July 24, 2001
Media Relations, LHSC
519-685-8500, ext. 77642
London Health Sciences Centre and London Regional Cancer Centre Begin Enrolling Men Today in Largest-Ever Prostate Cancer Prevention Trial Vitamin E and Selenium to be Tested as Prevention Agents
(LONDON, Ontario) - Healthy men age 55 and older are needed for the largest-ever prostate cancer prevention study, launched today by the National Cancer Institute (NCI), London Health Sciences Centre and London Regional Cancer Centre which are part of a network of research sites known as the Southwest Oncology Group (SWOG). The Selenium and Vitamin E Cancer Prevention Trial, or SELECT, seeks to learn if these two dietary supplements can protect against prostate cancer, the most common form of cancer, after skin cancer, in men.
More than 400 sites in the United States, Puerto Rico, and Canada are recruiting participants for SELECT, which will take up to 12 years to complete. The study will include a total of 32,400 men.
“SELECT is the first study designed to look directly at the effects of vitamin E and selenium, both separately and together, in preventing prostate cancer,” say principal investigators Dr. Eric Winquist and Dr. Joseph Chin. “Previous research involving vitamin E and selenium suggested that these nutrients might prevent prostate cancer, but we don’t know for sure. When SELECT is finished we will know whether these supplements can prevent prostate cancer.”
During this year alone, prostate cancer will be diagnosed in about 198,100 Americans and more than 31,500 men are expected to die of the disease. In Canada, approximately 16,800 new cases of prostate cancer will be diagnosed this year and about 4,200 men will die of it. Risk factors for the disease include being over age 55, being black, or having a father or brother with prostate cancer.
“It is crucial that men of all races and ethnic backgrounds participate in SELECT,” said Leslie Ford, M.D., associate director for clinical research in NCI’s Division of Cancer Prevention. “And since African-American men have the highest incidence of prostate cancer in the world, we especially encourage them to consider joining this trial.” The disease also strikes black men at a younger age, so they will be eligible to enroll in the study at age 50, vs. age 55 for other racial and ethnic groups. There is no upper age limit for participation in SELECT.
“We are looking for quite a few good men to join SELECT,” said Charles A. Coltman, Jr., M.D., chairman of SWOG and director of the San Antonio Cancer Institute in San Antonio, Texas. “This study is important for the men who join, not only because they might prevent prostate cancer for themselves, but also because what we learn has the potential to benefit future generations of men.”
Selenium and vitamin E, both naturally occurring nutrients, are antioxidants. They are capable of neutralizing toxins known as “free radicals” that might otherwise damage the genetic material of cells and possibly lead to cancer. These nutrients were chosen for study because of the results of two other large cancer prevention trials.
In a study of selenium to prevent one type of nonmelanoma skin cancer in 1,000 men and women, reported in 1996*, investigators found that while the supplement did not reduce skin cancer, it did decrease the incidence of prostate cancer in men by more than 60 percent.
Another trial, published in 1998**, in which beta carotene and vitamin E were tested to prevent lung cancer in 29,000 Finnish men who smoked, those who took vitamin E had 32 percent less prostate cancer. Neither beta carotene nor vitamin E prevented lung cancer. In fact, the men who smoked and took beta carotene were more apt to get lung cancer and die from it than men who didn’t take this supplement.
“SELECT is the critical next step for pursuing the promising leads we saw for the prevention of prostate cancer,” said Ford, who is responsible for all aspects of NCI’s involvement in SELECT. “The only way to determine the real value of these supplements for prostate cancer is to do a large clinical trial focused specifically on this disease.” Study investigators hope to recruit all the study participants during the first five years of the trial, so that each man can be followed for at least seven years.
Men in the study from Southwestern Ontario will visit LHSC/LRCC once every six months. Upon enrollment, they will be assigned by chance to one of four groups. One group will take 200 micrograms of selenium daily plus an inactive capsule, or placebo, that looks like vitamin E. Another group will take 400 milligrams of vitamin E daily along with a placebo that looks like selenium. A third group will take both selenium and vitamin E. And a final group will be given two placebos.
Men who join SELECT will not need to change their diet in any way, but they must stop taking any supplements they buy themselves that contain selenium or vitamin E. If participants wish to take a multivitamin, SWOG will provide, without charge, a specially formulated one that does not contain selenium or vitamin E.
Men may be able to participate in SELECT if they:
- are age 55 or older; age 50 or older for black men
- have never had prostate cancer and have not had any other cancer, except nonmelanoma skin cancer, in the last five years
- are generally in good health
Men interested in joining the study can call The SELECT Research Office at (519) 685-8261. For more information about the study or prostate cancer:
- In the United States (including Puerto Rico), call the National Cancer Institute’s Cancer Information Service at 1-800-4-CANCER (1-800-422-6237) for information in English or Spanish. The number for callers with TTY equipment is 1-800-332-8615.
- In Canada, call the Canadian Cancer Society’s Cancer Information Service at 1-888-939-3333 for information in English or French.
- Visit NCI’s Web site at http://cancer.gov/select or visit SWOG’s Web site at http://swog.org and choose SELECT.
