Prognostic role of metformin in diabetes mellitus type 2 patients with hepatocellular carcinoma:A systematic review and meta-analysis

BACKGROUND Hepatocellular carcinoma(HCC)is among the commonest malignancies associated with significant cancer-related death.The identification of chemopreventive agents following HCC treatments with the potential to lower the risk of HCC adverse course is intriguing.Metformin,a first-line agent used in the treatment of type 2 diabetes mellitus(T2DM),has been associated with inhibition of HCC growth.AIM To determine whether metformin can prevent adverse events(i.e.,death,tumor progression,and recurrence)after any HCC treatment in T2DM patients.METHODS A systematic review of the published literature was undertaken focused on the role of metformin on outcomes in patients with T2DM and HCC receiving any tumor therapy.A search of the PubMed and Cochrane Central Register of Controlled Trials Databases was conducted.RESULTS A total of 13 studies(n=14886 patients)were included in this review.With regard to the risk of death,a decreased risk was reported in cases receiving metformin,although this decrease was not statistically significant[odds ratio(OR)=0.89,P=0.42].When only patients treated with curative strategies were considered,a more marked correlation between metformin and favorable cases was reported(OR=0.70,P=0.068).When analyzing palliative treatment,there was no statistical significance in terms of the correlation between metformin and favorable cases(OR=0.74,P=0.66).As for the risks of progressive disease and recurrence,no obvious correlation between metformin use and reduced risk was reported.When sub-analyses were performed for patients from different regions,the results for patients from Eastern countries showed a tendency for decreased risk of death in T2DM cases receiving metformin(OR=0.69,P=0.17),but the same was not seen in patients from Western countries(OR=1.19,P=0.31).CONCLUSION Metformin failed to show a marked impact in preventing adverse effects after HCC treatment.A trend was reported in T2DM cases receiving curative therapies in relation to the risk of death,especially in patients from Eastern regions.Great heterogeneity was reported among the different studies.Further large studies are required to definitively clarify the real impact of metformin as a chemopreventive agent for HCC.

Platelet-to-lymphocyte ratio in the setting of liver transplantation for hepatocellular cancer: A systematic review and meta-analysis

AIM To perform a systematic review and meta-analysis on platelet-to-lymphocyte ratio(PLR) as a risk factor for post-transplant hepatocellular cancer(HCC) recurrence. METHODS A systematic literature search was performed using PubM ed. Participants of any age and sex, who underwent liver transplantation for HCC were considered following these criteria:(1) studies comparing pre-transplant low vs high PLR values;(2) studies reporting post-transplant recurrence rates; and(3) if more than one study was reported by the same institute, only the most recent was included. The primary outcome measure was set for HCC recurrence after transplantation. RESULTS A total of 5 articles, published between 2014 and 2017, fulfilled the selection criteria. As for the quality of the reported studies, all the investigated articles presented an overall high quality. A total of 899 cases were investigated: 718 cases(80.0%) were males. Three studies coming from European countries and one from Japan presented HCV as the main cause of cirrhosis. On the opposite, one Chinese study presented a greater incidence of HBV-related cirrhotic cases. In all the studies apart one, the PLR cut-off value of 150 was reported. At meta-analysis, high PLR value was associated with a significant increase in recurrence after transplantation(OR = 3.33; 95%CI: 1.78-6.25; P < 0.001). A moderate heterogeneity was observed among the identified studies according to the Higgins I^2 statistic value.CONCLUSION Pre-transplant high PLR values are connected with an increased risk of post-operative recurrence of hepatocellular cancer. More studies are needed for better clarify the biological mechanisms of this results.

Donor-to-recipient gender match in liver transplantation: A systematic review and meta-analysis

AIM To perform a systematic review and meta-analysis on donor-to-recipient gender mismatch as a risk factor for post-transplant graft loss. METHODS A systematic literature search was performed using PubM ed, Cochrane Library database and EMBASE. The primary outcome was graft loss after liver transplantation. Odds ratios and 95% confidence intervals were calculated to compare the pooled data between groups with different donor-to-recipient gender matches. Three analyses were done considering(1) gender mismatches(F-M and M-F) vs matches(M-M and F-F);(2) Femaleto-Male mismatch vs other matches; and(3) Male-toFemale mismatch vs other matches.RESULTS A total of 7 articles were analysed. Gender mismatch(M-F and F-M) was associated with a significant increase of graft loss respect to match(M-M and F-F)(OR: 1.30; 95%CI: 1.13-1.50; P < 0.001). When F-M mismatch was specifically investigated, it confirmed its detrimental role in terms of graft survival(OR: 1.83; 95%CI: 1.20-2.80; P = 0.005). M-F mismatch failed to present a significant role(OR: 1.09; 95%CI: 0.73-1.62; P = 0.68).CONCLUSION Gender mismatch is a risk factor for poor graft survival after liver transplantation. Female-to-male mismatch represents the worst combination. More studies are needed with the intent to better clarify the reasons for these results.