Rate of local tumor progression following radiofrequency ablation of pathologically early hepatocellular carcinoma

AIM To evaluate whether pathologically early hepatocellular carcinoma(HCC) exhibited local tumor progression after radiofrequency ablation(RFA) less often than typical HCC.METHODS Fifty pathologically early HCCs [tumor diameter(mm): mean, 15.8; range, 10-23; follow-up days after RFA: median, 1213; range, 216-2137] and 187 typical HCCs [tumor diameter(mm): mean, 15.6; range, 6-30; follow-up days after RFA: median, 1116; range, 190-2328] were enrolled in this retrospective study. The presence of stromal invasion(namely, tumor cell invasion into the intratumoral portal tracts) was considered to be the most important pathologic finding for the diagnosis of early HCCs. Typical HCC was defined as the presence of a hyper-vascular lesion accompanied by delayed washout using contrastenhanced computed tomography or contrast-enhanced magnetic resonance imaging. Follow-up examinations were performed at 3-mo intervals to monitor for signs of local tumor progression. The local tumor progression rates of pathologically early HCCs and typical HCCs were then determined using the Kaplan-Meier method.RESULTS During the follow-up period for the 50 pathologically early HCCs, 49(98%) of the nodules did not exhibit local tumor progression. However, 1 nodule(2%) was associated with a local tumor progression found 636 d after RFA. For the 187 typical HCCs, 46(24.6%) of the nodules exhibited local recurrence after RFA. The follow-up period until the local tumor progression of typical HCC was a median of 605 d, ranging from 181 to 1741 d. Among the cases with typical HCCs, local tumor progression had occurred in 7.0%(7/187), 16.0%(30/187), 21.9%(41/187) and 24.6%(46/187) of the cases at 1, 2, 3 and 4 years, respectively. Pathologically early HCC was statistically associated with a lower rate of local tumor progression, compared with typical HCC, when evaluated using a log-rank test(P = 0.002). CONCLUSION The rate of local tumor progression for pathologically early HCCs after RFA was significantly lower than that for typical HCCs.

Stability analysis of slope in strain-softening soils using local arc-length solution scheme

Soils with strain-softening behavior — manifesting as a reduction of strength with increasing plastic strain — are commonly found in the natural environment. For slopes in these soils,a progressive failure mechanism can occur due to a reduction of strength with increasing strain. Finite element method based numerical approaches have been widely performed for simulating such failure mechanism,owning to their ability for tracing the formation and development of the localized shear strain. However,the reliability of the currently used approaches are often affected by poor convergence or significant mesh-dependency,and their applicability is limited by the use of complicated soil models. This paper aims to overcome these limitations by developing a finite element approach using a local arc-length controlled iterative algorithm as the solution strategy. In the proposed finite element approach,the soils are simulated with an elastoplastic constitutive model in conjunction with the Mohr-Coulomb yield function. The strain-softening behavior is represented by a piece-wise linearrelationship between the Mohr-Coulomb strength parameters and the deviatoric plastic strain. To assess the reliability of the proposed finite element approach,comparisons of the numerical solutions obtained by different finite element methods and meshes with various qualities are presented. Moreover,a landslide triggered by excavation in a real expressway construction project is analyzed by the presented finite element approach to demonstrate its applicability for practical engineering problems.

The use of localized proteomics to identify the drivers of Alzheimer's disease pathogenesis

Alzheimer’s disease（AD）is broadly defined by dementia and the presence of specific neuropathological features in the brain（amyloid plaques,neurofibrillary tangles（NFTs）and congophilic amyloid angiopathy）.However,the rate of disease progression,type of cognitive impairment,and extent of neuropathology vary widely in patients with AD（Murray et al.,2011）.

Oncological outcomes and predictors of radiofrequency ablation of colorectal cancer liver metastases

BACKGROUND Surgical resection is considered the standard treatment option for long-term survival in colorectal cancer liver metastasis(CRLM)patients,but only a small number of patients are suitable for resection following diagnosis.Radiofrequency ablation(RFA)is an accepted alternative therapy for CRLM patients who are not suitable for resection.However,the relatively high rate of local tumor progression(LTP)is an obstacle to the more widespread use of RFA.AIM To determine the oncological outcomes and predictors of RFA in CRLM patients.METHODS A retrospective analyze was performed on the clinical data of 85 consecutive CRLM patients with a combined total of 138 liver metastases,who had received percutaneous RFA treatment at our institution from January 2013 to December 2018.Contrast-enhanced computed tomography was performed the first month after RFA to assess the technique effectiveness of the RFA and to serve as a baseline for subsequent evaluations.The Kaplan-Meier method was used to calculate overall survival(OS)and LTP-free survival(LTPFS).The log-rank test and Cox regression model were used for univariate and multivariate analyses to determine the predictors of the oncological outcomes.RESULTS There were no RFA procedure-related deaths,and the technique effectiveness of the treatment was 89.1%(123/138).The median follow-up time was 30 mo.The LTP rate was 32.6%(45/138),and the median OS was 36 mo.The 1-,3-,and 5-year OS rates were 90.6%,45.6%,and 22.9%,respectively.Univariate analysis revealed that tumor size and ablative margin were the factors influencing LTPFS,while extrahepatic disease(EHD),tumor number,and tumor size were the factors influencing OS.Multivariate analysis showed that tumor size larger than 3 cm and ablative margin of 5 mm or smaller were the independent predictors of shorter LTPFS,while tumor number greater than 1,size larger than 3 cm,and presence of EHD were the independent predictors of shorter OS.CONCLUSION RFA is a safe and effective treatment method for CRLM.Tumor size and ablative margin are the important factors affecting LTPFS.Tumor number,tumor size,and EHD are also critical factors for OS.

Efficacy and safety of computed tomography-guided microwave ablation with fine needle-assisted puncture positioning technique for hepatocellular carcinoma

BACKGROUND In microwave ablation(MWA), although computed tomography(CT) scanning can overcome gas interference, it cannot achieve real-time localization. Therefore, the puncture technique is more important in CT-guided ablation.AIM To compare the fine needle-assisted puncture(FNP) positioning technique and the conventional puncture(CP) technique for the safety and efficacy of CT-guided MWA in treating hepatocellular carcinoma(HCC).METHODS This retrospective study included 124 patients with 166 tumor nodules from February 2018 and June 2021. Seventy patients received CT-guided MWA under the FNP technique(FNP group), and 54 patients received MWA under the CP technique(CP group). Intergroup comparisons were made regarding local tumor progression(LTP), recurrence-free survival(RFS), overall survival(OS), and complications. The influencing variables of LTP and RFS were analyzed through univariate and multivariate regressions.RESULTS The 1-, 2-, and 3-year cumulative incidences of LTP in the FNP group were significantly lower than those in the CP group(7.4%, 12.7%, 21.3% vs 13.7%, 32.9%, 36.4%;P = 0.038). The 1-, 2-, and 3-year RFS rates in the FNP group were significantly higher than those in the CP group(80.6%, 73.3%, 64.0% vs 83.3%,39.4%, and 32.5%, respectively;P = 0.008). The FNP technique independently predicted LTP and RFS. Minor complications in the FNP group were lower than those in the CP group(P < 0.001). The difference in median OS was insignificant between the FNP and CP groups(P = 0.229).CONCLUSION The FNP technique used in CT-guided MWA may improve outcomes in terms of LTP, RFS, and procedure-related complications for HCC.