Quality of Life Outcomes Following Stereotactic Body Radiotherapy in Patients with Oligo-Metastatic Disease: A Systematic Review and Meta-Analysis.

PURPOSE/OBJECTIVE(S) The management of oligo-metastatic disease (OMD) is evolving, with increasing data supporting the use of stereotactic body radiotherapy. The aim of this systematic review and meta-analysis is to analyses health related quality of life (HRQOL) outcomes and the side-effects of SBRT in patients with OMD. MATERIALS/METHODS We searched MEDLINE, Epub Ahead of Print, EMBASE, Cochrane CT, Cochrane SR, Emcare, and PsycInfo databases (from inception to March 2020). Randomized clinical trials (RCTs) or observational studies were included if HRQOL outcomes were reported from patients with defined OMD (£5 metastases) who received SBRT as metastasis-directed therapy, and who completed validated HRQOL questionnaires at baseline and 12-months. Meta-analysis using weighted mean difference was performed to estimate a difference between baseline and 12-month scores. Secondary outcome, calculated by the pooled incidence rate approach using the inverse variance method, was the estimated event rate of clinically significant Common Terminology Criteria for Adverse Events (CTCAE) grade 2-4 and grade 5 toxicity, expressed per person-time of follow-up. Authors of studies included were contacted to obtain additional information. Methods adhered to PRISMA guidelines. RESULTS Four of 7,545 studies screened were eligible for inclusion. Two studies were phase II RCTs and two were prospective single arm studies. Among 277 patients who received SBRT, median follow-up was 31 months (range 24-41 months). Two studies included only prostate cancer patients and two studies included mixed histologies. Two studies measured European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and two measured Functional Assessment of Cancer Therapy - General (FACT-G) scores. Using a fixed effects model, the mean change in 12-month EORTC QLQ-C30 global health QOL score from baseline demonstrated a statistically significant decline (pooled weighted mean difference -5.2, 95% CI -9.3 to -1.2, both prostate cancer studies, 57 patients total). Meta-analysis of total FACT-G scores in the other two studies was not possible as mean difference results for one study were unavailable. For the available multi-histology study, no statistically significant difference was seen in baseline to 12-month mean FACT-G total scores in the SBRT arm. We estimated an event rate of 0.06 (95% CI: 0.024, 0.15) CTCAE grade 2-4 toxicities per person-year and 0.008 (95% CI: 0.002, 0.031) grade 5 toxicities per person-year. CONCLUSION Although a statistically significant decline in the EORTC QLQ C30 global health/QOL measure was seen, it was small and unlikely to be of clinical importance. Rates of SBRT-related clinical toxicities are low. There is limited QOL data published for patients with OMD, with varying HRQOL tools used.