Radiation therapy for increasing prostate-specific antigen levels after radical prostatectomy.

ABSTRACT

Herein we present data on outcomes in patients with increasing prostate-specific antigen (PSA) levels treated with irradiation to the pelvis and/or prostatic bed after radical prostatectomy. Between 1988 and 1998, 92 patients who presented with increasing PSA levels after radical prostatectomy were treated with irradiation, 29 to the pelvis and prostatic bed and 63 to the prostatic bed only. The mean follow-up was 4 years for the 3D-CRT group and 6.5 years for the standard radiation therapy group. Criterion for biochemical failure was an increase in post irradiation PSA level on > or = 1 consecutive measurement. Patients were classified into 3 risk groups based on prognostic factors pathologic tumor extent and stage, Gleason score, and PSA levels before irradiation. Acute and late morbidity was quantitatively evaluated in all patients. There was a close correlation between the preirradiation PSA level and the probability of 4-year biochemical failure-free survival (75% with PSA levels < or = 1 ng/mL, 30% with PSA levels of 1.1-2 ng/mL, and 20% with PSA levels > 2 ng/mL; P = 0.05). The 4-year chemical failure rate was 20% in the low/intermediate-risk group and 65% in the high-risk group (P = 0.36). In 20 patients in the low-PSA group (< or =1 ng/mL) receiving doses > 62 Gy, no biochemical failures have been detected in comparison to a 70% failure rate at 4 years in patients treated with lower doses (P = 0.15). In the higher-PSA groups, no impact of irradiation dose on outcome was noted (40%-60% incidence of failure at 3 years). Pelvic irradiation was associated with a trend toward decreased biochemical failure rate in the low-PSA group (70% vs. 0% at 4 years; P = 0.35), but not in the high-PSA group. Only 1 patient (1.5%) experienced clinical local recurrence in the prostatic bed and 2 patients (1.8%) had distant metastases. Treatment has been very well tolerated, with only 3 patients in the arc-rotation group experiencing grade 2 treatment toxicity. Prostate bed irradiation is an effective treatment in a significant proportion of patients who present with a biochemical failure after radical prostatectomy.