title: At which stage of gastric cancer progression do levels of carcinoembryonic antigen and carbohydrate antigen 19-9 increase? Application in advanced gastric cancer treatment.
abstract: OBJECTIVE
  Since there are no proven tumor markers that reflect the course of gastric cancer, carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) are commonly used alternatives. However, the degree of progression that corresponds to an increase in these markers, and the values of these markers at different cancer stages, remains unclear.
  
  
  METHODS
  This study enrolled 1,733 gastric cancer patients who underwent surgery and whose pre-operative CEA and CA19-9 levels were known. Survival curves and mean values of the two markers were compared according to the degree of cancer progression: serosa-unexposed (SU), serosa-exposed (SE), direct invasion (DI), localized seeding (P1), and extensive seeding (P2).
  
  
  RESULTS
  The 5-year overall survival rates at each stage differed significantly, except between DI and P1 patients (17.1% vs. 10.5%, P=0.344). The mean CEA values in SU, SE, DI, P1, and P2 patients were 5.80, 5.48, 13.36, 8.06, and 22.82, respectively. The CA19-9 values for these patients were 49.40, 38.97, 101.67, 73.77, and 98.57, respectively. The increase in CEA in P2 patients was statistically significant (P=0.002), and the increases in CA19-9 in DI and P2 patients were significant (P=0.025, 0.007, respectively). There was a fair correlation between the two markers in P2 patients (r=0.494, P<0.001).
  
  
  CONCLUSIONS
  CA19-9 can be used to assess DI of gastric cancer into adjacent organs. Both markers are useful for predicting the presence of extensive peritoneal seeding.
authors: Division of Gastrointestinal Surgery, Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Eui Soo
authors: ES
authors: Han
authors: Division of Gastrointestinal Surgery, Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Han Hong
authors: HH
authors: Lee
authors: Division of Gastrointestinal Surgery, Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Jun Suh
authors: JS
authors: Lee
authors: Division of Gastrointestinal Surgery, Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Kyo Young
authors: KY
authors: Song
authors: Division of Gastrointestinal Surgery, Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Cho Hyun
authors: CH
authors: Park
authors: Division of Gastrointestinal Surgery, Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors: Hae Myung
authors: HM
authors: Jeon
keywords: Carcinomatosis; Disease progression; Neoplasm invasiveness; Stomach neoplasms; Tumor markers, biological