In most centres, the choice of the optimal activity to be administered in selective intra-arterial radioembolization with microspheres is nowadays based on empirical models which do not take into account the evaluation of tumour and non tumour individual absorbed dose, despite plenty of published data which showed that local efficacy is correlated to tumour absorbed dose, and that the mean absorbed dose is a toxicity risk factor. A pitfall of the crudest, empirical tumour involvement method are 20 deaths in a single centre which adopted it to administer the whole liver, or the need of systematic 25% subjective reduction of activity prescribed with body surface area method. In order to develop a possibly safer and more effective strategy based on real individual dosimetry, we examine first external beam liver radiation therapy results. The half century experience has something to be borrowed: the volume effect, according to which the smaller the fraction of the irradiated liver volume, the higher the tolerated dose. Different tolerance for different underlying disease or previous non radiation treatment is to be expected. Radiobiological models experience also has to be inherited, but not their dose reference values. Then we report the published dosimetric experience about (90)Y microsphere radioembolization of primary and metastatic liver tumours. In addition we also present original data from our growing preliminary experience of more refined (99m)Tc MAA SPECT based calculations in hepatocarcinoma patients. This overcame the mean dose approach in favour of the evaluation of dose distribution at voxel level. An insight into dosimetry issues at microscopic level (lobule level) is also provided, from which the different radiobiological behaviour between resin and glass spheres can be understood. For tumour treatment, an attenuation corrected (99m)Tc- SPECT based treatment planning strategy can be proposed, although quantitative efficacy thresholds should be differentiated according to the kind of pathology and previous treatment. For non tumour liver parenchyma, data in favour of a relationship between absorbed dose and dangerous effects are encouraging. Unfortunately in hepato-cellular carcinoma, some confounding factors may hamper the adequate estimation of the risk of toxicity. First there is a lack of consensus about the exact definition of toxicity after (90)Y microsphere radioembolization. Second, for HCC patients, progression of both cancer and cirrhosis can simulate a radioinduced toxicity, making the analysis more complex.
Backgroun d & Aims : The efficacy of sorafenib in the post-liver transplan tation (LT) setting has been scarcely studied. The aim of this study was to evaluate the efficacy of sorafenib, compared to best suppor tive care (BSC), in two cohorts of patients which presented with hepatocell ular carcinoma (HCC) recurrence after LT. Methods: Data from patients who developed presentat ion or progression of HCC recurrence after LT not amenabl e to surgic al/ locoregio nal treatmen ts (untreatable presentat ion/progress ion, UP) were retrieved. The cohort of patients receivi ng sorafenib starting from 2007 was compared to that of patients receiving BSC in the previous era. Disease outcome was investigat ed in terms of survival from recurre nce or from UP by means of univariate and multiv ariate Cox regression models with event times left-truncat ed at the date of UP. Results: Of a total of 39 patients, 24 received BSC and 15 sorafenib. The two groups were well matched at baseline, with timerelated imbalanc es regarding mTOR-based immun osuppression and median time from LT to recurrence, significantly higher in the sorafenib group. Patients ’ outcome in the sorafenib group was significantly improved (median survival from recurren ce 21.3 vs.11.8 months, HR = 5.2, p = 0.0009; median survival from UP 10.6 vs. 2.2 months, HR = 21.1, p <0.0001). The only factor associated with survival after HCC recurren ce in multivar iate analysis was treatment with sorafenib (HR = 4.0; p = 0.0325). No severe adverse event was registered in this post-LT setting. Conclus ions : Although the use of historical controls weakens final interpreta tion, sorafenib seems to be associ ated with an acceptable safety profile and benefit in surviva l in HCC patients suffering recurren ce after LT. 2013 Europea n Associat ion for the Study of the Liver. Published
The advent of molecular medicine that targets specific pathways is changing the therapeutic approach to hepatocellular carcinoma. For several aberrantly activated pathways in hepatocarcinoma, surrogate markers of activation can be assessed by immunohistochemistry, although associations with in vivo response to targeted therapies are still lacking.A patient, who presented with hepatic and extra-hepatic hepatocarcinoma recurrence 11 years after liver transplantation, was assessed for beta-catenin, pERK, and pS6 in primary and secondary tumor specimens, in order to define a possible activation of the Wnt, Ras/MAPK and Akt/mTOR pathways and design a personalized targeted therapy in absence of alternative treatment options. Moreover, mutation analysis of the beta-catenin gene (CTNNB1) and DNA microsatellite analyses were performed.The identification of the same mutation in the beta-catenin gene, as well as the same microsatellite pattern in tumor tissues taken 11 years apart, proved that the observed hepatocarcinoma was a true recurrence. Nuclear beta-catenin and pS6 in tumor cells were positive, whereas pERK was positive only in the peritumoral endothelium. This pattern of immunohistochemistry, after failure of sorafenib alone, lead to the choice to add the mTOR inhibitor, everolimus, to sorafenib. Three months later a 50% tumor reduction was observed, and after 6 months a further reduction of tumor vital components was confirmed, while a grade II gastrointestinal bleeding episode occurred.A personalized approach aimed to treat recurrent hepatocarcinoma is possible through analysis of tumoral molecular pathways. Partial success of the selected combination of sorafenib and everolimus supports the pivotal role of mTOR signalling and highlights the importance of reliable biomarkers to route the best molecular-based therapeutic options in HCC.
Trans-arterial radioembolization (TARE) is a recognized, although not explicitly recommended, experimental therapy for unresectable hepatocellular carcinoma (HCC).A systematic literature review was performed to identify published studies on the use of TARE in intermediate and advanced stages HCC exploring the efficacy and safety of this innovative treatment.Twenty-one studies reporting data on overall survival (OS) and time to progression (TTP), were included in a meta-analysis. The pooled post-TARE OS was 63% (95% CI: 56-70%) and 27% (95% CI: 21-33%) at 1- and 3-years respectively in intermediate stage HCC, whereas OS was 37% (95% CI: 26-50%) and 13% (95% CI: 9-18%) at the same time intervals in patients with sufficient liver function (Child-Pugh A-B7) but with an advanced HCC because of the presence of portal vein thrombosis. When an intermediate and advanced case-mix was considered, OS was 58% (95% CI: 48-67%) and 17% (95% CI: 12-23%) at 1- and 3-years respectively. As for TTP, only four studies reported data: the observed progression probability was 56% (95% CI: 41-70%) and 73% (95% CI: 56-87%) at 1 and 2 years respectively. The safety analysis, focused on the risk of liver decompensation after TARE, revealed a great variability, from 0-1% to more than 36% events, influenced by the number of procedures, patient Child-Pugh stage and treatment duration.Evidence supporting the use of radioembolization in HCC is mainly based on retrospective and prospective cohort studies. Based on this evidence, until the results of the ongoing randomized trials become available, radioembolization appears to be a viable treatment option for intermediate-advanced stage HCC.
