Influence of donor age on liver transplantation outcomes: A multivariate analysis and comparative study

BACKGROUND The growing disparity between the rising demand for liver transplantation(LT)and the limited availability of donor organs has prompted a greater reliance on older liver grafts.Traditionally,utilizing livers from elderly donors has been associated with outcomes inferior to those achieved with grafts from younger donors.By accounting for additional risk factors,we hypothesize that the utili-zation of older liver grafts has a relatively minor impact on both patient survival and graft viability.AIM To evaluate the impact of donor age on LT outcomes using multivariate analysis and comparing young and elderly donor groups.METHODS In the period from April 2013 to December 2018,656 adult liver transplants were performed at the University Hospital Merkur.Several multivariate Cox propor-tional hazards models were developed to independently assess the significance of donor age.Donor age was treated as a continuous variable.The approach involved univariate and multivariate analysis,including variable selection and assessment of interactions and transformations.Additionally,to exemplify the similarity of using young and old donor liver grafts,the group of 87 recipients of elderly donor liver grafts(≥75 years)was compared to a group of 124 recipients of young liver grafts(≤45 years)from the dataset.Survival rates of the two groups were estimated using the Kaplan-Meier method and the log-rank test was used to test the differences between groups.RESULTS Using multivariate Cox analysis,we found no statistical significance in the role of donor age within the constructed models.Even when retained during the entire model development,the donor age's impact on survival remained insignificant and transformations and interactions yielded no substantial effects on survival.Consistent insigni-ficance and low coefficient values suggest that donor age does not impact patient survival in our dataset.Notably,there was no statistical evidence that the five developed models did not adhere to the proportional hazards assumption.When comparing donor age groups,transplantation using elderly grafts showed similar early graft function,similar graft(P=0.92),and patient survival rates(P=0.86),and no significant difference in the incidence of postoperative complications.CONCLUSION Our center's experience indicates that donor age does not play a significant role in patient survival,with elderly livers performing comparably to younger grafts when accounting for other risk factors.

Efficacy evaluation and survival analysis of the combination of oxaliplatin plus Teysuno (SOX) with immune checkpoint inhibitors in the conversion therapy of locally advanced gastric cancer

Background:The efficacy of combining immune checkpoint inhibitors(ICIs)with chemotherapy in neoadjuvant therapy for locally advanced gastric cancer has been explored.However,limited research exists on its effectiveness in conversion therapy,and its superiority over standalone chemotherapy remains to be elucidated.This study aims to investigate the efficacy and survival outcomes of patients treated with ICIs in combination with conversion therapy for locally advanced gastric cancer.Methods:Retrospective data from patients with locally advanced gastric cancer treated with either oxaliplatin+S-1(SOX)alone or in combination with ICIs in conversion therapywere collected.Clinical andpathological characteristics,disease-free survival,andefficacy assessments in nonoperable patients were compared between the 2 treatment groups.Efficacy was further evaluated through dynamic changes in serum markers,and patients’quality of life was assessed using the QLQ-STO22(Gastric Cancer–Specific Quality of Life Questionnaire)quality-of-life measurement scale.Results:A total of 140 patients underwent conversion therapy:80 in the SOX alone group and 60 in the SOX combined with the ICIs group.There were no significant differences in baseline characteristics between the 2 groups.Compared with the SOX alone group,the SOX combined with ICIs group exhibited a higher conversion rate(83.3%vs 75%,P=0.23),R0 resection rate(90.0%vs 83.3%,P=0.31),pathological complete response(pCR)rate(18%vs 5%,P=0.02),median disease-free survival(21.4 vs 16.9 months,P=0.007),the objective response rate in nonoperable patients(60%vs 40%,P=0.301),and median progression-free survival time(7.9 vs 5.7 months,P=0.009).The QLQ-STO22 quality-of-life assessment revealed statistically significant improvements in pain,swallowing difficulties,and dietary restrictions in the combination therapy group compared with those in the monotherapy group.The enhanced efficacy of immune combination with SOX is evident,as demonstrated by the significantly prolonged surgical duration in operated patients(206.6±26.6 min vs 197.8±19.8 min,P=0.35)and intraoperative blood loss(158.9±21.2 mL vs 148.9±25.1 mL,P=0.59).No significant differences were observed in postoperative complications.Conclusions:Compared with the SOX conversion therapy regimen,SOX combined with ICIs demonstrated higher conversion rates,R0 resection rates,pathological response rates,and disease-free survival without increasing surgical difficulty or complications.Nonoperable patients also experienced longer progression-free survival and objective response rates.

