AIM: To re-evaluate the recent clinicopathological features of remnant gastric cancer (RGC) and to develop desirable surveillance programs.

METHODS: Between 1997 and 2008, 1149 patients underwent gastrectomy for gastric cancer at the Department of Digestive Surgery, Kyoto Prefectural University of Medicine, Japan. Of these, 33 patients underwent gastrectomy with lymphadenectomy for RGC. Regarding the initial gastric disease, there were 19 patients with benign disease and 14 patients with gastric cancer. The hospital records of these patients were reviewed retrospectively.

RESULTS: Concerning the initial gastric disease, the RGC group following gastric cancer had a shorter interval [P < 0.05; gastric cancer vs benign disease: 12 (2-22) vs 30 (4-51) years] and were more frequently reconstructed by Billroth-I procedure than those following benign lesions (P < 0.001). Regarding reconstruction, RGC following Billroth-II reconstruction showed a longer interval between surgical procedures [P < 0.001; Billroth-II vs Billroth-I: 32 (5-51) vs 12 (2-36) years] and tumors were more frequently associated with benign disease (P < 0.001) than those following Billroth-I reconstruction. In tumor location of RGC, after Billroth-I reconstruction, RGC occurred more frequently near the suture line and remnant gastric wall. After Billroth-II reconstruction, RGC occurred more frequently at the anastomotic site. The duration of follow-up was significantly associated with the stage of RGC (P < 0.05). Patients diagnosed with early stage RGC such as stage I-II tended to have been followed up almost every second year.

CONCLUSION: Meticulous follow-up examination and early detection of RGC might lead to a better prognosis. Based on the initial gastric disease and the procedure of reconstruction, an appropriate follow-up interval and programs might enable early detection of RGC.

The incidence of remnant gastric cancer (RGC) following distal gastrectomy has been reported to account for 1%-2% of all gastric cancers in Japan[1,2]. Previously, RGC was reported to be caused by multiple factors, and the incidence, pathological features, and potential mechanisms have been extensively investigated[3-5]. Specifically, RGC is commonly found at an advanced stage, resulting in low rates of curative resection (38%-40%) and a consequently poor prognosis[6,7]. However, recently, the incidence and etiology of RGC have been changing[8] because of the long latency periods, decreasing prevalence of gastrectomy for benign disease[6,9], early detection and improved outcomes in patients with gastric cancers[10,11]. Moreover, recent advances in diagnostic and treatment techniques have led to a higher detection rate of early RGC following distal gastrectomy[12]. Consequently, endoscopic therapy such as endoscopic mucosal resection or endoscopic submucosal dissection is applicable for treatment of early-stage RGC[13,14]. Indeed, more than half of the RGC patients were treated for T1 or T2, node-negative and early stage cancer at our institution and almost 80% of patients with RGC were curatively resected. Therefore, it is necessary to re-evaluate the risk factors of RGC to develop an optimal new surveillance program and treatment guide. However, there is limited information available to help guide the treatment of patients with RGC. This study was designed to re-evaluate the clinicopathological characteristics and surgical outcomes of RGC and to develop desirable surveillance programs.

Gastric cancer is the second leading cause of cancer-related death in the world[17]. However, recent advances in diagnostic methods, less invasive treatment techniques and better peri-operative management have increased the early detection of gastric cancer and decreased the mortality and morbidity rates[18-20]. Consequently, the number of cured patients has been increasing and some of these patients are at risk of acquiring second primary cancer in the remnant stomach. This implies that more cases of RGC will be encountered in the future.

In previous reports, RGC was commonly found at an advanced stage, resulting in low rates of curative resection (38%-40%) and a consequent poor prognosis[6,7]. However, recently, the incidence and etiology of RGC following distal gastrectomy may be changing due to diagnostic and technological advances. In our study, more than half of the RGC patients were treated for T1 or T2, node-negative and early stage cancer, contrary to that in previous series (Table 1). Almost 80% of patients were curatively resected with intensive lymphadenectomy. Thereby, the survival curves of primary proximal gastric cancer (PGC) and RGC were similar and without a significant difference, although patients with RGC tended to have a higher incidence of undifferentiated cancer, vascular invasion, and T4 component than patients with PGC (data not shown). Therefore, RGC is not always advanced at diagnosis and if so, intensive surgery for RGC does not necessarily mean a poor prognosis in comparison to that for primary gastric cancer. Therefore, it is necessary to re-evaluate the risk factors of RGC to develop an optimal new endoscopic surveillance program and treatment guide.

Regarding surveillance systems for early detection and curative treatment of RGC, periodic endoscopic examinations of the gastric remnant are shown to be extremely important in our study (Figure 1). However, a follow-up program that is too intensive may not be beneficial to the patient. The initial gastric disease and the interval between the 1st and 2nd surgery could affect the incidence of RGC. In our study, RGC following gastric cancer had a significantly shorter interval between 1st and 2nd surgery than that following benign disease [P < 0.05; gastric cancer vs benign disease: 12 (2-22) years vs 30 (4-51) years]. However, surveillance systems for gastric cancer should be especially considered because of decreasing gastrectomy for benign disease. Furthermore, 86% of all initial gastric cancer patients underwent Billroth-I reconstruction at our institution and their median interval between 1st and 2nd surgery was 12 (2-36) years. Moreover, the duration of follow-up was significantly associated with the stage of RGC progression and an early detection of RGC led to better prognosis (Figure 2). Taken together, annual surveillance endoscopic screening should be required for at least 12 years following distal gastrectomy. Furthermore, after 12 years of follow-up, surveillance endoscopy should be recommended every second year because we found that patients diagnosed with early stage RGC such as stage I-II tended to have been followed almost every second year. In particular, meticulous endoscopy examination should be performed near the suture line and remnant gastric wall after Billroth-I reconstruction and also should be performed at the anastomotic site after Billroth-II reconstruction.

In conclusion, due to recent advances in diagnostic and treatment technologies, the etiology of RGC has been changing. Meticulous follow-up examination and early detection of RGC might lead to a better prognosis. Considering both the initial gastric disease and the procedure of reconstruction, an appropriate follow-up interval and programs should facilitate the detection of early RGC.