Neuroendocrine differentiation is not prognostic of failure after radical prostatectomy but correlates with tumor volume

Objectives. To study neuroendocrine (NE) tumor cell differentiation in pros tate cancer in relation to failure after radical prostatectomy. Methods. Radical prostatectomy specimens from 103 of 111 patients randomize d to 3-month neoadjuvant luteinizing hormone-releasing hormone-analogue tre atment (neoadjuvant group) or to surgery alone (control group) were availab le for analysis. Immunohistochemistry using antibodies to chromogranin A (C GA) enabled detection of tumor cells with NE differentiation. NE differenti ation was scored as NE-negative (0 to 1+) or NE-positive (2 to 3+). The num ber of CGA-positive cells/cm(2) tumor area on the slides was assessed in a separate analysis. The patients were followed up for 39 months after surger y, and a prostate-specific antigen value of 0.5 ng/mL or greater in two con secutive blood samples was considered biochemical failure. Results. Kaplan-Meier analysis stratified for neoadjuvant hormonal treatmen t showed the failure rate to be significantly greater among those with NE-p ositive tumors than among those with NE-negative tumors. However, the numbe r of CGA-positive cells/cm(2) was not a variable of prognostic significance . Instead, both NE differentiation and the CGA-positive cell count correlat ed with the tumor area on the slides (P = 0.0001). Multivariate analysis re vealed the tumor area on the slide (P <0.0001) and positive surgical margin s (P = 0.03) to be the only significant predictors of biochemical failure. Conclusions. The extension of NE differentiation in prostate cancer correla tes with tumor volume and is not an independent prognostic factor of failur e after radical prostatectomy. UROLOGY 56: 1011-1015, 2000. (C) 2000, Elsev ier Science Inc.