Salvage Stereotactic Radiotherapy for Nodal Oligo-Recurrent Prostate Cancer: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Abstract

Background

Prostate cancer has a high frequency of relapse, and the relapse is usually associated with a nodal recurrence pattern spreading predominantly to fewer pelvic or extra-pelvic lymph nodes. This meta-analysis sought to determine the safety and survival outcomes of salvage body stereotactic radiotherapy (SBRT) in oligo-recurrent nodal prostate cancer patients.

Methods

We searched the Cochrane Central Register of Controlled Trials, PubMed, ClinicalTrials.gov, and Google Scholar to retrieve all the relevant randomized controlled trials (RCTs) from inception to May 2024. Dichotomous outcomes were pooled using risk ratios (RR) with a 95% confidence interval (CI), whereas survival outcomes were reported using hazard ratios (HR) with a 95% CI.

Results

Three RCTs with a total of 312 patients (median age range of >18-79) were included. Of 312 patients, 135 received SBRT with medical therapy, while 122 underwent either observation, medical therapy, or elective nodal radiotherapy. SBRT significantly increased the biochemical recurrence-free survival (HR: 0.45; 95% CI, 0.28-0.73) with minimal inter-study heterogeneity (I2 = 0%). SBRT did not affect the grade 2 genitourinary (GU) toxicity levels (Common Terminology Criteria for Adverse Events [CTCAE] v4.0) (RR: 0.74; 95% CI, 0.32-1.70; (I2 = 0%) nor the grade 2 gastrointestinal (GI) toxicity levels (CTCAE v4.0) (RR: 1.05; 95% CI, 0.26-4.31; I2 = 0%). SBRT was not associated with any significant change in the grade 1 toxicity levels (CTCAE v4.0) (RR, 1.08; 95% CI, 0.62-1.89) with moderate heterogeneity (I2 = 63%).

Conclusion

SBRT improves biochemical recurrence-free survival in patients with oligo-recurrent prostate cancer without increasing grade 1 and grade 2 GU/GI toxicity levels.