Rici Rutkoff, one of the co-chairs of the BCPT Participant Advisory Board, a group of 16 women who participate in the trial, shares the enthusiasm. "I'm thrilled that we've reached our accrual goal because now we can get down to the business of finding out if tamoxifen will prevent breast cancer," she said. Sandi Kanicki, the other co-chair, feels privileged to be part of the study, adding, "Since joining the trial I have become a real advocate for women's health, which will carry on long after the study is over. My five-year commitment to the study has become a life-long commitment."

BCPT researchers are also conducting smaller studies involving portions of the 13,000 participants to assess the action of tamoxifen on blood lipid levels (such as cholesterol) and bone density. Although tamoxifen is an anti-estrogen, it works against estrogen in some tissues and like estrogen in others. Its actions like estrogen help reduce blood lipids, which may ultimately reduce the number of heart disease deaths that occur, and help retain bone density.

Tamoxifen is one of the most widely prescribed cancer drugs in the world, with more than 20 years of research studying its actions, benefits, and risks. Zeneca Pharmaceuticals, Wilmington, Del., manufactures tamoxifen and provides both the tamoxifen and placebo pills for the study without charge.

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