Efficacy and safety of prostate-targeted local therapy in patients with newly diagnosed oligometastatic prostate cancer: a systematic review and meta-analysis

Abstract

BackgroundThe role of local therapy for the management of oligometastatic prostate cancer at diagnosis still remains poorly defined. We did a systematic review and meta-analysis evaluating local therapy of the primary tumour for patients with oligometastatic prostate cancer at diagnosis as well as the patients who can benefit the most. MethodsFor this systematic review, we searched PubMed, EMBASE, Medline, and the Cochrane Library for studies from database inception until March, 2016, for local therapy of the primary tumour in patients with oligometastatic prostate cancer. No language restrictions were applied. We estimated the risk of bias for the individual research studies using the Newcastle-Ottawa Scale (NOS). We assessed the publication bias using both the Egger's linear regression approach and funnel plots. The baseline characteristics on trial, patient, and treatment level were extracted. The primary outcomes were overall survival and disease-specific survival. All statistical analyses were performed using Stata v.12.0 software (StataCorp, College Station, TX, USA). FindingsSeven retrospective studies were selected for inclusion, including a total of 24 203 patients who were recruited from 1989 to 2010 form Sweden, USA, and Germany. For overall survival, the pooled hazard ratio (HR) in patients treated with local therapy compared with no local therapy was 0·53 (95% CI 0·40–0·71; p <0·01). Local therapy was also associated with a 49% improvement of disease-specific survival (HR 0·51, 95% CI 0·37–0·69, p<0·01). This significant increase in disease-specific survival was better pronounced in patients younger (HR 0·34, 0·23–0·52, p<0·01) than 65 years than in those 65 years or older (HR 0·44, 0·28–0·68, p <0·01). The tumour-specific factor was associated with the improved survival in patients with AJCC (American Joint Committee on Cancer) M1a stage (HR 0·29, 0·18–0·48, p<0·01) than in those with M1b (HR 0·40, 0·24–0·68, p<0·001) and M1c (HR 0·34; 0·24–0·50, p<0·01). InterpretationLocal therapy for a primary tumour conferred a significantly better outcome in fit patients with oligometastatic prostate cancer at diagnosis. The evidence also suggests that radical prostatectomy is a preferable local therapy procedure for patients aged 65 years or younger or for those who have an AJCC stage M1a tumour. We believe that important local therapy factors should be systematically assessed to develop a personalised approach to improve patient survival FundingThis study was supported by the Prostate Cancer Foundation Young Investigator Award 2013, the National Natural Science Foundation of China (81300627 and 81370855) and Programs from Science and Technology Department of Sichuan Province (2013SZ0006 and 2014JY0219).