Dose-escalated radiation therapy for intermediate-risk prostate cancer

Patient selection for androgen deprivation therapy using percentage of positive cores


  • Presented at the American Society for Therapeutic Radiology and Oncology 50th Annual Meeting, Boston, Massachusetts, September 2008.



Randomized trials supported the use of androgen deprivation therapy (ADT) with radiation therapy (RT) for intermediate-risk prostate cancer. However, the value of concurrent ADT was less certain with dose-escalated RT. Better methods of stratifying patients in this risk group may help select patients who are most likely to benefit.


A total of 238 men with intermediate-risk (prostate specific antigen [PSA] 10-20, Gleason 7, or stage T2b-c) adenocarcinoma of the prostate were treated with external beam RT between 1989 and 2006. Patients had Gleason≤6 (39%) or 7 (61%) tumors; median PSA was 10.5 ng/mL. A median of 37.5% of biopsy cores were positive from a median of 9 biopsy cores sampled. The median RT dose was 74 Gy to the prostate. A total of 112 patients (47%) received neoadjuvant and concurrent ADT (median, 4 months). Median follow-up period was 49 months.


The freedom from biochemical failure (FFBF, nadir + 2 definition) was 93% at 3 years, 86% at 4 years, and 80% at 5 years. On univariate analysis, the only factor associated with FFBF was percentage of positive cores (PPC, P = .0340). The prognostic value of PPC≥50 was not evident in patients receiving ADT (FFBF at 4 years 90% vs 91%, P = .3015). For patients not receiving ADT, the impact of PPC≥50 (FFBF at 4 years 76% vs 93%, P = .0844) was more pronounced. On multivariate analysis, PPC (P = .0388) was significantly associated with FFBF, whereas Gleason sum, ADT, RT dose, PSA, and T-stage were not.


After dose-escalated external beam RT, intermediate-risk prostate cancer patients with PPC≥50 had the highest risk for biochemical failure and may be most likely to derive a benefit from ADT. Cancer 2009. © 2009 American Cancer Society.