[Study on the clinicopathologic characteristics and prognostic difference of gastric stump cancer between non-anastomotic site and anastomotic site].

OBJECTIVE: To evaluate the clinicopathologic characteristics and prognostic difference of gastric stump cancer between non-anastomotic site and anastomotic site.

METHODS: Clinicopathologic data of 149 patients with gastric stump cancer undergoing operation (radical resection and palliative resection) in our department from January 1999 to June 2015 were analyzed retrospectively. Gastric stump cancer was defined as a primary carcinoma detected in the remnant stomach more than 5 years after subtotal gastrectomy for a benign disease(87 cases) or over 10 years after radical subtotal gastrectomy for a malignant disease (62 cases). Patients were divided into the anastomotic site group (72 cases) and the non-anastomotic site group (77 cases) according to tumor sites within the remnant stomach. Clinicopathologic characteristics, operative data, lymph node metastasis and prognosis were compared between the two groups.

RESULTS: Compared with non-anastomotic site group, the T stage, N stage and TNM stage were later in the anastomotic site group. Number of case of T1, T2, T3, and T4 stage in anastomotic site group was 1(1.4%), 2 (2.8%), 17(23.6%) and 52(72.2%), while such number in non-anastomotic site group was 8(10.4%), 10(13.0%), 27(35.1%) and 32(41.6%) respectively(χ(2)=17.665, P=0.001). Number of case of N0, N1, N2, and N3 in anastomotic site group was 28 (38.9%), 10 (13.9%), 23 (31.9%) and 11 (15.3%), while such number in non-anastomotic site group was 55 (71.4%), 10 (13.0%), 7 (9.1%) and 5 (6.5%) respectively(χ(2)=19.421, P=0.000). Number of case of stage I(, II(, III( and IIII( in anastomotic site group was 3(4.2%), 10(13.9%), 47(65.3%) and 12(16.7%), while such number in non-anastomotic site group was 16(20.8%), 40 (51.9%), 15(19.5%) and 6(7.8%) respectively(χ(2)=45.294, P=0.000). The histology and Borrmann classification were worse in anastomotic site group. Anastomotic site group had 19 cases(26.4%) of good differentiation and 53 cases(73.6%) of bad differentiation, while non-anastomotic site group had 43 cases (55.8%) of well-differentiated and 34 cases (44.2%) of poorly-differentiated tumors respectively(χ(2)=13.287, P=0.000). Anastomotic site group had 3 cases (4.2%) of Borrmann I(, 17 cases (23.6%) of Borrmann II(, 47 cases(65.3%) of Borrmann III( and 5 cases (6.9%) of Borrmann IIII(, while non-anastomotic site group had 18 cases (23.4%) of Borrmann I(, 16 cases (20.8%) of Borrmann II(, 34 cases (50.6%) of Borrmann III( and 4 cases (5.2%) of Borrmann IIII( respectively(χ(2)=11.445, P=0.010). Compared with non-anastomotic site group, anastomotic site group had a lower curative resection rate [63.9% (46/72) vs. 89.6% (69/77), χ(2)=13.977, P=0.000], a higher combined organ resection rate [33.3% (24/72) vs. 16.9% (13/77), χ(2)=5.394, P=0.020] and a more metastatic lymph nodes (4.3±4.9 vs. 1.9±3.6, t=3.478, P=0.000). The lymph node metastasis rates of No.4, No.10 and jejunal mesentery root lymph node in anastomotic site group and non-anastomotic site group were 15.3% (11/72) and 5.2% (4/77)(χ(2)=4.178, P=0.041), 9.7% (7/72) and 1.3% (1/77) (χ(2)=5.196, P=0.023), and 25.0% (18/72) and 3.9% (3/77)(χ(2)=13.687, P=0.000), respectively. Median followed up of all the patients was 37(2 to 154) months and the overall 5-year survival rate was 44.1%. The 5-year survival rate was 33.1% in anastomotic site group and 55.2% in non-anastomotic site group, and the difference was statistically significant between two groups (P=0.015). In the subgroup analysis according to the histology differentiation, the 5-year survival rate of patients with well-differentiation was not significantly different between two groups (43.7% vs. 56.2%, P=0.872), but the 5-year survival rate of patients with bad differentiation in anastomotic site group was significantly lower than that in non-anastomotic site group(29.8% vs. 53.8%, P=0.029).

CONCLUSION: Gastric stump cancer locating in anastomotic site indicates worse differentiation histology, higher lymph node metastasis rate, lower curative resection rate and poorer prognosis.