Four pharmaceutical companies are providing selenium and vitamin E capsules and multivitamins for the study: Roche Vitamins Inc., Parsipanny, N.J.; Sabinsa Corporation, Piscataway, N.J.; Nutricia Manufacturing USA Inc., Greenville, S.C.; and BioAdvantex Pharma Inc., Mississauga, Ontario, Canada.
To find out more about the SELECT study at LHSC/LRCC or to arrange an interview with Dr. Winquist or Dr. Chin, members of the media may call Nancy Lawrence, Media Relations & Communications, London Health Sciences Centre, (519) 685-8500, ext. 77642.
* Clark LC, Combs GF Jr, Turnbull BW, et al. Effects of selenium supplementation for cancer prevention in patients with carcinoma of the skin. A randomized controlled trial. Nutritional Prevention of Cancer Study Group. JAMA 276:1957-1963, 1996.
** Heinonen OP, Albanes D, Huttunen JK, et al. Prostate cancer and supplementation with alpha-tocopherol and beta-carotene: incidence and mortality in a controlled trial. J Natl Cancer Inst 90:440-6, 1998.
Questions and Answers: SELECT (Selenium and Vitamin E Cancer Prevention Trial)
- What is SELECT?
SELECT stands for the Selenium and Vitamin E Cancer Prevention Trial, which is a clinical trial to see if one or both of these dietary supplements prevent prostate cancer in men. It is funded by the National Cancer Institute (NCI) and is being coordinated by the Southwest Oncology Group (SWOG), an international network of research institutions that receives NCI funding. Enrollment will last for approximately five years, and each man’s participation will last seven to 12 years. More than 400 sites in the United States, Puerto Rico, and Canada are taking part in the study. Over 32,000 men will participate in SELECT.
- What are a man’s chances of developing prostate cancer?
After skin cancer, prostate cancer is the most common type of cancer in men in the United States. There will be an estimated 198,100 new cases of prostate cancer and 31,500 deaths from this disease in the United States in the year 2001.
All men are at risk, but those at highest risk fall into one or more of the following categories: age 55 or older; black; or have a father or brother with prostate cancer.
- What is selenium? Why study it for prostate cancer prevention?
Our bodies need selenium, a nonmetallic trace element that we get from water and food -- especially seafood, meats and Brazil nuts. Selenium is an antioxidant that is believed to help control cell damage that can lead to cancer.
In a 1996 study of 1,000 men and women, those men who took selenium to prevent nonmelanoma skin cancer found no benefit from selenium in preventing skin cancer. However, there were more than 60 percent fewer new cases of prostate cancer in those men taking selenium than in those men who did not, which is one of the reasons why this substance is being studied in SELECT.
- What is vitamin E? Why study it for prostate cancer prevention?
We get vitamin E, a naturally occurring nutrient, in a wide range of foods, especially vegetables, vegetable oils, nuts and egg yolks. Vitamin E, like selenium, is an antioxidant that is believed to help control cell damage that can lead to cancer.
In a 1998 study of 29,000 male smokers in Finland, men who took vitamin E to prevent lung cancer had 32 percent fewer new cases of prostate cancer than men who took the placebo. Some men also took beta carotene, but neither substance helped prevent lung cancer.
- What do researchers hope to learn from SELECT?
SELECT is the first study to look directly at the effects of selenium and vitamin E on the risk of prostate cancer. This study is being done to find out if selenium, vitamin E, or both, prevent prostate cancer.
A large trial of selenium and vitamin E is needed to substantiate earlier, separate findings where prostate cancer was not the primary outcome. Although two earlier studies suggested that these two supplements may prevent prostate cancer, this cancer was not the focus of those studies. The primary goal of SELECT is to assess the effect of these substances on the number of new cases of prostate cancer diagnosed during routine clinical practice. Other objectives are to assess the impact of selenium and vitamin E on the incidence of lung and colon cancer, as well as on survival. SELECT will study molecular and genetic markers of cancer risk and associations between diet and cancer. Additionally, SELECT will also examine quality of life.
- Who is eligible to participate in SELECT?
Black men must be age 50 or older to participate, and men of other races and ethnicities must be 55 or older. The age for eligibility is lower for black men because they get the disease at an earlier age. In addition, black men in the United States have the highest incidence of prostate cancer in the world.
Participants must have no prior history of prostate cancer. Men who join SELECT also must not have had any other cancer, except non-melanoma skin cancer, in the last five years. They must be in generally good health. In addition, many of the 18,000 men who enrolled in another prevention study sponsored by NCI and run by SWOG, known as the Prostate Cancer Prevention Trial (PCPT), will be eligible to participate in SELECT once they have completed the PCPT by having had their end-of-study biopsy and exited the PCPT trial with no evidence of prostate cancer.
Many diseases, including prostate cancer, occur more frequently in older persons. The risk of developing prostate cancer increases with age. About 98 percent of prostate cancer cases occur in men ages 55 and older. Thus, the SELECT age requirement ensures that men who are at risk for the disease are targeted.
