Department of Radiation Oncology, Oakland University, William Beaumont School of Medicine, Royal Oak, MI.
To determine the prognostic significance of neuroendocrine differentiation (NED) in Gleason score 8-10 prostate cancer treated with primary radiotherapy (RT).
Chromogranin A (CgA) staining was performed and overseen by a single pathologist on core biopsies from 176 patients from the William Beaumont prostate cancer database. A total of 143 had evaluable biopsy material. Staining was quantified as 0%, < 1%, 1-10%, or >10% of tumor cells. Patients received external beam RT alone or together with high-dose-rate brachytherapy. Cox regression and Kaplan-Meier estimates determined if the presence/frequency of neuroendocrine cells correlated with clinical endpoints.
Median follow-up was 5.5 years. Forty patients (28%) had at least focal positive CgA staining (< 1% n = 21, 1-10% n = 11, >10% n = 8). No significant differences existed between patients with or without staining in terms of age, pretreatment prostate-specific antigen, tumor stage, hormone therapy administration, % biopsy core involvement, mean Gleason score, or RT dose/modality. CgA staining concentration independently predicted for biochemical and clinical failure, distant metastases (DM), and cause-specific survival (CSS). For patients with <1% vs. >1% staining, 10-year DM rates were 13.4% vs. 55.3%, respectively (p = 0.001), and CSS was 91.7% vs. 58.9% (p < 0.001). As a continuous variable, increasing CgA staining concentration predicted for inferior rates of DM, CSS, biochemical control, and any clinical failure. No differences in outcomes were appreciated for patients with 0% vs. < 1% NED.
For Gleason score 8-10 prostate cancer, >1% NED is associated with inferior clinical outcomes for patients treated with radiotherapy. This relates most directly to an increase in distant disease failure.
Krauss DJ, Hayek S, Amin M, Ye H, Kestin LL, Zadora S, Vicini FA, Cotant M, Brabbins DS, Ghilezan MI, Gustafson GS, Martinez AA. Are you the author?
Reference: Int J Radiat Oncol Biol Phys. 2011 May 17. Epub ahead of print.