Effects of the somatostatin analog lanreotide on the circulating levels ofchromogranin-A, prostate-specific antigen, and insulin-like growth factor-I in advanced prostate cancer patients

BACKGROUND. The concept that neuroendocrine cells detected within prostate adenocarcinoma produce paracrine factors, that may exert a proliferative ef fect on exocrine prostate tumor cells, provides a rationale for the use of somatostatin analogs with the aim to counteract or delay the tumor progress ion. This study was designed to provide preliminary information on the effe ct of the administration of a long-acting somatostatin analog, lanreotide, on plasma levels of chromogranin A (CgA). Secondary aims were the evaluatio n of changes in circulating prostate-specific antigen (PSA) and insulin-lik e growth factor-1 (IGF-1). METHODS. Lanreotide(Ipstyl 30 mg; Ipsen, Milan, Italy) was administered int ramuscularly every 14 days for 2 months to nine heavily pretreated prostate cancer patients with hormone refractory disease. All patients had, at base line conditions, CgA values above the normal range. Androgen deprivation wa s maintained during the study period, while other concomitant antineoplasti c treatments were not allowed. Serum PSA levels and plasma CgA and IGF-1 va lues were measured every week. RESULTS. Lanreotide treatment was very well tolerated and no patient experi enced major toxicity. Plasma CgA values at baseline: mean 109 U/liter, stan dard deviation +/- 85 decreased significantly after treatment as follows: 4 2 U/liter, +/- 17.8; 27.2 U/liter +/- 13.6; 31.4 U/liter, +/- 17.8 and 27.6 U/liter, +/- 17.0; after 7, 14, 21, and 28 days, respectively (P < 0.01, F riedman ANOVA). Serum PSA did not change. Baseline IGF-1 was found to be ab ove the detection limit in four cases, all of them showing a decrease after lanreotide. CONCLUSIONS. Lanreotide administration to prostate cancer patients induces a decrease in plasma CgA and IGF-1 levels, without any influence on serum P SA values. Prostate 47:205-211,2001. (C) 2001 Wiley-Liss, Inc.