[The relationship between the serum level of prostate specific antigen and bone and CT scans in the staging of the primary carcinoma of the prostate].
OBJECTIVE: To determine the relationship between the serum level of prostate-specific antigen (PSA) and the presence of abnormalities in a skeletal or CT scan in patients with primary carcinoma of the prostate. DESIGN: Retrospective. SETTING: Academic Medical Centre, Amsterdam. PATIENTS AND METHODS: The serum PSA levels were compared with the findings in the skeletal and CT scans of 440 patients with carcinoma of the prostate without clinical signs of metastases, seen in the period from January 1990 to December 1994 in the outpatient clinics for Urology of the Academic Medical Centre (AMC) in Amsterdam, Hospital Gooi-Noord in Blaricum and Hospital De Heel in Zaandam. CT scan data were analysed only from the AMC and Hospital Gooi-Noord. RESULTS: There were 76 patients with a positive bone scan (17.3%) and 31 (out of 337; 9.2%) with a positive CT scan. Higher PSA serum levels went together with increasing risk of abnormalities in bone or CT scan. Of 85 patients with PSA values < 10 micrograms/l, none had a positive bone scan and one (out of 73; 1%) a positive CT scan; of the 180 patients with PSA levels < 20 micrograms/l, 4 (2.2%) had a positive bone scan and 2 (out of 154; 1.3%) a positive CT scan. The T stage, the histological grading and the serum alkaline phosphatase activity appeared not to have any supplementary value. CONCLUSION: In view of the low frequency of abnormalities in a bone or CT scan in patients with low PSA levels, it appears justified no longer to recommend bone or CT scanning for staging of patients for a clinically non-metastasized carcinoma of the prostate and serum PSA levels < 20 micrograms/l.