BackgroundTo investigate the incidence, causes and risk factors for unplanned reoperation because of early complications within 30 days of radical gastrectomy for gastric cancer.MethodsThe study cohort comprised 1,948 patients who underwent radical gastrectomy for gastric cancer between November 2010 and April 2017. The incidence, causes and outcomes of unplanned reoperation were examined and the risk factors were identified using univariate and multivariate analyses.ResultsIn total, 24 patients (1.2%) underwent unplanned reoperations because of early complications after radical gastrectomy. The main causes more frequently requiring reoperation were adhesive intestinal obstruction (eight cases, 33.3%), intra-abdominal bleeding (five cases, 20.8%), wound dehiscence (five cases, 20.8%), anastomotic leakage and intra-abdominal infection (five cases, 20.8%), and iatrogenic common bile duct injury (one case). Multivariate analysis identified that only combined multi-organ resection (odds ratio (OR) = 4.060, 95% confidence interval (CI): 1.645 - 10.023, P = 0.002) was an independent risk factor. Two patients (8.3%) who underwent reoperation died from disseminated intravascular coagulation or sepsis, respectively, which was significantly higher than the remaining 1,924 patients who did not require reoperation (six cases, 0.3%, P < 0.001). Moreover, patients who underwent reoperation experienced higher morbidity rates (37.5% vs. 6.8%, P < 0.001), requiring intensive care (20.8% vs. 2.4%, P < 0.001) and longer postoperative hospital stays (33.6 days vs. 11.0 days, P < 0.001) compared with patients required no reoperation.ConclusionsCombined multi-organ resection was an independent risk factor for unplanned reoperation following radical gastrectomy. Avoiding multi-organ resection as possible will decrease the likelihood of patients requiring reoperation.