Stereotactic radiotherapy of nodal oligometastases from prostate cancer: a prisma-compliant systematic review

Androgen deprivation therapy (ADT) is the standard treatment of metastatic prostate cancer (PCa). However, metastases-directed therapies can delay the initiation or switch of systemic treatments and allow local control (LC) and prolonged progression-free survival (PFS), particularly in patients with lymph nodes (LN) oligometastases. We performed a systematic review on stereotactic body radiotherapy (SBRT) in this setting. Papers reporting LC and/or PFS were selected. Data on ADT-free survival, overall survival, and toxicity were also collected from the selected studies. Fifteen studies were eligible (414 patients), 14 of them were retrospective analyses. A high heterogeneity was observed in terms of patient selection and treatment. In one study SBRT was delivered as a single 20 Gy fraction, while in the others the median total dose ranged between 24 and 40 Gy delivered in 3-6 fractions. LC and PFS were reported in 15 and 12 papers, respectively. LC was reported as a crude percentage in 13 studies, with 100% rate in seven and 63.2-98.0% in six reports. Five studies reported actuarial LC (2-year LC: 70.0-100%). PFS was reported as a crude rate in 11 studies (range 27.3-68.8%). Actuarial 2-year PFS was reported in four studies (range 30.0-50.0%). SBRT tolerability was excellent, with only two patients with grade 3 acute toxicity and two patients with grade 3 late toxicity. SBRT for LN oligorecurrences from PCa in safe and provides optimal LC. However, the long-term effect on PFS and OS is still unclear as well as which patients are the best candidate for this approach.

Automated summary

Androgen deprivation therapy (ADT) is the standard treatment for metastatic prostate cancer (PCa), but metastases-directed therapies such as stereotactic body radiotherapy (SBRT) can delay systemic treatments and provide local control and prolonged progression-free survival. Our systematic review found that SBRT is safe and effective in achieving optimal local control in patients with lymph node oligometastases from PCa.