PROSTATE CANCER: IMPORTANCE OF EARLY DIAGNOSIS
Scientists are working hard to identify the cancer in younger men while it is still confined to the prostate. It is no trivial issue. This year doctors will find 317,000 cases of prostate cancer in the United States, and 41,000 will die of it. The only cancer that kills more American men is lung cancer.
“We are diagnosing the disease much earlier than before,” said Dr. Patrick Craig Walsh, urology chairman at the Johns Hopkins Medical Center in Baltimore and author of The Prostate: A Guide for Men and the Women Who Love Them. “Up ’til 10 years ago,” Dr. Walsh says, “we could detect it only by feeling the gland.” His reference is to the digital rectal examination (DRE), in which a doctor inserts a gloved and lubricated finger through the patient’s rectum to feel the prostate gland. If the prostate seems enlarged, hard, or bumpy, the DRE usually is followed by a biopsy, a microscopic examination of a tissue sample.
“Now,” says Dr. Walsh, “we also have a blood test that alerts doctors to cases that are suspicious. To follow them up, we do a simple biopsy to rule out or identify the cancer. And if it is cancer and it has not spread, then we cut it out.”
That blood test measures prostate-specific antigen (PSA), a chemical produced in the prostate gland. If cancer attacks the gland, the antigen is emitted in large amounts. A high level of PSA in such a test alerts doctors to the chance that the cancer might be growing.
Dr. Joseph E. Oesterling, formerly of the Mayo Clinic in Rochester, Minnesota, and now chief urologist at the University of Michigan Medical Center in Ann Arbor, helped develop a new test with two Scandinavian doctors. It showed that PSA exists in the blood in two forms: free, or attached to a protein molecule. If the prostate is enlarged but not cancerous, more of the free PSA is found; if cancer is present, more of the attached form is found. Dr. Oesterling recommends a yearly blood test for PSA, because a rapid rise in its level can indicate cancer growth.
Testing for PSA has doctors at odds. Some complain that the tests don’t find early cancer but do trigger a sequence of expensive medical steps without prolonging lives. Others urge watchful waiting for aging patients, to spare them the risks and trauma of major surgery.
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