The identification of circulating tumour cells (CTCs) in peripheral blood is a useful approach to estimate prognosis, monitor disease progression, and measure treatment effects in various malignancies. However, clinical relevance of CTCs is controversial. We attempted to detect viable CTCs in the peripheral blood of gastric cancer patients using a telomerase-specific viral agent.

Background. Standard treatment of early gastric cancer (EGC) after endoscopic resection with risk factors of nodal metastases and incomplete resection is controversial. We investigated optimal management for the patients with potentially noncurative EGC after endoscopic resection.Methods. We retrospectively examined clinicopathological data and surgical outcomes of all patients with clinically solitary gastric adenocarcinoma who underwent curative surgery after a single peroral endoscopic resection at the Digestive Disease Center of Showa University Northern Yokohama Hospital between April 2001 and December 2012. Fisher's exact test was used for univariate analysis. For multivariate analysis, stepwise multiple linear regression was used to identify independent predictors related to lymph node metastasis and remnant of primary tumor.Results. A total of 41 patients were studied. Four patients (9.8%) had lymph node metastases. Primary tumors remained in 6 patients (14.6%). Only venous invasion was statistically significant to lymph node metastasis (P=0.017). With respect to remnant of the primary tumor, pT1b2 tumor invasion (P=0.015) and horizontal margin (P=0.013) were statistically significant.Conclusions. Surgery with limited lymphadenectomy is recommended for tumors with venous invasion or pT1b2 tumor invasion, and additional endoscopic resection may be allowed for tumors with horizontal involvement.

The propagation characteristics of a high-power microwave [electromagnetic (em) wave] in a plasma waveguide are reported. The plasma waveguide is formed by expanding plasmas via the ponderomotive force of the high-power microwave and the microwave pulse remains trapped within the plasma waveguide and is guided in it. With the increase of the incident microwave power, the width of the plasma waveguide increases and the half width of the radial electric field distribution decreases. This shows that the em wave modifies the refractive index of the plasma waveguide area. For a plasma waveguide with narrower width, the microwave propagates along the plasma waveguide at the fundamental TE mode, while as the waveguide width increases the higher mode component starts appearing. Analytical treatment to the propagation of the electromagnetic wave in a dielectric waveguide having a step-index profile and the numerical calculations for the radial distribution of the electric field show fairly good agreement with the results observed in the present experiments.

Background. Although it is possible to visualize gastrointestinal stromal tumors (GIST) of the stomach by endoscopy, their pretreatment histological diagnosis is often difficult. The aim of this study was to investigate predictors of accurate preoperative pathological diagnosis of gastric GIST.Material and Methods. We retrospectively studied patients with gastric GIST who had undergone pretreatment endoscopic biopsy and surgery, and examined their clinicopathological data.Results. Twenty-three patients were eligible. Thirty-four endoscopic biopsies (mean 2.6, range 1–8) were obtained. Preoperative pathological diagnoses of GIST were made in 18 patients. Precise diagnoses were made in 18 (52.9%) of the 34 biopsies. Endoscopic ultrasound (EUS) resulted in precise diagnoses in 11 (91.7%) of the 12 biopsy specimens. Fine-needle aspiration (FNA) biopsy resulted in precise diagnoses in 11 (84.6%) of the 13 biopsy specimens. The accuracy of pathological diagnosis by EUS-guided FNA biopsy was 100%. The procedure of EUS-guided FNA biopsy had no complications or recurrent disease. In a multivariate analysis, only EUS achieved a significantly superior rate of diagnosis (odds ratio, 11.884; 95% confidence interval, 1.204–289.230;P=0.034).Conclusion. EUS-guided FNA biopsy is the most accurate for pretreatment pathological diagnosis of gastric GIST and for prevention of both of early complications and disease recurrence.