Optimal proximal resection margin distance for gastrectomy in advanced gastric cancer

BACKGROUND The conventional guidelines to obtain a safe proximal resection margin(PRM)of5-6 cm during advanced gastric cancer(AGC)surgery are still applied by many surgeons across the world.Several recent studies have raised questions regarding the need for such extensive resection,but without reaching consensus.This study was designed to prove that the PRM distance does not affect the prognosis of patients who undergo gastrectomy for AGC.AIM To investigate the influence of the PRM distance on the prognosis of patients who underwent gastrectomy for AGC.METHODS Electronic medical records of 1518 patients who underwent curative gastrectomy for AGC between June 2004 and December 2007 at Asan Medical Center,a tertiary care center in Korea,were reviewed retrospectively for the study.The demographics and clinicopathologic outcomes were compared between patients who underwent surgery with different PRM distances using one-way ANOVA and Fisher’s exact test for continuous and categorical variables,respectively.The influence of PRM on recurrence-free survival and overall survival were analyzed using Kaplan-Meier survival analysis and Cox proportional hazard analysis.RESULTS The median PRM distance was 4.8 cm and 3.5 cm in the distal gastrectomy(DG)and total gastrectomy(TG)groups,respectively.Patient cohorts in the DG and TG groups were subdivided into different groups according to the PRM distance;≤1.0 cm,1.1-3.0 cm,3.1-5.0 cm and>5.0 cm.The DG and TG groups showed nostatistical difference in recurrence rate(23.5%vs 30.6%vs 24.0%vs 24.7%,P=0.765)or local recurrence rate(5.9%vs 6.5%vs 8.4%vs 6.2%,P=0.727)according to the distance of PRM.In both groups,Kalpan-Meier analysis showed no statistical difference in recurrence-free survival(P=0.467 in DG group;P=0.155 in TG group)or overall survival(P=0.503 in DG group;P=0.155 in TG group)according to the PRM distance.Multivariate analysis using Cox proportional hazard model revealed that in both groups,there was no significant difference in recurrence-free survival according to the PRM distance.CONCLUSION The distance of PRM is not a prognostic factor for patients who undergo curative gastrectomy for AGC.

Genomics of plant speciation

Studies of plants have been instrumental for revealing how new species originate.For several decades,botanical research has complemented and,in some cases,challenged concepts on speciation developed via the study of other organisms while also revealing additional ways in which species can form.Now,the ability to sequence genomes at an unprecedented pace and scale has allowed biologists to settle decades-long debates and tackle other emerging challenges in speciation research.Here,we review these recent genome-enabled developments in plant speciation.We discuss complications related to identification of reproductive isolation(RI)loci using analyses of the landscape of genomic divergence and highlight the important role that structural variants have in speciation,as increasingly revealed by new sequencing technologies.Further,we review how genomics has advanced what we know of some routes to new species formation,like hybridization or whole-genome duplication,while casting doubt on others,like population bottlenecks and genetic drift.While genomics can fast-track identification of genes and mutations that confer RI,we emphasize that follow-up molecular and field experiments remain critical.Nonetheless,genomics has clarified the outsized role of ancient variants rather than new mutations,particularly early during speciation.We conclude by highlighting promising avenues of future study.These include expanding what we know so far about the role of epigenetic and structural changes during speciation,broadening the scope and taxonomic breadth of plant speciation genomics studies,and synthesizing information from extensive genomic data that have already been generated by the plant speciation community.

腹腔镜胃癌手术的历史与展望

胃恶性肿瘤是全世界常见且致命的恶性肿瘤之一。根据2012年数据,胃癌居全世界恶性肿瘤发病率第5位,肿瘤相关病死率第3位。胃癌是严重危及人民健康的疾病之一。腹腔镜手术不仅将手术创伤最小化,且在降低手术并发症的同时加速患者康复。因此,该技术在外科领域已逐渐取代开腹手术。笔者分析腹腔镜胃癌手术相关前瞻性、随机性研究等相关文献,结合自身临床经验及最新见解,就腹腔镜胃癌手术的历史、现状及发展趋势进行深入阐述。

Recurrence of hepatocellular carcinoma following deceased donor liver transplantation:case series

Aim:We aimed to study the clinical and pathological characteristics of liver transplant recipients with hepatocellular carcinoma recurrence.Methods:We reviewed the data for 26 patients who had tumor recurrence after deceased donor liver transplant for hepatocellular carcinoma at the Johns Hopkins Hospital from January 2005 to December 2015.Results:In total,88%of recipients were males.The mean age was 59 years.On explant,poor differentiation was detected in 43%,while 73%had microvascular invasion.Overall,62%were diagnosed to be outside of Milan criteria.Out of these,15%met the criteria for downstaging.Twenty(77%)patients had pre-transplant alpha fetoprotein levels≥20 ng/mL.In 54%of patients,the location of hepatocellular carcinoma(HCC)recurrence was extrahepatic,followed by intrahepatic in 31%and both intra-and extrahepatic in 15%.The post-transplant tumor recurrence was diagnosed at a mean of 427 days(range 34-1502).Fifty percent of HCC recurrences were diagnosed within one year following liver transplant.Twenty(77%)patients received treatment for their recurrent HCC:external radiation(n=10),surgical resections(n=8;brain 4,spine 2,bone 1,and Whipple surgery 1),sorafenib(n=7),locoregional therapy(n=5).Overall,24 out of 26(92%)recipients died within four years after the transplant.Conclusion:HCC recurrence after liver transplant is infrequent.More than fifty percent of HCC recurrences following liver transplant are extrahepatic.Despite better recipient selection for liver transplant,the curative options are limited in recurrent cases and associated with extremely poor outcomes.