Risk factors of gastric remnant cancer: a meta-analysis and systematic review

Aim: To investigate the risk factors of gastric remnant cancer. Methods: A search on PubMed, Embase, ISI Web of SCIENCE, Cochrane Library, CNKI, and Wanfang was performed to identify relevant literature published from January 1990 to May 2014. The effect of gastric remnant cancer was estimated by risk ratio (RRs) with 95% confidence intervals (CIs) for each study using a fixed effects or random effects model. Results: 28 studies with a total of 1132 patients met the inclusion criteria in our study. The risk for gastric remnant cancer was positively associated with a male gender, an initial ulcerative disease, a previous Billroth II anastomosis. Gastric remnant cancer was also more likely to be located at the site of initial anastomosis and was associated with a poorly differentiated and/or undifferentiated histology. However no significance was observed between the TNM stage and the gastric remnant cancer. Conclusion: Meta-analysis found that gastric remnant cancer is associated with gender, reason for initial surgery, type of initial surgery performed, location, histology. Introduction As first described by Balfour in 1922, Gastric Remnant Cancer (GRC), is a cancer in the remnant stomach occurring at least 5 years after a partial gastrectomy [1]. The latter is usually performed for Peptic Ulcer Disease (PUD) or Gastric Cancer (GC) resection. Even though the incidence of partial gastrectomy for PUD and GC is decreasing, more patients are being diagnosed with GRC [1]. GRC has been reported to have a poor prognosis. This is usually due to the advanced stage of the disease at the time of diagnosis. Often, patients are found to present with both lymph node metastasis and invasion to adjacent organs [2]. It is therefore essential to identify high risk patients who would benefit from surveillance.Even though previous studies have identified several risk factors of GRC, the results remain controversial and hence inconclusive. An earlier meta-analysis reported gastric ulcer patients had a higher risk than duodenal ulcer patients of developing GRC after the surgical therapy [3]. However, during the past few years more risk factors have been observed. Herein, we performed an updated metaanalysis of the existing literature published in both English language and Chinese language from January 1990 to May 2014. We defined GRC as a cancer occurring in the remnant stomach at least 5 years after a partial gastrectomy irrespective of whether the resection was due to a benign or malignant disease. The timeframe of 5 years is of utmost importance in order to ensure the cancer of the remnant stomach is not due to remaining cancer of the initial disease. We herein assess the likelihood of a patient developing GRC and hence define high risk patients who would be appropriate for surveillance. Materials and methods Search strategy and selection criteria We searched PubMed, Embase, ISI Web of SCIENCE and Cochrane Library in English, and CNKI and Wanfang in Chinese to identify relevant literature published in English language from January 1990 to May 2014. The following keywords were used: “gastric remnant cancer”, “gastric remnant carcinoma”, “gastric stump cancer”, “gastric stump carcinoma”. The reference lists of the retrieved studies were also hand-searched for additional articles. Inclusion and exclusion criteria All included studies were about GRC or gastric stump cancer. Only full-text literatures were included. The selected studies had data on at least one of the following: gender, reason for initial surgery, type of surgery performed during the initial surgery, location of GRC, GRC histology. Excluded studies were of studies not meeting the definition of GRC, literature published before January 1990, case reports, GRC reviews, and other meta-analyses. Studies in which the data could not Correspondence to: Zuli Yang, Department of Gastrointestinal Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, 26 Yuancun Erheng Road, Guangzhou 510655, P.R. China, Tel: +86 20 38455479; Fax: +86 20 38254221; E-mail: [email protected]