Efficacy of adjuvant and salvage image-guided radiotherapy in post-radical prostatectomy patients

Abstract

Objective To analyze the clinical efficacy and toxicity of adjuvant (ART) and salvage radiotherapy (SRT) after prostatectomy for prostate carcinoma, and to investigate the variation and significance of prostate-specific antigen (PSA) level. Methods A retrospective study was performed on the clinical data of 58 patients receiving intensity-modulated radiotherapy after prostatectomy from November 2008 to August 2015. In those patients, 21 received ART and 37 SRT. The median dose delivered to the 95% planning target volume (PTV) of the prostate and seminal vesicles tumor bed was 74 Gy, and 95% PTV of the pelvic lymph nodes was 50 Gy. The survival rate was calculated by Kaplan-Meier method. Used Pearson correlation analysis. Results The median follow-up time was 36.2 months. The 3-year biochemical relapse-free survival, tumor-specific survival, and overall survival rates were 81.8%, 100%, and 96%, respectively. In all patients, the median time to PSA nadir after radiotherapy was 3 months with a mean level of PSA nadir of 0.04 ng/ml. In patients treated with ART, the median PSA level before radiotherapy was 0.034 ng/ml; the median time from surgery to radiotherapy was 5.4 months; the mean time to PSA nadir after radiotherapy was 4.6 months. In patients treated with SRT, the median PSA level before radiotherapy was 0.540 ng/ml; the median time from surgery to radiotherapy was 69.7 months; the mean time to PSA nadir after radiotherapy was 9.4 months. The incidence rates of grade 1 and 2 short-term genitourinary (GU) toxicity were 55% and 2%, respectively, while the incidence rates of grade 1 and 2 long-term GU toxicity were 10% and 16%, respectively. The incidence rates of grade 1 and 2 short-term gastrointestinal (GI) toxicity were 30% and 8%, respectively, while the incidence rates of grade 1 and 2 long-term GI toxicity were 9% and 3%, respectively. No patients had grade 3 or 4 toxicity. Rectum D50 was significantly related with acute and late GI side effects (P=0.012、0.026). Conclusions Both ART and SRT achieve satisfactory treatment outcomes and low short-and long-term toxicity. Compared with ART, SRT has a longer time to PSA nadir. Key words: Prostate neoplasms/postoperative radiotherapy; Radiotherapy, image-guided; Radiotherapy, adjuvant; Radiotherapy, salvage; Prognosis; Prostate-specific antigen; Untoward effect