The use of prostate-specific antigen in staging patients with newly diagnosed prostate cancer.

OBJECTIVE

To assess the need for obtaining radionuclide bone scans in the staging evaluation of patients with newly diagnosed, untreated prostate cancer. This determination was made on the basis of presenting prostate-specific antigen (PSA) levels.

DESIGN

Retrospective review.

PARTICIPANTS

The medical records of 2064 consecutive patients with prostate cancer who were evaluated at the Mayo Clinic in Rochester, Minn, from January 1989 through December 1990 were reviewed. Eight hundred fifty-two patients with newly diagnosed, untreated disease and a serum PSA concentration less than 20.0 micrograms/L at presentation comprised the study population.

MAIN OUTCOME MEASURE

The rate of false-negative results associated with using the serum PSA concentration to predict bone scan findings.

RESULTS

Five hundred sixty-one patients had a serum PSA concentration of 10.0 micrograms/L or less; only three had an abnormal bone scan result, and one had an indeterminate scan result. Of the 467 men whose PSA value was 8.0 micrograms/L or less (two times the upper limit of the reference range), none had bone scan results that were either abnormal or indeterminate. The rate of false-negative results for an abnormal bone scan result was 0% with a serum PSA value of 8.0 micrograms/L or less and 0.5% with a cutoff level of 10.0 micrograms/L. The 95% upper confidence limit for the rate of false-negative results for all PSA cutoff levels less than 20.0 micrograms/L was less than 2%.

CONCLUSIONS

For patients with newly diagnosed, untreated prostate cancer, a serum PSA concentration of 10.0 micrograms/L or less, and no skeletal symptoms, a staging radionuclide bone scan does not appear to be necessary. This clinical situation applies to 39% of all patients presenting with newly diagnosed prostate cancer. Since more than 130,000 new cases are diagnosed each year, approximately 50,000 patients are affected annually. If the $600 staging bone scan were eliminated for these patients, a significant economic savings to the health care system in this country would be effected.