The pathological stage at surgery is one of the most reliable prognostic indicators in patients with prostate cancer. We examined the influence of the modality of diagnosis and the prostatic-specific antigen (PSA) level on the rate of organ-confined cancer, positive surgical margins and lymph node metastasis in 345 patients treated by radical surgery. The mean PSA and Gleason score were significantly lower in patients detected by screening (n=144) compared to patients detected by routine examination (n=102) or because of urological symptoms (n=89) while the mean age was similar in the three groups (62.5 years). The rate of lymph node metastasis was correlated with the PSA level and ranged from 0% in patients with a normal PSA level (< 4mg/L) up to 33% in patients with a PSA above 20 mg/L, screened patients had a significantly lower rate of lymph node metastasis. Thus the diagnostic modality may be an important prognostic factor to consider in clinical staging.