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July 13, 1999
News this month
STAR trial focuses on breast cancer prevention
The Study of Tamoxifen and Raloxifene, or STAR, is one of the largest breast cancer prevention studies ever organized. Women from the U.S., Puerto Rico and Canada are now being accepted into the trial, which will last about five years. The study will compare whether the osteoporosis prevention drug raloxifene (Evista ®) is as effective in reducing the chance of developing breast cancer as tamoxifen (Nolvadex ®) has proven to be. In all, about 22,000 postmenopausal women at increased risk of breast cancer are expected to participate.
Researchers organized the STAR trial to see if raloxifene is as effective as tamoxifen, and any side effects raloxifene may have.
The role of hormone therapy
Scientists now know that certain hormones, such as testosterone in men and estrogen in women, stimulate the growth of certain cancer cells. Testosterone prompts the growth of prostate cancer cells in men, while estrogen stimulates breast cancer cells. Attention has focused on developing drugs that stop cancer cells from using these hormones. For example, tamoxifen works by stopping breast cancer cells from using estrogen. But because tamoxifen increases the risk of developing endometrial cancer and blood clots, researchers organized the STAR trial to see if raloxifene is as effective as tamoxifen, and any side effects raloxifene may have.
Who can participate?
To participate in the STAR trial, women must:
- Be at least 35 years old
- Have had a mammogram in the past 12 months with no evidence of cancer
- Not have had a mastectomy to prevent breast cancer
- Have completed menopause or had a hysterectomy
- Have no history of invasive breast cancer or intraductal carcinoma in situ (localized cancer that has not spread).
- Not have taken hormone therapy in at least three months.
Determining breast cancer risk
Participants must also be considered at increased risk. A computer will calculate whether they at greater risk based on:
- Current age
- Number of relatives (mother, daughters, or sisters) diagnosed with breast cancer
- Race
- If a woman had any children, and age at first delivery
- The number of breast biopsies a woman has had, especially if the tissue showed a condition known as atypical hyperplasia
- Age at first menstrual period
Groups to receive tamoxifen or raloxifene
A woman can use the computer-generated profile to decide whether she wants to participate. Once accepted into the trial, women are randomly placed in one of the two groups. In one group, women will take by mouth raloxifene plus a placebo (tamoxifen look-alike) once a day, and in the other group, women will receive tamoxifen plus a placebo (raloxifene look-alike) by mouth once a day also. Neither the researchers nor the women will know who is getting tamoxifen and who is getting raloxifene until the end of the trial. This type of trial, called a double-blinded study, is necessary so the results are not influenced in any way.
Participants will be evaluated at the beginning of the study, every three to six months during the first year, then every six months during the next four years. After five years, they will receive a follow-up evaluation.
Study Sponsors
This study is being conducted by researchers with the National Surgical Adjuvant Breast and Bowel Project (NSABP) and will be conducted at more than 400 centers in the U.S., Puerto Rico and Canada. It is primarily funded by the National Cancer Institute, the U.S. government's main agency for cancer research.
Interested in finding out more about the STAR Trial?
Call Barbara Siconolfi, RN, toll-free 1-877-614-STAR (7827) or (203) 737-5908. Outside of Connecticut, go to the STAR contact list (an Acrobat PDF file) to find the participating center closest to you.
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The importance of the STAR trial
In recent years, researchers have begun to study drugs that, for the first time, prevent breast cancer. In 1998, results of the Breast Cancer Prevention Trial were published. This study gave the world its first hope that a drug called tamoxifen could be used to prevent breast cancer in high-risk women. Researchers found a stunning 49 percent decline in the incidence of invasive breast cancer in women compared to those who did not take the drug. Before this trial, tamoxifen had been used for 20 years as a treatment for women with breast cancer.
“Raloxifene also appears to lower rates of breast cancer.”
Weighing tamoxifen's risks
Taking tamoxifen carries some risks, however, including an increased risk of endometrial (uterine) cancer and increased risk of blood clots and possibly stroke. When my patients consider taking tamoxifen, they weigh these risks against the risk of breast cancer. Because of these side effects, my colleagues and I have hoped for a drug that would lower breast cancer rates without the side effects.
Raloxifene was approved in 1997 by the U.S. Food and Drug Administration to prevent osteoporosis in post-menopausal women. Raloxifene is an interesting drug. In recent studies, it acted much like estrogen in its ability to increase bone mineral density and lower blood levels of total and low-density lipoprotein cholesterol, without stimulating the endometrium, the lining of the uterus.
Raloxifene connected with reduced breast cancer
Raloxifene also appears to lower rates of breast cancer. Women who took the drug for osteoporosis had overall lower rates of breast cancer than women who did not, although the participants were not necessarily at increased risk for breast cancer. The STAR trial should provide more information about raloxifene's protective nature and any side effects.
“Deciding to participate is a decision that must be made only after careful consideration.”
Raloxifene is similar to tamoxifen. They are both SERMS, short for selective estrogen receptor modifiers. This means they make it harder for a cancer cell to use estrogen produced by a woman's body. That's important because estrogen can fuel the growth of breast cancer cells.
STAR trial the next step
The STAR trial is one of the largest breast cancer prevention trials ever organized. In such a trial, participants who meet certain criteria agree to take medications as prescribed for a certain amount of time, in this case either tamoxifen or raloxifene, for five years. During this time, they are closely monitored to see if the drugs are helping. An attractive feature of this trial is that women in both groups will be receiving active agents.
Things to consider before participating in a study
Women interested in participating in the STAR trial will be fully informed of the benefits and potential risks of these drugs. The most common side effects of either drug are hot flashes and vaginal discharge and often treatments can reduce these side effects.
Deciding to participate is a decision that must be made only after careful consideration. People participate in cancer prevention clinical trials for many reasons. They may be at high risk for cancer and want to take a more active role in their health care. Because they will be closely supervised during the trial, some health problems may be found early. Others experience a sense of satisfaction knowing they are contributing to medical knowledge. If the study agent turns out to be effective against cancer, it may help others.
Participants must be informed of the drawbacks. New approaches may have side effects or risks unknown to the doctors. The side effects or results may be worse than expected or the benefits may not work for you. There also may be costs associated with a clinical trial.
Questions to ask about clinical trials
Make sure you know why the study is being done, how long it will last, who is sponsoring the study and how the safety of participants is being checked. You should also ask what you will need to do to participate (such as come for medical exams, take certain medications, etc) and who will provide the care. Can you continue to take regular medications? Will you ever find out what you took? Are there any costs involved in participating?
Benefits vs. risks
When deciding whether to participate, also ask:
- What are the short-term benefits for me?
- What are the long-term benefits for me?
- Are there any short-term or long-term risks or side effects?
- Is there any other way to prevent this type of cancer?
- How do the risks of this trial compare with those options?
The women who, after careful thought, decide to participate will make a lasting contribution to the efforts to prevent breast cancer.
Dr. Barbara Ward is the principal investigator of the STAR Trial at the Yale Cancer Center, director of the Yale Comprehensive Breast Care Center and is a surgical oncologist affiliated with Yale-New Haven Hospital.
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