Myeong-Cherl Kook

Effect of repeated endoscopic screening on the incidence and treatment of gastric cancer in health screenees.

Objectives Early gastric cancer (EGC) can be treated by minimally invasive endoscopic resection and has an excellent prognosis. The aim of this study was to investigate whether repeated esophagogastroduodenoscopy (EGD) screening is an effective method for detecting EGC that can be treated by endoscopic resection. Methods For patients diagnosed with gastric cancer in the Korean National Cancer Center screening program, we analyzed the incidence of gastric cancer, clinicopathological characteristics, and treatment modality according to whether they had (repeated screening group) or not (infrequent screening group) undergone EGD screening within 2 years before diagnosis. Results Of the 18 414 patients who underwent EGD, 81 (0.44%) were found to have gastric cancer. Incidence of gastric cancer in repeated screening group was lower than that of infrequent screening group (multiple adjusted odds ratio=0.45, 95% confidence interval: 0.26–0.77, P=0.004). The proportion of EGCs was 96% (25 of 26) n the repeated screening group and 71% (34 of 48) in the infrequent screening group (P=0.01). Mean (SD) tumor size was smaller [1.9 (1.2) vs. 3.0 (1.6) cm, P=0.01] and the proportion of intramucosal cancer was higher [81% (21 of 26) vs. 50% (24 of 48), P=0.02] in the former than in the latter. Endoscopic resection was performed more frequently in the repeated screening group [54% (14 of 26) vs. 23% (11 of 48), P=0.007]. Conclusion Repeated endoscopic screening within 2 years decreased the incidence of gastric cancer and endoscopic resection could be applied to more patients who underwent EGD screening within 2 years.

Surgical Indication for Non-curative Endoscopic Resection in Early Gastric Cancer

BackgroundEndoscopic resection (ER) is an effective treatment for early gastric cancer (EGC) without lymph node metastasis. However, after ER additional surgery may be needed to manage the risks presented by residual cancer or lymph node metastasis.MethodsER was performed on 344 gastric adenocarcinomas between November 2001 and April 2006 at the Korean National Cancer Center under the strict pre-procedural indication. The authors performed operations in 43 patients due to: residual mucosal cancer, a mucosal cancer larger than 3 cm, or a submucosal cancer regardless of size or margin involvement. ER and surgical specimens were reviewed and analyzed for residual cancer and lymph node metastasis.ResultsBased on examinations of ER specimens, cancer was confined to the mucosal layer in 15 patients (34.9%) and invaded the submucosal layer in 28 patients (65.1%). Surgical specimens showed residual cancer in 17 patients (39.5%) and lymph node metastasis in four (9.3%). Neither residual cancer nor lymph node metastasis was found in patients with less than 500 μm submucosal invasion without margin involvement in ER specimens. In three of four patients with lymph node metastasis, the depth of submucosal invasion was 500 μm or more; the remaining patient had a 4-cm-sized differentiated mucosal cancer.ConclusionsWhen a pathologic evaluation of an ER specimen reveals more than 500 μm of submucosal invasion or a mucosal cancer of larger than 3 cm, surgery should be considered due to the risk of lymph node metastasis.

Endoscopic Ultrasound and Computed Tomography in Restaging and Predicting Prognosis After Neoadjuvant Chemotherapy in Patients With Locally Advanced Gastric Cancer

The objective of the current study was to assess the staging accuracy and prognostic role of preoperative endoscopic ultrasound (EUS) and computed tomography (CT) in patients with locally advanced gastric cancer (LAGC) after neoadjuvant chemotherapy.

Is the New Seventh AJCC/UICC Staging System Appropriate for Patients with Gastric Cancer?

BACKGROUND The purpose of this study was to compare the clinical usefulness of the seventh Union Internationale Contre le Cancer/American Joint Committee on Cancer (AJCC/UICC) staging system vs the sixth AJCC/UICC staging system in patients with gastric cancer. STUDY DESIGN Included were 1,799 patients who underwent surgery for gastric cancer between January 2001 and June 2005 at the National Cancer Center (South Korea). For the sixth and seventh AJCC/UICC staging systems, survival outcomes stratified by stage, by T classification, and by N classification were summarized using Kaplan-Meier curves and compared statistically using a log rank test; survival differences were quantified using hazard ratios estimated from a Cox regression model. The 2 systems were compared in terms of prognostic performances using the linear trend chi-square test, likelihood ratio chi-square test, and Akaike information criterion (AIC) in the Cox regression analysis. RESULTS Significant survival differences between each stage were not found using the seventh staging system, especially for stages IB, IIA, and IIB (p = 0.14 and p = 0.11). The sixth staging system had higher linear trend chi-square score and likelihood ratio chi-square score, which means better discriminatory ability, monotonicity, and homogeneity, and had smaller AIC, which indicates better optimistic prognostic stratification, especially in the N classification. The modified staging system combining the T classification of the seventh AJCC/UICC system and the N classification of the sixth system showed better prognostic performance compared with each separate version (sixth or seventh) of the staging system. CONCLUSIONS The seventh AJCC/UICC staging system is not more clinically useful than the sixth system in surgically treated patients with gastric cancer because of an inappropriate N classification. A new TNM system is required with a different N classification.

