CORRESPONDENCE

Re: Insulin-Like Growth Factor-I (IGF-I) and IGF Binding Protein-3 as Predictors of Advanced-Stage Prostate Cancer

Steven Lehrer, Edward J. Diamond, Michael J. Droller, Nelson N. Stone, Richard G. Stock

Affiliations of authors: S. Lehrer, R. G. Stock (Department of Radiation Oncology), E. J. Diamond (Department of Medicine, Endocrinology), M. J. Droller and N. N. Stone (Department of Urology), Mount Sinai School of Medicine, New York, and the Veterans Affairs Medical Center, Bronx, NY.

Correspondence to: Steven Lehrer, M.D., Radiation Oncology, Box 1236, Mount Sinai Medical Center, New York, NY 10029 (e-mail: stevenlehrer{at}hotmail.com).

A recent study (1) suggested that elevated plasma levels of insulin-like growth factor-I (IGF-I) were a predictor of advanced-stage prostate cancer. We have studied IGF-I in prostate cancer and have found no relationship to disease stage.

We studied IGF-I in a group of 126 men with prostate cancer and benign prostatic hypertrophy (BPH). Participants in our study were found through urology and radiation oncology clinics, and all eligible patients were asked to take part. All cancer patients had initially been diagnosed on the basis of levels of prostate-specific antigen (PSA) or abnormal physical examination. All men with BPH had had negative prostate biopsy examinations. Histologic confirmation of cancer diagnosis was also obtained for all subjects. All participants gave written informed consent. All staging of cancer cases was clinical, because almost all of the patients were to receive 125I seed implant therapy. Serum IGF-I was measured by use of the Nichols Advantage, an automated chemiluminescent immunoassay analyzer (Nichols Institute Diagnostics, San Juan Capistrano, CA).

There was no statistically significant difference in the IGF-I levels in men with BPH compared with those in men with prostate cancer, nor was there statistically significant variation of IGF-I level among men with stages T1, T2, or T3 prostate cancer (P = .323, one-way analysis of variance; Fig. 1Go). Multivariable linear regression revealed no statistically significant effect of PSA level, Gleason score, or T stage on IGF-I level (P = .277) in men with prostate cancer.



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Fig. 1. Serum insulin-like growth factor-I (IGF-I) levels in patients with stage T1, T2, and T3 prostate cancer and men with benign prostatic hypertrophy (BPH) without prostate cancer (bars represent mean + SD). The number of patients in each group is indicated above corresponding error bar. There is no statistically significant difference in IGF-I levels in the four groups (P = .323, one-way analysis of variance).

 
Shariat et al. (2) have shown that systemic levels of IGF-I are not associated with metastasis, established markers of biologically aggressive disease, or disease progression in patients with clinically localized prostate cancer. Our results agree with those of Shariat et al. and suggest that serum IGF-I levels are not related to advanced-stage prostate cancer.

REFERENCES

1 Chan JM, Stampfer MJ, Ma J, Gann P, Gaziano JM, Pollak M, et al. Insulin-like growth factor-I (IGF-I) and IGF binding protein-3 as predictors of advanced-stage prostate cancer. J Natl Cancer Inst 2002;94:1099–106.[Abstract/Free Full Text]

2 Shariat SF, Bergamaschi F, Adler HL, Nguyen C, Kattan MW, Wheeler TM, et al. Correlation of preoperative plasma IGF-I levels with pathologic parameters and progression in patients undergoing radical prostatectomy. Urology 2000;56:423–9.[Medline]



             
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