Are PSA baseline levels an indicator for suitability of intermittent androgen deprivation in patients with PSA relapse after radical prostatectomy?

Abstract

136 Background: Intermittent androgen deprivation (IAD) for prostate cancer patients is currently discussed as a treatment option to improve quality of life and to delay hormone resistance. So far only limited data are available indicating whether certain subgroups of patients with PSA relapse without local recurrence after radical prostatectomy are best suited for this therapy. Methods: In a prospective randomized phase III trial, men with unfavourable prognostic factors and a systemic PSA progression (PSA ≥ 1ng/ml) following an initial fall to < 0.5 ng/ml within 3 months after radical prostatectomy were enrolled. They underwent a 6-months androgen deprivation (AD) induction phase with a microencapsulated leuprorelin acetate 3-month depot formulation plus an overlapping antiandrogen to prevent tumor flare-up. Achieving a PSA level < 0.5 ng/ml, they were randomized to either an IAD treatment arm or to continuous AD. In the IAD arm, retreatment was started when PSA rose to ≥ 3 ng/ml. During Off-Treatment-Time (OTT) PSA and Testosterone were controlled on a monthly basis. Results: Analysis of the first IAD cycle, confined as induction phase + OTT, revealed two subgroups of patients with a cycle length ≤ 15 months (group 1) and ≥ 20 months (group 2) respectively. This was due to a significant difference in the time from testosterone normalization (≥ 2.3 ng/ml, TN) to an increased PSA-value ≥ 3 ng/ml. See Table. Conclusions: Our data show a significant (p=0.001) relationship of low PSA baseline levels to delayed biochemical PSA progression during OTT. Thus IAD might be most suitable for patients with low PSA baseline levels leading to a slow increase of PSA after TN during OTT, providing time to improve quality of life and delay potential hormone resistance. Further large scale studies will be necessary to confirm our findings. Clinical trial information: AP 06/95.[Table: see text]