Sentinel Node Biopsy Using Dye and Isotope Double Tracers in Early Gastric Cancer

BackgroundThe results of sentinel node (SN) biopsy have been improved by the use of dye and isotope double tracers in melanoma and breast cancer. However, the usefulness of this double tracer technique has not been determined in gastric cancer. The aim of this study was to investigate the possibility of improving SN biopsy results by using double tracers in gastric cancer.MethodsSixty-four gastric adenocarcinoma patients preoperatively diagnosed as cT1N0, were enrolled in the study. 99mTc tin colloid was injected by preoperative endoscopy, and lymphoscintigraphy was performed prior to operation. After laparotomy, isosulfan blue was intraoperatively injected using an endoscope. Blue-stained or radioactive nodes were identified and defined as SNs. Gastrectomy with D2 lymphadenectomy was performed in all patients. All dissected lymph nodes were evaluated for metastasis by hematoxylin and eosin staining and immunohistochemistry.ResultsSN detection rates using dye, isotope, or both tracers were 95.3%, 84.4%, and 96.9%, respectively, and their corresponding sensitivities were 52.9%, 52.9%, and 70.6%. In the pT1 subset, the sensitivity of the double tracer was 87.5%; and in a subset of tumors with diameter <4.5 cm, this was also 87.5%.ConclusionsThese findings confirm that SN biopsy results are improved by using double tracers in gastric cancer and suggest that SN biopsy is suitable in cases of small-sized early gastric cancer.

Feasibility of laparoscopic sentinel basin dissection for limited resection in early gastric cancer

The clinical applications of sentinel node (SN) biopsies in early gastric cancer are limited because of low sensitivity. Sentinel basin (SB) dissection has been suggested as alternative to SN biopsy to improve sensitivity. The aim of this study was to examine the feasibility of laparoscopic SB dissection.

Biopsy site for detecting Helicobacter pylori infection in patients with gastric cancer

Background:  Helicobacter pylori eradication is recommended in post‐gastric cancer resection, but premalignant changes may prevent the detection of H. pylori. The aim of this study was to determine appropriate biopsy site for detecting H. pylori in gastric cancer patients.

Effects of interleukin-10 polymorphisms, Helicobacter pylori infection, and smoking on the risk of noncardia gastric cancer.

Objective Both variations in the interleukin-10 (IL10) gene and environmental factors are thought to influence inflammation and gastric carcinogenesis. Therefore, we investigated the associations between IL10 polymorphisms, Helicobacter pylori (H. pylori) infection, and smoking in noncardia gastric carcinogenesis in Koreans. Methods We genotyped three promoter polymorphisms (-1082A>G, -819T>C, and -592 A>C) of IL10 in a case-control study of 495 noncardia gastric cancer patients and 495 sex- and age-matched healthy controls. Multiple logistic regression models were used to detect the effects of IL10 polymorphisms, H. pylori infection, and smoking on the risk of gastric cancer, which was stratified by the histological type of gastric cancer. Results The IL10-819C and -592C alleles were found to have complete linkage disequilibrium, and all three IL10 polymorphisms were associated with an increased risk of intestinal-type noncardia gastric cancer. These associations were observed only in H. pylori-positive subjects and current smokers. A statistically significant interaction between the IL10-592 genotype and H. pylori infection on the risk of intestinal-type gastric cancer was observed (P for interaction  = 0.047). In addition, H. pylori-positive smokers who were carriers of either the IL10-1082G (OR [95% CI]  = 17.76 [6.17−51.06]) or the -592C (OR [95% CI]  = 8.37 [2.79−25.16]) allele had an increased risk of intestinal-type gastric cancer compared to H. pylori-negative nonsmokers homozygous for IL10-1082A and -592A, respectively. The interaction between the IL10-1082 polymorphism and the combined effects of H. pylori infection and smoking tended towards significance (P for interaction  = 0.080). Conclusions Inflammation-related genetic variants may interact with H. pylori infection and smoking to increase the risk of noncardia gastric cancer, particularly the intestinal-type. These findings may be helpful in identifying individuals at an increased risk for developing noncardia gastric cancer.

The Association Between Helicobacter pylori Status and Incidence of Metachronous Gastric Cancer After Endoscopic Resection of Early Gastric Cancer

The long‐term effect of Helicobacter pylori eradication in preventing metachronous gastric cancer (GC) development after endoscopic resection (ER) of early gastric cancer (EGC) remains controversial. The aim of this study was to investigate the effect of H. pylori status on the incidence of metachronous GC after ER during long‐term follow‐up.

Association of CYP2A6 polymorphisms with S-1 plus docetaxel therapy outcomes in metastatic gastric cancer

AIMS S-1, an oral fluoropyrimidine, contains tegafur, which is converted to 5-fluorouracil mainly by CYP2A6. We evaluated the association between CYP2A6 polymorphisms and treatment outcome in metastatic gastric cancer patients treated with S-1 plus docetaxel. MATERIALS & METHODS Chemonaive patients received S-1 40 mg/m(2) twice daily on days 1-14 and docetaxel 35 mg/m(2) on days 1 and 8 of a 3-week cycle. We analyzed the wild-type (W) allele (CYP2A6*1) and four variant (V) alleles that abolish or reduce enzyme activity (CYP2A6*4, *7, *9 and *10). A total of 50 patients were enrolled. RESULTS The genotype frequencies were as follows: W/W (n=14, 28%), W/V (n=26, 52%) and V/V (n=0, 20%). Patients having fewer variant alleles had significantly better response rates (W/W vs W/V vs V/V=79 vs 65 vs 30%; p=0.04) and median progression-free survival (W/W vs W/V vs V/V=8.1 vs 6.9 vs 3.1 months; p=0.0009). CONCLUSION Our findings showed that the CYP2A6 genotype correlated with the treatment efficacy of S-1-based chemotherapy in previously untreated metastatic gastric cancer patients.