The Abramson Cancer Center of the University of Pennsylvania
Ultima Vez Modificado: 1 de noviembre del 2001
(Philadelphia, PA) Approximately 180,000 men will be diagnosed with prostate cancer this year, according to the American Cancer Society. To help decrease these alarming numbers, researchers at the University of Pennsylvania Cancer Center are offering men who may be at an increased risk an opportunity to join one of two new prevention trials. Enrolled participants take a simple, trace element -- selenium-- to determine whether the substance offers protection from the development or advancement of prostate cancer.
Selenium, a natural mineral found in multivitamins and in many foods such as grains, corn, fish, and animal organ meats, was originally investigated as a potential method of preventing skin cancer, but scientists found overwhelming evidence that it reduced prostate cancer risk. "Based on previous studies, there is a strong indication that selenium produces antioxidant affects that have shown to decrease the risk of prostate cancer," says S. Bruce Malkowicz, MD, associate professor of urology and principal investigator on the study. "To confirm these initial findings, we are conducting a long-term comprehensive study assessing the benefits of taking regular doses of selenium and determining whether this substance proves to reduce the incidence of the disease," he explains.
Penn is one of only 12 centers around the country offering these selenium trials, which are funded by the National Cancer Institute. "What makes taking selenium so appealing is that it's considered a natural mineral, one found in many common foods, and when taken in regulated dosages, is completely non-toxic," he explains.
The two trials, categorized as -- 'negative biopsy' and 'watchful waiting' -- are designed to determine if selenium has any effect on the development or growth of the disease.
To be eligible for participation in the negative biopsy trial, men must be in overall good health, have a prostate-specific antigen or (PSA) reading of four or greater, and have had a negative prostate biopsy -- which indicates no evidence of cancer. Participants are randomized to take either a placebo or one of two selenium dosages of 200 or 400 mcg per day, respectively. The participants are monitored every six months and blood tests are taken to measure PSA levels. "We're hoping that this trial will show that selenium significantly decreases the risk of prostate cancer," explains Dr. Malkowicz.
For some men, prostate cancer can be a slowing-growing disease and patients opt for watchful waiting, a method that involves nothing more than periodic surveillance of the cancer growth. For these men, another randomized trial is offered to assess if treatment with selenium slows the advancement of the disease. Participants in this 'watchful waiting' chemoprevention trial are given the substance in one of four different dosages or placebo. Participants may be eligible for this trial if their prostate cancer has been diagnosed within the last 48 months and only if they have not received any standard cancer treatment, such as hormonal therapy, chemotherapy or radiation therapy. "Offering selenium to patients who have already been diagnosed with prostate cancer is like taking a holistic approach towards their disease. For many men, it's a nice option." Malkowicz says.
Prostate cancer is most often diagnosed in men over the age of 50 and it's twice as common among African-American men as among white American men. At the age of 50, the American Cancer Society recommends that all men receive a PSA test and a digital rectal exam to test for the disease.
Men who interested in enrolling in either of these trials can contact Barbara Zoltick, RN, MSN at 215-662-6791.