Abstract: Objective To investigate the effect of geriatric nutritional risk index (GNRI) on postoperative complications and prognosis of elderly patients with gastrointestinal tumor. 
Methods A total of 255 elderly patients with gastrointestinal tumor(age ≥ 65 years) were divided into normal GNRI group(GNRI ＞ 98) and abnormal GNRI group(GNRI ≤ 98), including 85 elderly patients with liver cancer(70 in normal GNRI group and 15 in abnormal GNRI group), 90 elderly patients with esophageal squamous cell carcinoma(ESCC)(70 in normal GNRI group and 20 in abnormal GNRI group), and 80 elderly gastric cancer patients(60 in normal GNRI group and 20 in abnormal GNRI group). According to the inclusion and exclusion criteria, the clinical data of patients were collected and analyzed retrospectively. The survival rate was calculated by Kaplan Meier method, and the survival rate was compared by Log-rank test. The impact of GNRI on postoperative complications and prognosis of elderly cancer patients was evaluated. 
Results Within two months after liver cancer operation, 23 patients(27.06%) had complications. Body mass index(BMI), duration of operation, albumin content and GNRI were the risk factors for postoperative complications in patients with liver cancer. The 1, 3 and 5-year survival rates of normal GNRI group(n=15) were 82.85%, 68.57% and 57.14%, respectively, which were significantly better than those(73.33%, 53.33%, 40.00%) of abnormal GNRI group(n=70), and the difference was statistically significant(P＜0.05). Within two months after operation for ESCC, 29 patients(32.22%) had complications. BMI, FVE 1.0% and GNRI were the risk factors for postoperative complications of ESCC. The 1, 3 and 5-year survival rates of normal GNRI group(n=70) were 85.71%, 71.43% and 55.71%, respectively, which were significantly higher than those(75.00%, 55.00%, 40.00%) of abnormal GNRI group(n=20), and the difference was statistically significant(P＜0.05). Within two months after operation for gastric cancer, 16 patients(20.00%) had complications. BMI, arrhythmia and GNRI were the risk factors for postoperative complications in patients with gastric cancer. The 1, 3 and 5-year survival rates of normal GNRI group(n=60) were 83.33%, 70.00% and 58.33%, respectively, which were significantly higher than those in abnormal GNRI group(n=20), and the difference was statistically significant(P＜0.05). 
Conclusion Preoperative GNRI is related to the biological behavior of elderly patients with gastrointestinal cancer, which can be used to effectively predict the postoperative complications and survival rate.

Key words: liver neoplasms, esophageal neoplasms, gastric neoplasms