title: Low prevalence of microsatellite instability in interval gastric cancers.
abstract: OBJECTIVE
  Esophagogastroduodenoscopy (EGD) is recommended at 2-year intervals in countries with a high prevalence of gastric cancer. The aim of this study was to determine whether interval gastric cancers that develop within 2 years of a previous complete screening are associated with microsatellite instability (MSI).
  
  
  METHODS
  Newly diagnosed gastric cancer patients who had undergone gastrectomy were included. Of these 459 patients, 177 were classified as interval gastric cancer since they were diagnosed within 2 years of a previous EGD. Noninterval gastric cancer patients were subclassified into 65 patients who underwent previous EGD between the past 2 and 10 years and 217 patients without EGD during the last 10 years. Analysis for MSI was conducted using two mononucleotide and three dinucleotide markers.
  
  
  RESULTS
  MSI was found more frequently in noninterval gastric cancers than in interval gastric cancers (p = 0.009). Interval gastric cancers were associated with a higher prevalence of early gastric cancer (p = 0.006), smaller size (p < 0.001), and lower TNM stages (p = 0.006). On logistic regression analysis, noninterval gastric cancers were related to MSI (p = 0.010) and larger size (≥4 cm) (p = 0.009). Subjects with interval gastric cancer showed better survival than those with noninterval gastric cancer (p = 0.006).
  
  
  CONCLUSIONS
  During a 2-year screening interval, noninterval gastric cancers tend to be larger, more advanced, and associated with MSI. Biannual EGD screening is effective for detecting small gastric cancers at an early stage, but is not useful in detecting gastric cancers with MSI.
authors.affiliation: Department of Internal Medicine, Konkuk University School of Medicine, 120-1 Neungdong-ro, Gwangjin-gu, Seoul, 143-729, Korea.
authors.forename: Hong Seok
authors.initials: HS
authors.lastname: Choi
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Jeong Hwan
authors.initials: JH
authors.lastname: Kim
authors.forename: In-Kyung
authors.initials: IK
authors.lastname: Sung
authors.forename: Hyung Seok
authors.initials: HS
authors.lastname: Park
authors.forename: Chan Sup
authors.initials: CS
authors.lastname: Shim
authors.forename: Choon Jo
authors.initials: CJ
authors.lastname: Jin
authors.forename: Hye Seung
authors.initials: HS
authors.lastname: Han
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D055088:Early Detection of Cancer; D016145:Endoscopy, Digestive System; D005260:Female; D005743:Gastrectomy; D020022:Genetic Predisposition to Disease; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D009367:Neoplasm Staging; D016017:Odds Ratio; D010641:Phenotype; D011237:Predictive Value of Tests; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D013997:Time Factors; D047368:Tumor Burden