Salvage radiation for a rising PSA following radical prostatectomy

Abstract

The purpose of this study was to evaluate the efficacy and complications of postprostatectomy therapeutic irradiation (RT) in patients with known residual disease. Between 1991 and 2003, 170 patients received therapeutic irradiation for a rising PSA following radical prostatectomy. No patients had clinical or radiological evidence of metastatic disease. The median pre-RT PSA level was 1.2 ng/mL (range, 0.2–43 ng/mL). During irradiation, the PSA level was checked weekly (median PSA determinations: 5, range, 2–7). A patient was considered to have a rise/fall of PSA if the level changed by ≥0.2 ng/mL. There were 149 patients who received photon irradiation (median dose, 6800 cGy) and 21 patients received a combination of photon and neutron irradiation to a median photon dose equivalent of 7800 cGy. A patient was considered to have biochemical failure if his PSA level postnadir was measured at >0.2 ng/mL. Complications were graded according to the RTOG toxicity scale. The median follow-up time was 49 months (range, 1–137 months). Sixty-four patients (38%) had evidence of biochemical failure. The 7 year overall survival was 84%. At 7 years, the actuarial biochemical relapse free survival (bRFS) was 44%. Of the 59 patients with a preradiation PSA <1 ng/mL, the 5 year bRFS was 81%. This compares with 45% for both the PSA 1–4 and PSA >4 ng/mL group ( P = 0.00008). The 3-year bRFS rates for patients whose PSA levels increased, decreased, and remained the same during radiation were 20%, 65%, and 76%, respectively ( P = 0.0005). Overall survival at 7 years in the decreased PSA group was 88% compared to 67% for those whose PSA level increased ( P = 0.43). Thirty-three percent and 19% of the patients experienced Grade 2 genitourinary (GU) and gastrointestinal (GI) complications, respectively. Six percent and 3% of the patients had Grade 3 GU and GI complications, respectively. On univariate and multivariate analysis, the factors significantly associated with a favorable outcome were a declining PSA during RT and a pre-RT PSA <1 ng/mL ( P < 0.001). Radiation therapy is an effective treatment modality for select patients with a biochemical recurrence following radical prostatectomy. Patients with a low preradiation PSA level (<1.0 ng/mL) had a significantly better outcome, which supports the early use of therapeutic radiation. The observation that patients with a rising PSA level during treatment do poorly supports the routine practice of monitoring these levels during radiotherapy.