Clinicopathological features and survival analysis of gastroenteropancreatic neuroendocrine neoplasms: a retrospective study in a single center of China

Objective： To investigate the clinicopathological features, survival and prognostic factors for gastroenteropancreatic neuroendocrine neoplasms（GEP-NENs） in a Chinese population.Methods： We investigated 154 consecutive patients（88 males, 66 females; median age 56 years, age range 9-86 years） diagnosed with GEP-NENs between 2001 and 2013 at The Affiliated Hospital of Qingdao University. Demographic, clinical and pathological variables and survival data were retrieved.Results： The pancreas was the most common site of involvement（63/154, 40.9%）. Tumor size varied from 0.3 to 16.0 cm（median, 1.2 cm）. The patients were followed up for a median period of 22 months（range, 1-157 months）. The estimated 3- and 5-year overall survival（OS） rates for all patients were 84.0% and 81.9%, respectively. Multivariate analysis showed that larger tumor size, lymphatic metastases and distant metastases were significant predictors for poor survival outcome.Conclusions： Our data provide further information on the clinicopathological features of GEP-NENs in China. Additionally, we identified tumor size, lymphatic metastases and distant metastases as independent prognostic factors for long-term survival.

Characteristics and dynamics analysis of Populus euphratica populations in the middle reaches of Tarim River

Populus euphratica Oliv. is widely distributed along the Tarim River. Maintaining stability of P. euphratica population is important to local development. This study explored the static life table, survivorship curves and four function curves (survival rate, cumulative mortality rate, mortality density, and hazard rate), and development index of P. euphratica population in the middle reaches of Tarim River. The results indicated that the age structure of P. euphratica population belonged to positive pyramidal type, which meant young age-class individuals occupied most populations. The number ofⅠ-Ⅱage classes accounted for 66.2% of whole population, and this indicated that there were abundant subsequent seedlings resources to support the growth of P. euphratica population in the middle reaches of Tarim River. The survivorship curve of P. euphratica belonged to the Deevey Ⅲ (concave-type) and the development index was 47.72%. Four function curves revealed that the individuals of P. euphratica sharply decreased at the initial stage and then leveled off at the late stage of survival curve. Time sequence prediction models predicted that the number of midlife individuals would increase in future 10, 20, 30 years, and P. euphratica population grew steadily as a result of rich saplings.

Hepatocellular carcinoma in extremely elderly patients:An analysis of clinical characteristics,prognosis and patient survival

AIM： To identify the clinical and prognostic features of patients with hepatocellular carcinoma （HCC） aged 80 years or more. METHODS： A total of 1310 patients with HCC were included in this study. Ninety-one patients aged 80 years or more at the time of diagnosis of HCC were defined as the extremely elderly group. Two hundred and thirty-four patients aged 〉/ 50 years but less than 60 years were regarded as the non-elderly group. RESULTS： The sex ratio （male to female） was significantly lower in the extremely elderly group （0.90：1） than in the non-elderly group （3.9：1, P〈 0.001）. The positive rate for HBsAg was significantly lower in the extremely elderly group and the proportion of patients negative for HBsAg and HCVAb obviously increased in the extremely elderly group （P〈 0.001）. There were no significant differences in the following parameters： diameter and number of tumors, Child-Pugh grading, tumor staging, presence of portal thrombosis or ascites, and positive rate for HCVAb. Extremely elderly patients did not often receive surgical treatment （P 〈 0.001） and they were more likely to receive conservative treatment （P〈 0.01）. There were no significant differences in survival curves based on the Kaplan-Meier methods in comparison with the overall patients between the two groups. However, the survival curves were significantly worse in the extremely elderly patients with stage Ⅰ/Ⅱ, stage Ⅰ/Ⅱ and Child-Pugh grade A cirrhosis in comparison with the non-elderly group. The causes of death did not differ among the patients, and most cases died of liverrelated diseases even in the extremely elderly patients. CONCLUSION： In the patients with good liver functions and good performance status, aggressive treatment for HCC might improve the survival rate, even in extremely elderly patients.

