Occurrence,Recurrence Pattern And Long-Term Prognosis Of Microvascular Invasion In Hepatocellular Carcinoma Based On The Barcelomana Clinic Liver Cancer Staging Classification

BACKGROUNDLiver cancer is still one of the most common malignant tumors worldwide.According to the latest cancer statistics,it ranks fourth in incidence and second in mortality in China.Hepatocellular carcinoma(HCC)accounts for more than 80% of liver cancer and is regarded as the most frequent pathological type.In terms of clinical treatment options,the Barcelona Clinic Liver Cancer(BCLC)classification is still the most mainstream treatment staging in the world.However,in recent years,increased studies challenged the reliability and rationality of the BCLC staging with its judgment of prognosis among different stage patients under corresponding treatment.To some extent,depending solely on the tumor size,tumor number,and basic liver function to determine whether patients are suitable for operation,the BCLC staging has been obsolete.When it comes to rational treatment options,the biological behavioral characteristics of HCC are "storm eyes" that really determine the long-term survival outcome under different interventions.Pathological morphology is precisely its most fundamental reference.Therefore,it is possible to adopt a predictable and reasonable intervention method according to the corresponding histomorphological characteristics of HCC,which may be the cornerstone of the future revision of the treatment strategy for HCC.According to the histopathological characteristics,the most important content is the morphological parameters reflecting the invasion and metastasis of HCC.In addition to the tumor grade and the integrity of the capsule,studies in the past decade gradualy indicated the important prognostic value and clinical significance of microvascular invasion(MVI).MVI is the microscopic appearance of a complete endothelial-enclosed tumor nest.The current view is that the advanced growth mode of HCC gives some highly malignant cells the possibility of forming tumor nests independently,and its vasophilicity provides the opportunity for these cell nests to enter the microvessels near the tumor.Thus MVI constitutes the morphological basis of intrahepatic hematogenous metastasis and early recurrence.However,MVI has not received due attention in the real world pathological examination.The most intuitive reflection is that most clinical staging of HCC and guidelines in Europe and the United States do not take MVI as a core parameter for prognosis reference and biological behavior judgment.In this regard,China is at the forefront.Practice guidelines for the pathological diagnosis of primary liver cancer: 2015 update,developed by the Department of Pathology,Eastern Hepatobiliary Surgery Hospital,incorporates MVI into routine diagnostic work,and puts forward the staging criteria of MVI under the 7-point baseline sampling protocol,which provides more valuable message for individualized and accurate clinical diagnosis and treatment.In the context of these premises,we think it is still necessary to explore:(1)the incidence rate of MVI under the standard sampling protocol;(2)the prognostic value of Chinese staging of MVI;(3)the effects of MVI on recurrence and prognosis in different BCLC stages;Can MVI indicate the biological behavioral reason of controversy over treatment options?(4)Are there reasonable interventions for patients with the presence of MVI to reduce the high recurrence rate and improve long-term survival?METHODSWe retrospectively followed patients with single nodular HCC(BCLC stage 0,≤2 cm)who underwent curative hepatectomy from January 1,2010 to December 31,2012,patients with primary HCC(BCLC stage 0,stage A,stage B)who underwent curative hepatectomy from December 1,2009 to December 31,2010,and patients with multinodular HCC(BCLC stage A4;≤3 nodules,each ≤3 cm)who underwent radical hepatectomy from January 1,2010 to December 31,2014.The clinicopathological data and prognostic information were obtained.Recurrence-free survival and overall survival were the end points of the study.Kaplan-Meier method was performed to compare the survival of different groups.Cox proportional hazards model was used to explore survival-related risk factors,Logistic regression was conducted to explore variables related factors,and propensity score matching is employed to balance differences between groups and reduce bias.RESULTS1.Different with the eighth edition of TNM staging,we believe that MVI is still an important risk factor for single nodular HCC up to 2 cm.2.In multinodular HCC of the BCLC stage A,the prognosis of patients with the presence of MVI is worse than that of patients with single nodular HCC,but the prognosis of patients with the absence of MVI is not significantly different from that of patients with single nodular HCC.Therefore,from the perspective of biological behavior,BCLC stage A multinodular HCC patients with MVI should not be divided into early stage.3.Adjuvant transcatheter arterial chemoembolization can reduce the recurrence rate of multinodular HCC within the BCLC stage A.4.Unlike previous studies,we think that MVI is still an important predictor of poor prognosis of HCC within the BCLC stage B,and highly suggests the possibility of early intrahepatic metastatic recurrence after operation.CONCLUSIONMVI is highly suggestive of early recurrence and adverse prognosis of HCC within different stages;MVI was potential to be an important pathological parameter to distinguish early or advanced stage HCC in the sense of biological behavior;adjuvant transcatheter arterial chemoembolization is an acceptable post-operative anti-recurrence therapy for some patients with the presence of MVI.