Prognostic value of preoperative weight loss-adjusted body mass index on survival after esophagectomy for esophageal squamous cell carcinoma

BACKGROUND The impact of body mass index(BMI)on survival in patients with esophageal squamous cell carcinoma(ESCC)undergoing surgery remains unclear.Therefore,a definition of clinically significant BMI in patients with ESCC is needed.AIM To explore the impact of preoperative weight loss(PWL)-adjusted BMI on overall survival(OS)in patients undergoing surgery for ESCC.METHODS This retrospective study consisted of 1545 patients who underwent curative resection for ESCC at West China Hospital of Sichuan University between August 2005 and December 2011.The relationship between PWL-adjusted BMI and OS was examined,and a multivariate analysis was performed and adjusted for age,sex,TNM stage and adjuvant therapy.RESULTS Trends of poor survival were observed for patients with increasing PWL and decreasing BMI.Patients with BMI≥20.0 kg/m2 and PWL<8.8%were classified into Group 1 with the longest median OS(45.3 mo).Patients with BMI<20.0 kg/m2 and PWL<8.8%were classified into Group 2 with a median OS of 29.5 mo.Patients with BMI≥20.0 kg/m2 and PWL≥8.8%(HR=1.9,95%CI:1.5-2.5),were combined into Group 3 with a median OS of 20.1 mo.Patients in the three groups were associated with significantly different OS(P<0.05).In multivariate analysis,PWL-adjusted BMI,TNM stage and adjuvant therapy were identified as independent prognostic factors.CONCLUSION PWL-adjusted BMI has an independent prognostic impact on OS in patients with ESCC undergoing surgery.BMI might be an indicator for patients with PWL<8.8%rather than≥8.8%.

Multi-symplectic method for the generalized(2+1)-dimensionalKdV-mKdV equation

In the present paper,a general solution involving three arbitrary functions for the generalized(2+1)dimensional KdV-mKdV equation,which is derived fromthe generalized(1+1)-dimensional KdV-mKdV equation,is first introduced by means of the Wiess,Tabor,Carnevale(WTC) truncation method.And then multisymplectic formulations with several conservation lawstaken into account are presented for the generalized(2+1)dimensional KdV-mKdV equation based on the multisymplectic theory of Bridges.Subsequently,in order tosimulate the periodic wave solutions in terms of rationalfunctions of the Jacobi elliptic functions derived from thegeneral solution,a semi-implicit multi-symplectic schemeis constructed that is equivalent to the Preissmann scheme.From the results of the numerical experiments,we can conclude that the multi-symplectic schemes can accurately simulate the periodic wave solutions of the generalized(2+1)dimensional KdV-mKdV equation while preserve approximately the conservation laws.

Timing of surgery after neoadjuvant chemoradiotherapy affects oncologic outcomes in patients with esophageal cancer

BACKGROUND The optimal time interval between neoadjuvant chemoradiotherapy(nCRT)and esophagectomy in esophageal cancer has not been defined.AIM To evaluate whether a prolonged time interval between the end of nCRT and surgery has an effect on survival outcome in esophageal cancer patients.METHODS We searched PubMed,Embase,Web of Science,the Cochrane Library,Wanfang and China National Knowledge Infrastructure databases for relevant articles published before November 16,2019,to identify potential studies that evaluated the prognostic role of different time intervals between nCRT and surgery in esophageal cancer.The hazard ratios and 95%confidence intervals(95%CI)were merged to estimate the correlation between the time intervals and survival outcomes in esophageal cancer,esophageal squamous cell carcinoma and adenocarcinoma using fixed-and random-effect models.RESULTS This meta-analysis included 12621 patients from 16 studies.The results demonstrated that esophageal cancer patients with a prolonged time interval between the end of nCRT and surgery had significantly worse overall survival(OS)[hazard ratio(HR):1.107,95%CI:1.014-1.208,P=0.023]than those with a shorter time interval.Subgroup analysis showed that poor OS with a prolonged interval was observed based on both the sample size and HRs.There was also significant association between a prolonged time interval and decreased OS in Asian,but not Caucasian patients.In addition,a longer wait time indicated worse OS(HR:1.385,95%CI:1.186-1.616,P<0.001)in patients with adenocarcinoma.CONCLUSION A prolonged time interval from the completion of nCRT to surgery is associated with a significant decrease in OS.Thus,esophagectomy should be performed within 7-8 wk after nCRT.