Serum insulin-like growth factor I/free prostate specific antigen (IGF-I/fPSA) ratio enhances prostate cancer detection in men with total PSA 4.0-10.0 ng/ml

Background Recent studies have suggested that IGF‐I and IGFBP‐3, in combination with PSA, may enhance PCa detection. This study was to investigate the use of serum IGF‐I and IGFBP‐3, and their combinations with prostate volume and fPSA in enhancing the discriminatory diagnosis of PCa in men with tPSA of 4.0–10.0 ng/ml. Methods Serum IGF‐I and IGFBP‐3 were determined by ELISA from 586 men with tPSA between 4.0 and 10.0 ng/ml. Of them, 281 were diagnosed with PCa and 305 without. ROC, univariate and multivariate logistic regression analyses were performed to evaluate the predictive performance of those parameters. Results IGF‐I, IGFD, IGF‐I/fPSA, and IGFBP‐3/fPSA were significantly higher in PCa cases than benign controls, whereas the differences of IGFBP‐3 and IGFBPD were statistically insignificant between the two groups, respectively. The AUC values indicated enhanced performance of IGF‐I/fPSA ratio (AUC = 0.753) in PCa detection compared with the currently used f/tPSA (AUC = 0.689). Multivariate logistic regression confirmed the observed relationships and identified IGF‐I/fPSA as independent factor in PCa presence. Conclusion Our data show that IGF‐I/fPSA as a promising marker can enhance PCa detection in ambiguous cases often found in the tPSA between 4.0 and 10.0 ng/ml. J. Surg. Oncol. 2007;96:54–61. © 2007 Wiley‐Liss, Inc.