Clinicopathological analysis of paraganglioma with literature review

AIM： To investigate the 152 cases of paragangliomas resected over the past 32 years in West China Hospital dinicopathologically.METHODS： All cases of paragangliomas diagnosed at the Department of Gastrointestinal Surgery and Department of Pathology, West China Hospital, China were reviewed. The pathological documents were supplied by the Department of Pathology, West China Hospital, and other necessary data were extracted from the hospital records. The statistical analyses were performed by survival analysis （Kaplan-Meier method）, descriptive statistical analyses and Х^2 analysis.RESULTS： The neuroendocrine marker vimentin was found to be selectively expressed in the benign tumors, and there were significant differences in the expression of those markers in both benign and malignant tumors. The survival analysis revealed that survival correlated significantly with the malignancy, metastasis and nodal status.CONCLUSION： Vimentin may be useful in the differential diagnosis between malignant and benign tumors. The difference in the expression of this marker in the tumors could be a clue to the future clinical diagnosis. The malignancy, metastasis and the nodal status may predict the prognosis of this disease.

Repeat hepatectomy for recurrent colorectal liver metastases:A comparative analysis of short-and long-term results

Background: Liver recurrence after resection of colorectal liver metastases(CRLM) is frequent. Repeat hepatectomy has been shown to have satisfactory perioperative results. However, the long-term outcomes and the benefts for patients with early recurrence have not been clarifed. The aim of this study was to compare the short-and long-term outcomes of patients undergoing single hepatectomy and repeat hepatectomy for CRLM. Additionally, the oncological outcomes of patients with early( ≤ 6 months) and late recurrence who underwent repeat hepatectomy were compared. Methods: Consecutive adult patients undergoing hepatectomy for CRLM between June 20 0 0 and February 2020 were included and divided into two groups: single hepatectomy and repeat hepatectomy. Results: A total of 709 patients were included: 649 in the single hepatectomy group and 60 in the repeat hepatectomy group. Patients in the repeat hepatectomy group underwent more cycles of preoperative chemotherapy [4(3-6) vs. 3(2-4), P = 0.003]. Patients in the single hepatectomy group more frequently underwent major hepatectomies(34.5% vs. 16.7%, P = 0.004) and had a greater number of lesions resected(2.9 ± 3.6 vs. 1.9 ± 1.8, P = 0.011). There was no increase in operative time, estimated blood loss, length of hospital stay, complications, or mortality in the repeat hepatectomy group. There were no differences in overall survival( P = 0.626) and disease-free survival( P = 0.579) between the two groups. Similarly, for patients underwent repeat hepatectomy, no difference was observed between the early and late recurrence groups in terms of overall survival( P = 0.771) or disease-free survival( P = 0.350). Conclusions: Repeat hepatectomy is feasible and safe, with similar short-and long-term outcomes when compared to single hepatectomy. Surgical treatment of early liver recurrence offers similar oncological outcomes to those obtained for late recurrence.

