Comparison of neoadjuvant chemotherapy and postoperative adjuvant chemotherapy in the treatment of Borrmann type IV gastric cancer.

e16064 Background: Borrmann type IV gastric cancer is highly malignant and prone to peritoneal metastasis, including peritoneal dissemination (P1) and positive peritoneal cytology (CY1) causing a dismal prognosis. This study is to compare the efficacy of neoadjuvant chemotherapy and postoperative adjuvant chemotherapy in patients with Borrmann type IV gastric cancer and analyze the prognostic factors of these patients. Methods: According to different therapies, patients diagnosed with Borrmann type IV gastric cancer in Zhejiang Cancer Hospital from June 2010 to June 2020, were divided into two groups: neoadjuvant chemotherapy group (NCT group) and non-neoadjuvant chemotherapy group (NNCT group). Both of two groups were subjected to the propensity score matching (PSM) at a ratio of 1:2 and then the treatment completion rate and overall survival (OS) time were analyzed. Results: A total of 240 cases were included after propensity score matching and 80 patients and 160 patients were enrolled in the NCT group and NNCT group, respectively. Neoadjuvant chemotherapy and postoperative adjuvant chemotherapy were based on platinum combined with fluorouracil. For the efficacy of treatment, R0 resection was performed on 92.2% patients in the NCT group and 88.1% in the NNCT group, but there was no statistical difference (P=0.463). 3-year survival rate was 35.0% in the NCT group compared with 29.4% in the NNCT group (P=0.427), and the 5-year survival rate was 28.7% and 25.6%, respectively (P=0.460). For patients with and without R0 resection, the 3-year survival rate was 34.3% and 7.4% (P<0.001), and the 5-year survival rate was 30.0% and 0%, respectively (P<0.001). Hyperthermic intraperitoneal chemotherapy (HIPEC) was conducted on 40 patients (16.7%), and the survival rate of HIPEC group was better than that of non-HIPEC group (3 year survival rate: 55.0% vs 26.5%, P=0.073; 5 year survival rate: 45.0% vs 23.0%, P=0.174), but the difference was not statistically significant. Conclusions: Borrmann type IV gastric cancer was characterized by poor differentiation and high incidence of peritoneal metastasis. The efficacy of the neoadjuvant chemotherapy based on platinum combined with fluorouracil is limited. A combination of HIPEC and system chemotherapy may effectively improve the prognosis of these patients.