OBJECTIVETo investigate the interval time to canceration, clinicopathological characteristics and prognostic factors of carcinoma in remnant stomach (CRS) in patients with primary benign diseases or primary malignant tumors.

METHODSBased on the criteria of the definition of CRS proposed by Japanese Gastric Cancer Association in 2017, a retrospective analysis was conducted on clinicopathological characteristics of patients diagnosed with CRS at Peking University Cancer Hospital from March 1992 to March 2017. Between patients with primary benign diseases (CBS-B group) and primary malignant tumors (CBS-M group), continuous variables were compared using the Student's t-test or the Mann-Whitney U test; categorical variables were compared using the chi-square test or Fisher's exact test. Spearmen-Rho was used to examine correlation. Survival was estimated and compared using Kaplan-Meier methods. Cox proportional hazards regression was applied to identify independent prognostic factors. Area under ROC curve(AUC) was used to evaluate and compare prediction accuracy.

RESULTSA total of 89 patients were included in the study with a male: female ratio of 5.4 to 1.0. The male: female ratio in CRS-B (n=46) and CRS-M (n=43) group was 14.3 to 1.0 and 2.9 to 1.0 respectively with significant difference (χ=6.091, P=0.019). The interval time to canceration in CRS-B and CRS-M group was 342(36-576) months and 47(12-360) months respectively with significant difference (t=8.887, P=0.000). The interval time to canceration was correlated with the first operative procedure in CRS-B group (r=0.398, P=0.006), while interval time to canceration was correlated with the age at the first operation in CRS-M group (r=0.337, P=0.027). After differentiating the pathological findings of the first operative sample and the second operative sample, 27 patients presented recurrence and 15 patients had new cancer, and the corresponding interval time to canceration was 46(12-132) months and 60(12-360) months respectively with significant difference (t=5.652, P=0.023). In CRS-B group, location of stump carcinoma in gastric intestinal anastomosis, gastric anastomosis, and non-anastomosis area was found in 60.9%(28/46), 23.9%(11/46) and 15.2%(7/46) respectively, and the corresponding percentage in CRS-M group was 39.5%(17/43), 16.3%(7/43) and 44.2%(19/43) respectively without significant difference (χ=4.726, P=0.096). Among 77 patients with radical gastrectomy, the overall surgical complication rate was 20.8%(16/77), including 8 cases of infection and 7 cases of respiratory system diseases. The 3-year survival rate was 78.4% and 62.6% in CRS-B and CRS-M group respectively with significant difference (χ=3.969, P=0.046), indicating better prognosis of CRS-B patients. The AUC for the lymph nodes ratio and N staging was 0.725 and 0.639 respectively. Multivariate analysis showed the pathological T staging was an independent risk factor of prognosis (HR=1.192, 95%CI:1.032-1.376, P=0.017).

CONCLUSIONSMen have more CRS than women. The interval time to canceration is correlated to the first operative procedure for CRS-B patients, while it is correlated to the age at the first operation for CRS-M patients. The major location of CRS is in the gastrointestinal anastomosis for CRS-B patients and in non-anastomosis area for CRS-M patients. Main postoperative complications include respiratory and infectious complications. Pathological T staging is an independent prognostic risk factor for CRS patients.