Survival analysis following early surgical success in intermittent exotropia surgery

AIM:To assess the consecutive recurrence following early success of intermittent exotropia surgery and to determine the clinical factors that affect the survival.METHODS:One hundred and thirty-five patients who underwent intermittent exotropia surgery and experienced early surgical success[≤5 prism diopters(PD)esophoria(E)to≤10 PD exophoria(X)on the postoperative sixth month]were enrolled in this study.Their consecutive survival on the postoperative first year,second year and third year and at the last visit of fourth year or more,and the factors that might affect their survival,were analyzed.The final surgical outcomes after the postoperative fourth year were also investigated by dividing the patients into the success group(≤5 PD E to≤10 PD X)and the failure group(】5 PD esodeviation or】10 PD exodeviation)RESULTS:The survival rates from the Kaplan-Meier analysis were 97.78%,92.89%,83.70%and 50.49%on the postoperative first,second and third years and fourth year or more,respectively.None of the clinical factors was determined to have affected the survival.The amount of the exodrift was largest(2.29 PD)between the first year and the second year,and smallest(1.47 PD)between the fourth year and the last visit.Sixty-three patients had their final visit after the postoperative fourth year,and 29 of them were in the failure group.Twentyfive patients in the failure group had an intermittent exotropia(IXT)of【20 PD with good to fair distant fusion;two had an IXT of【20 PD with poor distant fusion;one had an IXT of≥20 PD with fair distant fusion;and another had delayed-onset consecutive esotropia.The exodeviation on the postoperative sixth month was smaller in the success group than in the failure group(2.81 PD vs 5.86 PD,P=0.012).The reoperation rate for recurrent IXT was 3.7%.CONCLUSION:The survival rate steadily decreases with the exodrift,but the amount of the exodrift decreases with long-term follow-up.The final outcomes demonstrate favorable results via surgical success or small-angle IXT with good fusion in most of the patients.A smaller deviation on the postoperative sixth month is associated with long-term survival.

Paclitaxel-etoposide-carboplatin/cisplatin versus etoposidecarboplatin/cisplatin as first-line treatment for combined small-cell lung cancer: a retrospective analysis of 62 cases

Objective: To compare the efficacy and adverse effects of paclitaxel-etoposide-carboplatin/cisplatin(TEP/TCE) regimen with those of etoposide-carboplatin/cisplatin(EP/CE) regimen as first-line treatment for combined small-cell lung cancer(CSCLC).Methods: A retrospective study was conducted on 62 CSCLC patients who were treated at Tianjin Medical University Cancer Institute and Hospital from July 2000 to April 2013 and administered with TEP/TCE regimen(n=19) or EP/CE regimen(n=43) as first-line CSCLC treatment. All patients received more than two cycles of chemotherapy, and the response was evaluated every two cycles. The primary endpoint was overall survival(OS), and the secondary endpoints were progression-free survival(PFS), objective response rate(ORR), disease control rate(DCR), and adverse effects. Results: ORR between the TEP/TCE and EP/CE groups showed a statistical difference(90% vs. 53%, P=0.033). Both groups failed to reach a statistical difference in DCR(100% vs. 86%, P=0.212). The median PFS and OS of the TEP/TCE group were slightly longer than those of the EP/CE group, although both groups failed to reach a statistical difference(10.5 vs. 8.9 months, P=0.484; 24.0 vs. 17.5 months, P=0.457). However, stratified analysis indicated that the PFS of patients with stages III and IV CSCLC showed marginally significant difference between the TEP/TCE and EP/CE groups(19.5 vs. 7.6 months; P=0.071). Both rates of grade IV bone marrow depression and termination of chemotherapy in the TEP/TCE group were significantly higher than those in the EP/CE group(26.3% vs. 7.0%, P=0.036; 31.6% vs. 14.7%, P=0.004). Conclusion: The TEP/TCE regimen may not be preferred for CSCLC, and this three-drug regimen requires further exploration and research. To date, the EP/CE regimen remains the standard treatment for CSCLC patients.

