title: Undifferentiated-type gastric adenocarcinoma: prognostic impact of three histological types.
abstract: BACKGROUND
  The prognostic value of the three constituents of undifferentiated-type gastric adenocarcinoma remains unclear. The present study assessed the clinicopathological characteristics and prognosis of undifferentiated-type mucinous adenocarcinoma (uMAC) and signet ring cell carcinoma (SRC) compared with those of poorly differentiated adenocarcinoma (PDAC).
  
  
  METHODS
  In total, 1,376 patients with undifferentiated-type gastric adenocarcinoma were included, consisting of 1,002 patients diagnosed with PDAC, 54 with uMAC and 320 with SRC. Clinicopathological factors and survival rates were compared among the three histological types.
  
  
  RESULTS
  Significant differences in the distribution of pathological stages were observed among the groups. Patients with SRC had a significantly better survival rate than those with PDAC or uMAC, in both the all patients including non-curative resected patients and curative-resected groups. In addition, there was significant difference in survival between the PDAC and uMAC groups. Multivariate analysis suggested that age, gender, tumor depth, lymph node metastasis and curability significantly affected survival. Histological type was not an independent prognostic factor. There was no significant difference in the pattern of recurrence among the three groups.
  
  
  CONCLUSIONS
  The uMAC and SRC had worse and favorable prognosis compared with PDCA, respectively. However, there were no differences in survival by pathological stage, thus histological type was not an independent predictor of prognosis.
authors.affiliation: Division of Gastrointestinal Surgery, Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, South Korea. painkiller9@catholic.ac.kr
authors.forename: Han Hong
authors.initials: HH
authors.lastname: Lee
authors.forename: Kyo Young
authors.initials: KY
authors.lastname: Song
authors.forename: Cho Hyun
authors.initials: CH
authors.lastname: Park
authors.forename: Hae Myung
authors.initials: HM
authors.lastname: Jeon
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D018279:Carcinoma, Signet Ring Cell / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D005743:Gastrectomy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D013274:Stomach Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D015996:Survival Rate