Conventional Versus Hypofractionated Radiation Therapy for Localized or Locally Advanced Prostate Cancer: A Systematic Review and Meta-analysis along with Therapeutic Implications

Purpose: A systematic review and meta-analysis were conducted to evaluate the therapeutic outcomes of conventional radiation therapy (CRT) and hypofractionated radiation therapy (HRT) for localized or locally advanced prostate cancer (LLPCa). Methods and Materials: A total of 599 abstracts were extracted from 5 databases and screened in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Only phase III trials randomized between CRT and HRT in LLPCa with a minimum of 5 years of follow-up data were considered. The evaluated endpoints were biochemical failure, biochemical and/or clinical failure, overall mortality, prostate cancer-specific mortality, and both acute and late gastrointestinal (GI) and genitourinary (GU) (grade >= 2) toxicity. Results: Ten trials from 9 studies, with a total of 8146 patients (CRT, 3520; HRT, 4626; 1 study compared 2 HRT schedules with a common CRT regimen), were included in the evaluation. No significant differences were found in the patient characteristics between the 2 arms. However, the RT parameters differed significantly between CRT and HRT (P<.001 for all). The use of androgen deprivation therapy varied from 0% to 100% in both groups (mean +/- standard deviation 43.3% +/- 43.6% for CRT vs HRT; P = NS). The odds ratio, risk ratio, and risk difference (RD) between CRT and HRT for biochemical failure, biochemical and/or clinical failure, overall mortality, prostate cancer-specific mortality, acute GU toxicity, and late GU and GI toxicities were all nonsignificant. Nevertheless, the incidence of acute GI toxicity was 9.1% less with CRT (RD 0.091; odds ratio 1.687; risk ratio 1.470; P<.001 for all). On subgroup analysis, the patient groups with <= 66.8% versus >66.8% androgen deprivation therapy (RD 0.052 vs 0.136; PZ = .008) and <76% versus >= 76% full seminal vesicles in the clinical target volume (RD 0.034 vs 0.108; P<.001) were found to significantly influence the incidence of acute GI toxicity with HRT. Conclusions: HRT provides similar therapeutic outcomes to CRT in LLPCa, except for a significantly greater risk of acute GI toxicity. HRT enables a reduction in the overall treatment time and offers patient convenience. However, the variables contributing to an increased risk of acute GI toxicity require careful consideration. (C) 2017 Elsevier Inc. All rights reserved.