Factors Predicting Progression to Severe COVID-19: A Competing Risk Survival Analysis of 1753 Patients in Community Isolation in Wuhan, China

Most studies of coronavirus disease 2019(COVID-19)progression have focused on the transfer of patients within secondary or tertiary care hospitals from regular wards to intensive care units.Little is known about the risk factors predicting the progression to severe COVID-19 among patients in community iso-lation,who are either asymptomatic or suffer from only mild to moderate symptoms.Using a multivari-able competing risk survival analysis,we identify several important predictors of progression to severe COVID-19—rather than to recovery—among patients in the largest community isolation center in Wuhan,China from 6 February 2020(when the center opened)to 9 March 2020(when it closed).All patients in community isolation in Wuhan were either asymptomatic or suffered from mild to moderate COVID-19 symptoms.We performed competing risk survival analysis on time-to-event data from a cohort study of all COVID-19 patients(n=1753)in the isolation center.The potential predictors we inves-tigated were the routine patient data collected upon admission to the isolation center:age,sex,respira-tory symptoms,gastrointestinal symptoms,general symptoms,and computed tomography(CT)scan signs.The main outcomes were time to severe COVID-19 or recovery.The factors predicting progression to severe COVID-19 were:male sex(hazard ratio(HR)=1.29,95%confidence interval(CI)1.04–1.58,p=0.018),young and old age,dyspnea(HR=1.58,95%CI 1.24–2.01,p<0.001),and CT signs of ground-glass opacity(HR=1.39,95%CI 1.04–1.86,p=0.024)and infiltrating shadows(HR=1.84,95%CI 1.22–2.78,p=0.004).The risk of progression was found to be lower among patients with nausea or vomiting(HR=0.53,95%CI 0.30–0.96,p=0.036)and headaches(HR=0.54,95%CI 0.29–0.99,p=0.046).Our results suggest that several factors that can be easily measured even in resource-poor set-tings(dyspnea,sex,and age)can be used to identify mild COVID-19 patients who are at increased risk of disease progression.Looking for CT signs of ground-glass opacity and infiltrating shadows may be an affordable option to support triage decisions in resource-rich settings.Common and unspecific symptoms(headaches,nausea,and vomiting)are likely to have led to the identification and subsequent community isolation of COVID-19 patients who were relatively unlikely to deteriorate.Future public health and clinical guidelines should build on this evidence to improve the screening,triage,and monitoring of COVID-19 patients who are asymtomatic or suffer from mild to moderate symptoms.

Comparison of Cox proportional hazards model,Cox proportional hazards with time-varying coefficients model,and lognormal accelerated failure time model:Application in time to event analysis of melioidosis patients

Objective:To compare the prognostic factors of mortality among melioidosis patients between lognormal accelerated failure time(AFT),Cox proportional hazards(PH),and Cox PH with time-varying coefficient(TVC)models.Methods:A retrospective study was conducted from 2014 to 2019 among 453 patients who were admitted to Hospital Sultanah Bahiyah,Kedah and Hospital Tuanku Fauziah,Perlis in Northern Malaysia due to confirmed-cultured melioidosis.The prognostic factors of mortality from melioidosis were obtained from AFT survival analysis,and Cox’s models and the findings were compared by using the goodness of fit methods.The analyses were done by using Stata SE version 14.0.Results:A total of 242 patients(53.4%)survived.In this study,the median survival time of melioidosis patients was 30.0 days(95%CI 0.0-60.9).Six significant prognostic factors were identified in the Cox PH model and Cox PH-TVC model.In AFT survival analysis,a total of seven significant prognostic factors were identified.The results were found to be only a slight difference between the identified prognostic factors among the models.AFT survival showed better results compared to Cox's models,with the lowest Akaike information criteria and best fitted Cox-snell residuals.Conclusions:AFT survival analysis provides more reliable results and can be used as an alternative statistical analysis for determining the prognostic factors of mortality in melioidosis patients in certain situations.

Identification of differentially expressed metastatic genes and their signatures to predict the overall survival of uveal melanoma patients by bioinformatics analysis

