Improving patient selection for selective internal radiation therapy of intra‐hepatic cholangiocarcinoma: A meta‐regression study

Abstract Background & Aims Selective internal radiation therapy ( SIRT ) is emerging as a potential therapy for unresectable intra‐hepatic cholangiocarcinoma ( iCCA ) able to prolong life‐expectancy. Aim of this study was to collect available literature meta‐analyse data and results and investigate sources of heterogeneity through a meta‐regression approach before suggesting SIRT as a valuable option. Methods A systematic review of studies published until 1 September 2016 in PubMed and Scopus databases was performed. Patient survival was the primary outcome measure. Meta‐analysis was performed using a random‐effects model. Meta‐regression was applied to investigate relationships existing between clinical and tumour features and the primary outcome. Results Nine observational studies were included in the analysis involving 224 patients. The 1‐, 2‐ and 3‐year pooled survival estimates were 55.7%, 33.1% and 20.2%. Clinical and tumour characteristics showed medium‐to‐considerable heterogeneity ( I 2 >50%). Meta‐regression analysis showed that determinants of best survivals were the presence of mass‐forming iCCA type (median survival=19.9 months vs 8.1 months for the infiltrative type; P =.002) that also accounted for most of the heterogeneity between included studies (residual I 2 =0); SIRT as first‐line therapy (median survival=24 months vs 11.5 months for non‐naïve patients; P =.048) and the adoption of concomitant chemotherapy (median survival 19.5 months vs 5.5 months in patients not receiving chemotherapy; P =.042). Conclusions There is considerable heterogeneity between studies highlighting that indications for SIRT are extremely varied. To ameliorate SIRT results naïve patients with mass‐forming iCCA should be selected as the best candidates with the possibility of adding concomitant standard chemotherapy.