- Can men with benign prostatic hyperplasia (BPH) join SELECT?
Men with BPH, an abnormal growth of benign prostate cells, can join SELECT because BPH is not a cancerous condition. In BPH, the prostate grows larger and presses against the urethra and bladder, interfering with the normal flow of urine. More than half of the men in the United States between the ages of 60 and 70 and as many as 90 percent of men between the ages of 70 and 90 have symptoms of BPH.
- What tests are used to determine eligibility for SELECT?
Tests include a digital rectal examination (DRE) and a prostate-specific antigen (PSA) test. During a DRE, a doctor inserts a gloved finger into the rectum and feels the prostate gland through the rectal wall to check for bumps or abnormal areas. The PSA test measures the level of PSA (a protein produced by the cells of the prostate gland) in the blood. PSA levels can rise due to cancer or benign (not cancerous) conditions. Doctors often use the PSA test and DRE as prostate cancer screening tests in men who have no symptoms of the disease. To be eligible for the SELECT trial, participants must have a DRE that indicates no signs of prostate cancer and a total PSA level less than or equal to 4.0 ng/ml.
- Who will get which supplement?
Men who participate in this study will take two capsules a day. Participants are randomized to four possible choices:
- selenium and vitamin E
- selenium and a placebo
- vitamin E and a placebo
- two placebos
Neither the participants nor the researchers will know who is receiving the selenium and vitamin E, or the placebos. There are two placebos used in the trial: one looks and tastes like a selenium capsule; the other looks and tastes like a vitamin E capsule. Each placebo contains only inactive ingredients.
Roche Vitamins Inc., Parsipanny, N.J., is donating bulk vitamin E and vitamin E placebo; Nutricia Manufacturing USA Inc., Greenville, S.C., is encapsulating the vitamin E and vitamin E placebo at no charge; and Sabinsa Coporation, Piscataway, N.J., is providing selenium and selenium placebo, both of which are already encapsulated, at manufacturing cost.
- How much selenium and vitamin E are being studied? What risks might be involved?
The amount of selenium and vitamin E used in SELECT is 200 micrograms (µg) of selenium and 400 milligrams (mg), which is equivalent to 400 International Units (IU), of vitamin E per day. Previous studies have shown that these amounts are safe in healthy men.
The 200 µg per day dose of selenium would have to be increased to more than 2,400 µg per day of selenium for it to be considered “too much.” The 400 mg dose of vitamin E is safe, but can thin blood somewhat. Men with uncontrolled high blood pressure may have an increased risk of stroke if they take 400 mg of vitamin E and therefore can not take part in this study.
- What other requirements are there for SELECT participants?
Participants will be asked to return to the study site every six months for evaluation and to pick up a six month supply of capsules. Researchers conducting the study recommend that participants have an annual DRE examination and a PSA test in accordance with the standard of care at their study site. If prostate cancer is found during one of the visits, the participant will be referred for treatment, will stop taking the study supplements, and will continue to be followed by the SELECT study staff, although with less frequency.
Upon enrollment, men will be asked to have toenail clippings collected to assess selenium levels in the body since selenium concentrates in fingernails and toenails. Toenails are chosen over fingernails because they take longer to grow and thus contain more history of someone’s selenium intake. Blood samples will also be collected upon enrollment to assess levels of vitamin E.
Men will fill out a questionnaire on their diet and past supplement use upon enrolling. There will also be an annual questionnaire that asks for updates of some of this information. Men do not have to change their diets during this study. Each man will be offered a free supply of a special daily multivitamin, manufactured by BioAdvantex Pharma Inc., Mississauga, Ontario, Canada, that contains no selenium or vitamin E, to take as he chooses.
- Why should men participate in SELECT?
Men involved in SELECT will be partners in medical research that may decrease their chances of getting prostate cancer. Information learned from this study may also help future generations of men avoid this cancer.
- What other clinical trials are under way for prostate cancer prevention?
In addition to SELECT and the Prostate Cancer Prevention Trial, smaller trials are also being conducted with a variety of agents, including a vitamin D analog; eflornithine (a compound called DFMO); Flutamide and Casodex (both antiandrogens); soy isoflavones; lycopene (a plant pigment common in tomatoes); celecoxib (a COX-2 inhibitor); and combinations of agents.
- How can a potential participant or a physician get more information about SELECT?
In the United States and Puerto Rico, call the National Cancer Institute’s Cancer Information Service at 1-800-4-CANCER (1-800-422-6237 or TTY: 1-800-332-8615) for information in English or Spanish. In Canada, call the Canadian Cancer Society’s Cancer Information Service at 1-888-939-3333 for information in English or French. The following Web sites can also provide additional information:
- For the SELECT Web site, hosted by SWOG, choose the SELECT option at http://swog.org
- NCI information on SELECT: http://cancer.gov/select
- Information from NCI about prostate cancer, including risk, genetics, statistics, and much more at: http://cancernet.nci.nih.gov/Cancer_Types/Prostate_Cancer.shtml
- For the SELECT Web site, hosted by SWOG, choose the SELECT option at http://swog.org