AIM:To identify metastatic genes and mi RNAs and to investigate the metastatic mechanism of uveal melanoma(UVM).METHODS:GSE27831,GSE39717,and GSE73652 gene expression profiles were downloaded from the Gene Expression Omnibus(GEO)database,and the limma R package was used to identify differentially expressed genes(DEGs).Gene Ontology(GO)term enrichment analysis and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis were performed using the DAVID online tool.A comprehensive list of interacting DEGs was constructed using the Search Tool for the Retrieval of Interacting Genes(STRING)database and Cytoscape software.The Cytoscape MCODE plug-in was used to identify clustered sub-networks and modules of hub genes from the proteinprotein interaction network.GEPIA online software was used for survival analysis of UVM patients(n=80)from the The Cancer Genome Atlas(TCGA)cohort.Oncomi R online software was used to find that the mi RNAs were associated with UVM prognosis from the TCGA cohort.Target Scan Human 7.2 software was then used to identify the mi RNAs targeting the genes.RESULTS:There were 1600 up-regulated genes and 1399 down-regulated genes.The up-regulated genes were mainly involved in protein translation in the cytosol,whereas the down-regulated genes were correlated with extracellular matrix organization and cell adhesion in the extracellular space.Among the 2999 DEGs,five genes,Znf391,Mrps11,Htra3,Sulf2,and Smarcd3 were potential predictors of UVM prognosis.Otherwise,three mi RNAs,hsa-mi R-509-3-5 p,hsa-mi R-513 a-5 p,and hsa-mi R-1269 a were associated with UVM prognosis.CONCLUSION:After analyzing the metastasis-related enriched terms and signaling pathways,the up-regulated DEGs are mainly involved in protein synthesis and cell proliferation by ribosome and mitogen-activated protein kinase(MAPK)pathways.However,the down-regulated DEGs are mainly involved in processes that reduced cell-cell adhesion and promoted cell migration in the extracellular matrix through PI3 K-Akt signaling pathway,focal adhesion,and extracellular matrix-receptor interactions.Bioinformatics and interaction analysis may provide new insights on the events leading up to the development and progression of UVM.

Clinical features and prognostic factors in 49 patients with follicular lymphoma at a single center:A retrospective analysis

BACKGROUND Follicular lymphoma(FL)is a type of B-cell lymphoma that originates at the germinal center and has a low malignancy rate.FL has become the most common inert lymphoma in Europe and America but has a relatively low incidence in Asia.AIM To explore the clinical features,curative effects,and prognostic factors of FL.METHODS Completed medical records of 49 patients with FL who were admitted to the Ningbo First Hospital from June 2010 to June 2021 were examined.These patients were definitively diagnosed by pathological biopsy or immunohistochemical staining.The diagnostic criteria were based on the 2008 World Health Organization classification of lymphomas.Ann Arbor staging was performed according to the imaging and bone marrow examination results.Risk stratification of all patients was performed based on the International Prognostic Index(IPI),age-adjusted IPI,Follicular Lymphoma International Prognosis Index(FLIPI),and FLIPI2 to compare the efficacy of different treatment regimens and analyze the related prognostic factors.RESULTS The age of onset in patients ranged from 24 to 76 years,with a median age of 51 years.Most patients developed the disease at 40–59 years of age,and the male:female ratio was 1.6:1.No significant difference was noted in the curative effect between the non-chemotherapy,combined chemotherapy,and other chemotherapy regimens(P>0.05).Hemoglobin(Hb)level<120 g/L,Ki-67 value>50%,bone marrow involvement,and clinical stagesⅢ–IV were associated with a poor prognosis of FL(P<0.05).However,the influence of other indicators was not statistically significant.Risk grouping was performed using the FLIPI,and the results showed that 24.5%,40.8%,and 34.7%of patients were in the low-,moderate-,and high-risk groups,respectively.According to the survival analysis results,the survival rate of patients was lower in the high-risk group than in the other low-risk and moderate-risk groups(P<0.05).CONCLUSION FL mainly occurs in middle-aged and elderly men,primarily affecting lymph nodes and bone marrow.Hb level,Ki-67 value,bone marrow involvement,and clinical staging were used to evaluate prognosis.

