A systematic review examining clinical markers and biomarkers of analgesic response to radiotherapy for cancer-induced bone pain.

INTRODUCTION: Cancer frequently spreads to bone, causing cancer-induced bone pain (CIBP) which affects quality of life. The best treatment is radiotherapy (XRT), but response is variable. The aim of this systematic review was to identify factors that predict analgesic response.

MATERIALS AND METHODS: Using PRISMA guidelines, Medline (1946-2018), Embase Classic + Embase (1947-2018) and Cochrane (setup-2018) databases were searched. Eligible studies examined adult patients receiving external beam XRT for CIBP with clinical marker and/or biomarkers evaluated.

RESULTS: Twenty-one studies (n = 4490) were included: Urinary markers in three studies (n = 357), genomic biomarkers in one study (n = 107), imaging techniques in five studies (n = 231) and demographics and disease parameters in eight studies (n = 4572). Quantitative sensory testing (n = 23) and physical activity and/or gait (n = 42) have been examined in one study each, while two studies have evaluated grade of spinal instability (n = 276).

CONCLUSION: No predictors of analgesic response from XRT in CIBP were identified but several show promise.