title: The decision criterion of histological mixed type in "T1/T2" gastric carcinoma--comparison between TNM classification and Japanese Classification of Gastric Cancer.
abstract: BACKGROUND
  This study was designed to evaluate the clinical significance of undifferentiated component in differentiated T1/T2 gastric adenocarcinoma.
  
  
  METHODS
  Two hundred thirty-one patients who underwent curative gastrectomy were diagnosed pathologically as differentiated type T1/T2 gastric cancer according to Japanese Classification of Gastric Carcinoma (JCGC). The patients were divided into subgroups, pure differentiated type (pure D group, 181 patients) and differentiated-predominant mixed type (D > U group, 51 patients). The clinicopathological features of D > U group were compared with those of pure D group, and also those of undifferentiated-predominant type (U > D group).
  
  
  RESULTS
  Patients in D > U group were more likely to have larger and deeper tumors with lymphatic invasion and metastases than pure D group. However, there was no significant difference in clinicopathological factors between D > U and U > D groups, except for depth of tumor invasion. The postoperative 5-year survival rate of D > U group was significantly poorer than that of pure D group (88% and 98%, P = 0.011). Multivariate analysis revealed the presence of undifferentiated component was an independent prognostic factor.
  
  
  CONCLUSIONS
  The presence of undifferentiated component in differentiated T1/T2 gastric cancer is associated with tumor progression. Therefore, the decision criterion of histological mixed type in TNM classification is better suited than JCGC in T1/T2 gastric cancer.
authors.affiliation: Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kawaramachihirokoji, Kamigyo-ku, Kyoto, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shimizu
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ichikawa
authors.forename: Shuhei
authors.initials: S
authors.lastname: Komatsu
authors.forename: Kazuma
authors.initials: K
authors.lastname: Okamoto
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shiozaki
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Fujiwara
authors.forename: Yasutoshi
authors.initials: Y
authors.lastname: Murayama
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kuriu
authors.forename: Hisashi
authors.initials: H
authors.lastname: Ikoma
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Nakanishi
authors.forename: Toshiya
authors.initials: T
authors.lastname: Ochiai
authors.forename: Yukihito
authors.initials: Y
authors.lastname: Kokuba
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Kishimoto
authors.forename: Akio
authors.initials: A
authors.lastname: Yanagisawa
authors.forename: Eigo
authors.initials: E
authors.lastname: Otsuji
mesh_terms: D000230:Adenocarcinoma / Q000145:classification* / Q000401:mortality / Q000556:secondary*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003657:Decision Making; D005260:Female; D005743:Gastrectomy; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D013274:Stomach Neoplasms / Q000145:classification* / Q000401:mortality / Q000473:pathology*; D015996:Survival Rate