Retrospective analysis of the role of adjuvant chemotherapy and microRNAs expression in resected cholangiocarcinomas (CCAs)

Abstract

Background: Surgery is the only potentially curative treatment for CCAs. Although potential benefit of adjuvant chemotherapy (CT) was suggested in R1 disease, international guidelines recommend adjuvant CT only within clinical trials. Objective of this study was to analyse the effect of adjuvant CT and the prognostic role of microRNAs in a retrospective cohort of CCAs. Material and methods: Clinical data were retrospectively collected from 42 patients who underwent surgical resection for CCA within Humanitas Cancer Center between 1999 and 2014. FFPE tissues were retrieved and subjected to RNA extraction after macrodissection of tumoural and adjacent counterpart. MicroRNA expression was assessed by Taqman assays. Results: Analysis was limited to 31 patients who didn't receive treatment (n:16) or adjuvant CT for >3 months (n:15). These included 15 extrahepatic, 6 intrahepatic and 10 gallbladder cancers. Median follow-up was 22.1 months. Adjuvant CT included single agent gemcitabine (n:6) or combination CT (n:10). Relapse Free Survival (RFS) did not differ according to tumour type (p = 0.9). Patients treated with adjuvant CT had longer median RFS compared to non-treated (22.5 vs 10.4 months, p = 0.0034). Advantage in RFS was maintained in R0 resections (p = 0.0017). We didn't observe differences in RFS according to type of CT (single agent, gemcitabine- or fluorouracil-based). Single agent gemcitabine prolonged median RFS vs no treatment (17.9 vs 10.4 months, p = 0.04). In vitro findings suggested that miR-1249 modulates response to CT in CCA. We observed over-expression of miR-1249 in tumour vs adjacent normal tissues in 36% of cases. Strong expression of miR-1249 in tumour tissues was confirmed in a second cohort of CCA (n:35) by In Situ Hybridization. When miR-1249 tumour expression was considered as a binary predictor, we noticed an association between high miR-1249 expression and shorter RFS (p = 0.05). MiR-1249 was correlated with RFS also in the two subgroups of non-adjuvant (p = 0.0013) and adjuvant CT (p = 0.05). In patients with highmiR-1249 tumours adjuvant CT improved RFS (19.9 vs 3.1 months, p = 0.0003). With multivariate analysis, adjuvant chemotherapy (p = 0.0096) and elevated miR-1249 expression (p = 0.0026) maintained a prognostic role. Conclusions: We showed a significant advantage of adjuvant CT in patients with resected CCA, which was also maintained in R0 resection. In addition we identified miR-1249 as a potential prognostic factor that may identify candidate patients for adjuvant CT.