Objectives. To test whether preoperative insulin-like growth factor (IGF)-I levels could predict pathologic stage and prognosis of prostate cancer in patients undergoing radical prostatectomy.

Methods. The study group consisted of 120 consecutive patients who underwent radical prostatectomy for clinically localized prostate cancer. Preoperative plasma IGF-I levels were measured using the DSL-IGF-I Elisa assay. Surgically removed prostate specimens were analyzed pathologically, using a whole-mount step-section technique. Preoperative plasma IGF-I levels were compared with final pathologic parameters and with prostate-specific antigen (PSA) progression-free survival. Preoperative IGF-I levels in this cohort were also compared with IGF-I levels measured in 20 healthy men without any cancer and in 10 men with untreated, metastatic prostate cancer.

Results. Plasma IGF-I levels predicted neither organ-confined disease (P = 0.5611) nor the risk of PSA progression (P = 0.8125) at a median follow-up of 48.6 months after prostatectomy. Furthermore, IGF-I levels did not correlate with preoperative PSA level (P = 0.2811) or final Gleason score (P = 0.4906). IGF-I levels in radical prostatectomy patients were not significantly higher than those in healthy subjects or in patients with metastatic disease (mean 156.7 ± 66 ng/mL, 148.6 ± 49 ng/mL, and 148.6 ± 93 ng/mL, respectively; P = 0.8442).

Conclusions. Circulating IGF-I levels may predict the future risk of developing prostate cancer, but our study found no association with other established markers of biologically aggressive disease or with disease progression in patients with clinically localized prostate cancer.