Comprehensive Analysis of Key mRNAs and lncRNAs in Osteosarcoma Response to Preoperative Chemotherapy with Prognostic Values

Objective:Osteosarcoma is one of the most common types of bone sarcoma with a poor prognosis.However,identifying the predictive factors that contribute to the response to neoadjuvant chemotherapy remains a significant challenge.Methods:A public data series(GSE87437)was downloaded to identify differentially expressed genes(DEGs)and differentially expressed lncRNAs(DElncRNAs)between osteosarcoma patients that do and do not respond to preoperative chemotherapy.Subsequently,functional analysis of the transcriptome expression profile,regulatory networks of DEGs and DElncRNAs,competing endogenous RNAs(ceRNA)and protein-protein interaction networks were performed.Furthermore,the function,pathway,and survival analysis of hub genes was performed and drug and disease relationship prediction of DElncRNA was carried out.Results:A total of 626 DEGs,26 DElncRNAs,and 18 hub genes were identified.However,only one gene and two lncRNAs were found to be suitable as candidate gene and lncRNAs respectively.Conclusion:The DEGs,hub genes,candidate gene,and candidate lncRNAs screened out in this context were considered as potential biomarkers for the response to neoadjuvant chemotherapy of osteosarcoma.

High Cycle Fatigue Life Prediction and Reliability Analysis of Aeroengine Blades

Based on the nonlinear continuum damage model （CDM） developed by Chaboehe, a modified model for high cycle fatigue of TC4 alloy was proposed. Unsymmetrical cycle fatigue tests were conducted on rod specimens at room temperature. Then the material parameters needed in the CDM were obtained by the fatigue tests, and the stress distribution of the specimen was calculated by FE method. Compared with the linear damage model （LDM）, the dam- age results and the life prediction of the CDM show a better agreement with the test and they are more precise than the LDM. By applying the CDM developed in this study to the life prediction of aeroengine blades, it is concluded that the root is the most dangerous region of the whole blade and the shortest life is 58 211 cycles. Finally, the Cox propor- tional hazard model of survival analysis was applied to the analysis of the fatigue reliability. The Cox model takes the covariates into consideration, which include diameter, weight, mean stress and tensile strength. The result shows that the mean stress is the only factor that accelerates the fracture process.

Nested case-control analysis with general additive-multiplicative hazard models

This paper discusses the nested case-control analysis under a class of general additive-multiplicative hazard models which includes the Cox model and the additive hazard model as special cases.A pseudo-score is constructed to estimate the regression parameters.The resulting estimator is shown to be consistent and asymptotically normally distributed.The limiting variance-covariance matrix can be consistently estimated by the nested case-control data.A simulation study is conducted to assess the finite sample performance of the proposed estimator and a real example is provided for illustration.

Propensity-matched analysis of patients with intrahepatic cholangiocarcinoma or mixed hepatocellular-cholangiocarcinoma and hepatocellular carcinoma undergoing a liver transplant

BACKGROUND Cholangiocarcinoma(CC)is a rare tumor that arises from the epithelium of the bile ducts.It is classified according to anatomic location as intrahepatic,perihilar,and distal.Intrahepatic CC(ICC)is rare in patients with cirrhosis due to causes other than primary sclerosing cholangitis.Mixed hepatocellular carcinoma-CC(HCC-CC)is a rare neoplasm that shows histologic findings of both HCC and ICC within the same tumor mass.Due to the difficulties in arriving at the correct diagnosis,patients eventually undergo liver transplantation(LT)with a presumptive diagnosis of HCC on imaging when,in fact,they have ICC or HCC-CC.AIM To evaluate the outcomes of patients with intrahepatic cholangiocarcinoma or mixed hepatocellular-cholangiocarcinoma on pathological examination after liver transplant.METHODS Propensity score matching was used to analyze tumor recurrence(TR),overall mortality(OM),and recurrence-free survival(RFS)in LT recipients with pathologically confirmed ICC or HCC-CC matched 1:8 to those with HCC.Progression-free survival and overall mortality rates were computed with the Kaplan-Meier method using Cox regression for comparison.RESULTS Of 475 HCC LT recipients,1.7%had the diagnosis of ICC and 1.5%of HCC-CC on pathological examination of the explant.LT recipients with ICC had higher TR(46%vs 11%;P=0.006),higher OM(63%vs 23%;P=0.002),and lower RFS(38%vs 89%;P=0.002)than those with HCC when matched for pretransplant tumor characteristics,as well as higher TR(46%vs 23%;P=0.083),higher OM(63%vs 35%;P=0.026),and lower RFS(38%vs 59%;P=0.037)when matched for posttransplant tumor characteristics.Two pairings were performed to compare the outcomes of LT recipients with HCC-CC vs HCC.There was no significant difference between the outcomes in either pairing.CONCLUSION Patients with ICC had worse outcomes than patients undergoing LT for HCC.The outcomes of patients with HCC-CC did not differ significantly from those of patients with HCC.

