The firm's studies of more than 6,300 men showed that PSA testing when combined with a rectal exam was more effective in detecting prostate cancer than either a rectal test or PSA test alone. While high levels of PSA may signal prostate cancer, they may also signal other common, non-cancerous prostate disorders. Conversely, low PSA levels do not necessarily indicate an absence of prostate cancer. Therefore, it is important that the PSA test be interpreted with results from other established procedures such as a digital rectal exam. If either test is positive, confirmatory testing with transrectal ultrasound and biopsy is needed to diagnose prostate cancer.
Prostate cancer is the second most common cancer in men in the United States, after skin cancer.
The prostate gland, which produces seminal fluid, is about the size of a walnut and is located below the bladder and in front of the rectum. Most cases of prostate cancer occur in men 65 or older, with the risk increasing with age. Approximately 13 percent of American men will be diagnosed with the disease during their lifetimes, but most cases never become life threatening. Many questions still remain in the medical community about how best to treat prostate cancer. To help answer these and other questions, the National Cancer Institute is currently sponsoring a long-term screening study of 37,000 men, ages 60 to 74.