Prognostic factors in stage IB gastric cancer

AIM:To identify the subset of patients with stage IB gastric cancer with an unfavorable prognosis.METHODS:Overall survival(OS)rates were examined in 103 patients with stage IB(T1N1M0 and T2N0M0)gastric cancer between January 2000 and December2011.Univariate and multivariate analyses were performed to identify risk factors using a Cox proportional hazards model.RESULTS:The OS rates of patients with T1N1 and T2N0 cancer were 89.2%and 94.1%at 5-years,re-spectively.Both univariate and multivariate analyses demonstrated that tumor location was the only significant prognostic factor.The OS rate was 81.8%at5-years when the tumor was located in the upper third of the stomach and was 95.5%at 5-years when the tumor was located in the middle or lower third of the stomach(P=0.0093).CONCLUSION:These data may suggest that tumor location is associated with survival in patients with stage IB gastric cancer.

Feasibility of gastric endoscopic submucosal dissection in elderly patients aged≥80 years

BACKGROUND Endoscopic resection,especially endoscopic submucosal dissection(ESD),is increasingly performed in elderly patients with early gastric cancer,and lesions beyond the expanded indications are also resected endoscopically in some patients.It is essential to assess whether gastric ESD is safe and suitable for elderly patients and investigate what type of lesions carry an increased risk of ESD-related complications.AIM To assess the efficacy and feasibility of gastric ESD for elderly patients,and define high-risk lesions and prognostic indicators.METHODS Among a total of 1169 sessions of gastric ESD performed in Kanagawa Cancer Center Hospital from 2006 to 2014,179 sessions(15.3%)were performed in patients aged≥80 years,and 172 of these sessions were done in patients with a final diagnosis of gastric cancer.These patients were studied retrospectively to evaluate short-term outcomes and survival.The short-term outcomes included the rates of en bloc resection and curative resection,complications,and procedurerelated mortality.Curability was assessed according to the Japanese Gastric Cancer Treatment Guidelines 2010.Fisher’s exact test was used to statistically analyze risk factors.Clinical characteristics of each group were compared using Fisher’s exact test and Mann-Whitney U test.Survival rates at each time point were based on Kaplan-Meier estimation.Overall survival rates were compared between patients with gastric cancer in each group with use of the log-rank test.To identify prognostic factors that jointly predict the hazard of death while controlling for model overfitting,we used the least absolute shrinkage and selection operator(LASSO)Cox regression model including factors curative/noncurative,age,gender,body mass index,prognostic nutritional index,Charlson comorbidity index(CCI),Glasgow prognostic score,neutrophil-to-lymphocyte ratio,and antithrombotic agent use.We selected the LASSO Cox regression model that resulted in minimal prediction error in 10-fold cross-validation.P<0.05 was considered statistically significant.RESULTS The en bloc dissection rate was 97.1%,indicating that a high quality of treatment was achieved even in elderly patients.As for complications,the rates of bleeding,perforation and aspiration pneumonitis were 3.4%,1.1%and 0.6%,respectively.These complication rates indicated that ESD was not associated with a particularly higher risk in elderly patients than in nonelderly patients.A dissection incision>40 mm,lesions associated with depressions,and lesions with ulcers were risk factors for post-ESD bleeding,and location of the lesion in the upper third of the stomach was a risk factor for perforation in elderly patients(P<0.05).Location of the lesion in the lower third of the stomach tended to be associated with a higher risk of bleeding.The overall survival(OS)did not differ significantly between curative and noncurative ESD(P=0.69).In patients without additional surgery,OS rate was significantly lower in patients with a high CCI(≥2)than in those with a low CCI(≤1)(P<0.001).CONCLUSION Gastric ESD is feasible even in patients aged≥80 years.Observation without additional surgery after noncurative ESD is reasonable,especially in elderly patients with CCI≥2.

Heat Transfer Characteristics of Work Fluid Including Phase Change Material That Flow into Heating Surface from Narrow Path

Use of the low temperature (less than 100°C) energy contributes to effective use of heat resources. The cost recovery by power generation is difficult by using an existing system (the binary cycle or the thermoelectric conversion element), because the initial investment is large. The final purpose of this research is development of the low temperature difference drive engine supposing use in a hot-springs resort as a power source for electric power generation. In order that a traveler may look at and delight a motion of an engine, it is made to drive at low-speed number of rotations. An engine cycle of this study is aimed at the development of Stirling cycle engine which can maintain high efficiency in small size. This kind of engine has simple structure;it brings low cost, and it is easy to perform maintenance. However, it is difficult to obtain enough output by this type of engine, because of its low temperature difference. This paper deals with the heat transfer characteristic that the working fluid including a phase change material flows into the heating surface from the narrow path. In order to increase the amount of the heat transmission, Diethylether is added to the working fluid. Diethylether is selected as a phase change material (PCM) that has the boiling point which exists between the heat source of high temperature and low temperature. The parameters of the experiment are additive amount of PCM, rotational speed of the displacer piston and temperature of heat transfer surface. It is shown that it is possible to make exchange of heat amount increase by adding phase change material. The result of this research shows the optimal condition of the difference in temperature in heat processing, number of revolutions, and addition concentration of PCM.

Study of Cycle Output Improvement by Work-Fluid Including Phase Change Material

This paper deals with the output improvement of heating and cooling cycle by using the work-fluid including phase change material.The experimental study is carried out by heat exchange between work-fluid and heat transfer surface.The work-fluid is flown to a high temperature or a low temperature heat transfer surface from the narrow path.In order to increase the amount of the heat transmission,a trace of Diethylether(boiling point 34.8 ℃),as a phase change material(PCM),is added to the work-fluid.The parameters of the experiment are additive amount of PCM,the rotational speed of the displacer piston and the temperature of heat transfer surface.It is clarified that the increasing of engine cycle output is brought by the PCM addition.The effect of PCM addition is evaluated by output ratio which is defined from the experimental cycle output data.The requirements for acquiring the increasing effect of output by adding PCM are clarified.