[Meta-analysis of gastric stump cancer after gastrectomy for gastric cancer].

Objective: To study the clinicopathological features and prognosis of gastric stump cancer (GSC) following subtotal gastrectomy for gastric cancer, to compare the clinicopathologic differences between narrow GSC and generalized GSC, and to compare the prognosis between GSC and primary proximal gastric cancer (PPGC) after radical resection.

Methods: Literatures of GSC-associated clinical study were searched by computer from the Cochrane Library, Medline, PubMed, CNKI, Wanfang and VIP databases, and the retrieval period was from the establishment of database to December 31, 2017.

Inclusion Criteria: (1) GSC was defined as a carcinoma arising in the gastric remnant after radical gastrectomy for gastric cancer, and confirmed by the pathological or histological examination, the elapsed time from the initial operation was not considered in the definition. (2) Retrospective or prospective clinical cohort study. (3) Study included at least one of below items: gender, anastomotic type in gastric cancer surgery, the interval between the initial surgery and diagnosis of GSC, the location, treatment, pathological differentiation, pathologic stage, lymph node metastasis rate and prognosis of GSC. (4) When similar studies were reported by the same institution or author, either the better quality study or the newest publication was chosen.

Exclusion Criteria: (1) Abstracts, reviews, case reports, meeting record, editorials and repeated research. (2) Studies including patients with initial non-gastric cancer. In this study, gastric stump cancer(GSC) after gastric cancer was divided into two groups: the incidence without limit interval time (generalized GSC group) and above 10 years (narrow GSC group). Selective trials were Meta-analyzed by the Stata13.0 software and statistical analysis was performed using SPSS 21.0 software.

Results: A total of 27 literatures were finally enrolled, which comprised 1463 GSC patients, including 1146 males and 317 females. The generalized group and narrow GSC group had 921 and 542 patients respectively. The generalized GSC group and the narrow GSC group did not significantly differ in terms of previous reconstruction mode, types of differentiation, pathologic T staging, postoperative pathology tumor-node-metastases staging, and distant metastasis rate (χ=2.341, 0.926, 0.350, 0.965, 2.311 respectively, all P>0.05). As compared to generalized GSC group, narrow GSC group had higher ratio of male patients (82.8% vs. 75.7%, χ=9.909, P=0.002), more lesions locating in anastomotic stoma (37.8% vs. 26.1%, χ=18.091, P=0.000), higher ratio of patients undergoing radical resection (84.2% vs. 70.3%, χ=11.738, P=0.001), higher positive rate of postoperative lymph node (45.8% vs. 34.5%, χ=6.319, P=0.012), and larger size of tumor [(5.9±2.2) cm vs. (4.5±1.9) cm, t=9.151, P=0.000]. The overall 5-year survival rate and postoperative pathology stage III(-IIII( survival ratio in narrow GSC group were higher compared to general GSC group (42.7% vs. 30.6% and 27.5% vs. 18.1%, respectively), which were significantly different (χ=10.938, P=0.000; χ=4.128, P=0.042), while the postoperative pathology stage I(-II( survival ratio was not significantly different between two groups (67.3% vs. 67.0% respectively, χ=0.015, P=0.92). There was no significant difference in the 5-year survival rate between GSC with radical resection and PPGC(RR=1.04, 95%CI:0.79-1.36, P=0.805) and the 5-year survival rate of same postoperative pathology stage was not significantly different between two groups (I(-II( stage: RR=1.08, 95%CI:0.93-1.26, P=0.328; III(-IIII( stage: RR=0.59, 95%CI:0.33-1.04, P=0.111).

Conclusions: There are some different clinicopathological features between the generalized and the narrow GSC after gastric cancer surgery. The prognosis of GSC after radical resection is similar to primary proximal gastric cancer.