Metastasis-directed therapy of regional and distant recurrences after curative treatment of prostate cancer: a systematic review of the literature

Context: The introduction of novel imaging modalities has increased the detection of oligometastatic prostate cancer (PCa) recurrence, potentially justifying the use of a metastasis-directed therapy (MDT) with surgery or radiotherapy (RT) rather than a systemic approach.

Objective: To perform a systematic review of MDT for oligometastatic PCa recurrence.

Evidence acquisition: This systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. We searched the Medline and Embase databases from 1946 to February 2014 for studies reporting on biochemical or clinical progression and/or toxicity or complications of MDT (RT or surgery). Reports were excluded if these end points could not be ascertained or separately analysed, or if insufficient details were provided. Methodological quality was assessed using an 18-item validated quality appraisal tool for case series.

Evidence synthesis: Fifteen single-arm case series reporting on a total of 450 patients met the inclusion criteria. Seven studies were considered of acceptable quality. Oligometastatic PCa recurrence was diagnosed with positron emission tomography with coregistered computed tomography in most of the patients (98%). Nodal, bone, and visceral metastases were treated in 78%, 21%, and 1%, respectively. Patients were treated with either RT (66%) or lymph node dissection (LND) (34%). Adjuvant androgen deprivation was given in 61% of patients (n=275). In the case of nodal metastases, prophylactic nodal irradiation was administered in 49% of patients (n=172). Overall, 51% of patients were progression free 1-3 yr after salvage MDT, with most of them receiving adjuvant treatment. For RT, grade 2 toxicity was observed in 8.5% of patients, with one case of grade 3 toxicity. In the case of LND, 11% and 12% of grade 2 and grade 3 complications, respectively, were reported.

Conclusions: MDT is a promising approach for oligometastatic PCa recurrence, but the low level of evidence generated by small case series does not allow extrapolation to a standard of care.

Patient summary: We performed a systematic review to assess complications and outcomes of treating oligometastatic prostate cancer recurrence with surgery or radiotherapy. We concluded that although this approach is promising, it requires validation in randomised controlled trials.