The traditional rectal exam, for millions of middle-aged and older men the low point in a medical checkup, may fail in its main purpose, the prevention of advanced prostate cancer, a Kaiser-Permanente medical system study says.
The conclusion runs counter to long-held beliefs of physicians.
Most experts still say -- even in the face of the new study and a few previous reviews with similar results -- that the exam is worthwhile because it is quick and simple and poses no risk to patients. More important, many doctors think that the exam occasionally enables them to find cancers in time to treat them successfully.
The lead author of the new paper remains inclined to perform the exam, he said, although the Kaiser system's huge store of medical records and computerized analytic methods has not provided statistics showing the test's value.
He says he would not argue forcefully with patients who do not want it.
"Ever since I was in medical school it was considered a standard thing to do. But when you look at the evidence, it doesn't look so persuasive," said Dr. Gary D. Friedman, director of the Division of Research at the Kaiser Permanente Medical Care program in Oakland, Calif.
The widely respected British medical journal Lancet published in June a report on the study by Friedman and co-authors Dr. Robert A. Hiatt, Charles P. Quesenberry Jr., and Dr. Joseph V. Selby.
Statistics from the American Cancer Society show prostate cancer second only to skin cancer among men, with an estimated 122,000 cases in the United States this year. Its 32,000 deaths annually make it the second-biggest cancer killer among men.
The cancer society recommends the rectal exam every year for men over 40.
During the exam, the doctor uses his or her latex-gloved finger to reach through the patient's rectum to feel for any enlargement or irregularities in the prostate, a gland wrapped around the urethra near the base of the male bladder.
Dr. E. David Crawford, urology chairman at the University of Colorado School of Medicine, said the test, particularly in combination with newer methods -- including detection of distinctive chemical antigens in the blood that can signal prostate cancer and an ultrasound scanning technique -- could save many lives.
Treating advanced prostate cancer is very difficult. "If we catch it early, that is our best shot," Crawford said.