A clinical analysis and prognostic study of 62 cases with T1G3 urothelial carcinoma of the bladder

Objective:The aim of our study was to clarify the clinicopathological factors affecting the outcome of T1G3 urothelial carcinoma of the bladder.Methods:We retrospectively reviewed 62 cases of T1G3 bladder cancer treated with transuretheral resection of bladder toumor (TURBT) followed by intravesical instillation between 1997 and 2009.Cumulative survival was analyzed by Kaplan-Meier method.Cox regression was used for univariate and multivariate analysis.Log-rank method was used for the significance test.The statistical difference was accepted when the P value was lower than 0.05.Results:Median follow-up period was 40 months (6-140 months).Forty-one cases of intravesical recurrence (66%) were observed during follow-up.Two-and 5-year recurrence-free survival rates were 43.4% and 35.1%.Fourteen cases of progression (23%) were observed during the follow-up period.Two-and 5-year progression-free survival rates were 86.4% and 83.5%,respectively.Significant factors for tumor recurrence and progression were analyzed by Cox regression.Tumor multiplicity (RR=2.250),size (RR=1.039) and history of recurrence (RR=2.162) were significantly correlated with recurrence and tumor multiplicity (RR=3.695) was significantly correlated with progression on multivariate analysis.Conclusion:Tumor multiplicity,size,history of recurrence were correlated with recurrence and tumor multiplicity was significantly correlated with progression.Tumor multiplicity,size and history of recurrence should be taken into account when we make therapy strategies for T1G3 urothelial carcinoma of the bladder.

Correction:Propensity-matched analysis of patients with intrahepatic cholangiocarcinoma or mixed hepatocellularcholangiocarcinoma and hepatocellular carcinoma undergoing a liver transplant

Rereading the article“Propensity-matched analysis of patients with intrahepatic cholangiocarcinoma or mixed hepatocellular-cholangiocarcinoma and hepatocellular carcinoma undergoing a liver transplant”(DOI:10.5306/wjco.v13.i8.688),published on August 24,we observe,with concern,that figures 3 and 4 are wrong.The authors have attached the correct figures for correction.

Evaluating Methods for Dealing with Missing Outcomes in Discrete-Time Event History Analysis: A Simulation Study

Background: In discrete-time event history analysis, subjects are measured once each time period until they experience the event, prematurely drop out, or when the study concludes. This implies measuring event status of a subject in each time period determines whether (s)he should be measured in subsequent time periods. For that reason, intermittent missing event status causes a problem because, unlike other repeated measurement designs, it does not make sense to simply ignore the corresponding missing event status from the analysis (as long as the dropout is ignorable). Method: We used Monte Carlo simulation to evaluate and compare various alternatives, including event occurrence recall, event (non-)occurrence, case deletion, period deletion, and single and multiple imputation methods, to deal with missing event status. Moreover, we showed the methods’ performance in the analysis of an empirical example on relapse to drug use. Result: The strategies assuming event (non-)occurrence and the recall strategy had the worst performance because of a substantial parameter bias and a sharp decrease in coverage rate. Deletion methods suffered from either loss of power or undercoverage issues resulting from a biased standard error. Single imputation recovered the bias issue but showed an undercoverage estimate. Multiple imputations performed reasonably with a negligible standard error bias leading to a gradual decrease in power. Conclusion: On the basis of the simulation results and real example, we provide practical guidance to researches in terms of the best ways to deal with missing event history data.