Clinicopathological Features of Upper Third Gastric Cancer during a 21-Year Period (Single Center Analysis)

Abstract

Purpose: The aim of this study was to determine proportions of upper third gastric cancer (UTG) among all gastric cancers and analyze clinicopathological features of the disease.

Materials and methods: The medical records of 12,300 patients who underwent gastric surgery between 1986 and 2006 at Seoul National University Hospital (SNUH) were retrospectively reviewed. Clinicopathological features of 1,260 patients with UTG and 9,929 patients with middle or lower third gastric cancer (MLG) were compared, and annual proportions of UTG were evaluated.

Results: The proportion of patients with UTG rapidly increased from 2.6% in 1986 to 12.5% in 1992. However, linear regression analysis showed that the rate of increase was reduced (0.21%/year) after 1992 (12.5% to 14.2% from 1992 to 2006). Compared with the MLG group, the UTG group had a lower proportion of (22.3% vs. 39.7%, P<0.001) and a greater proportion of stage III/IV disease (39.4% vs. 31.7%, P<0.001). The UTG group also had larger tumors than the MLG group in stages I/II and III (3.5 cm/5.3 cm/6.5 cm vs. 3.2 cm/5.0 cm/5.8 cm, P=0.020/0.028 /<0.001), a higher proportion of undifferentiated cancer (63.1% vs. 53.7%, P<0.001), and less intestinal Lauren's type (38.8% vs. 47.4%, P<0.001). The 5-year survival rate of the UTG group was significantly lower than that of the MLG group in stages I/II and III (85.6%/63.1%/34.2% vs. 91.6%/ 69.2%/44.7%, P<0.001/0.028/0.006).

Conclusions: The proportion of UTGs has increased over the last two decades at SNUH, but the rate of increase has been greatly reduced since 1992. The UTG group showed a poorer prognosis compared with the MLG group in stages I/II and III.

Keywords: Gastric cardia; Gastric fundus; Incidence; Prognoisis; Stomach neoplasms.

Fig. 1

Chronological changes in gastric cancer patient numbers based on tumor location. (A) Annual number of UTG and MLG at SNUH. UTG was 2.6% (9 patients) in 1986 and rapidly increased to 12.5% (66 patients) in 1992. It reached a peak of 16.2% (96 patients) in 2004. A temporary drop in the rate to 12.5% (40 patients) was observed in 2000, which may be related to a medical strike at the time in Korea for separating medical practice and pharmaceutical dispensing system. (B) Estimated increase in the rates of UTG by linear regression analysis. Before 1992, UTG had been increasing at the rate of 1.69% per year (P<0.001, R²=0.913); since 1992, the rate has reduced at 0.21% per year (P=0.028, R²=0.321). UTG = upper third gastric cancer; MLG = middle or lower third gastric cancer; SNUH = Seoul National University Hospital.

Fig. 2

Chronological changes in gastric cancer stages based on the tumor location. The proportion of stage I and II cancer increased in both groups, whereas the proportion of stage III and IV decreased; it is not clear whether this represents a real increase in the prevalence of EGC or is simply the result of greater diagnoses due to increased health screening. (A) Annual TNM stage distribution in UTG. (B) Annual TNM stage distribution in MLG. EGC = early gastric cancer; MLG = middle or lower third gastric cancer.

Fig. 3

Survival curve of gastric cancer in each stage based on the tumor locaton. Five-year survival rates in UTG were significantly lower compared with MLG in stage I, II, and III; there was no significant difference in stage IV. (A) Stage I. (B) Stage II. (C) Stage III. (D) Stage IV. MLG = middle or lower third gastric cancer; UTG = upper third gastric cancer; YS = year survival rate. ^‡P<0.05, statistically significant.