Malnutrition has been considered to be associated with the prognosis of cancer. the Geriatric nutritional Risk index (GnRi), based on serum albumin levels, present body weight, and ideal body weight, is a simple screening tool to predict the risk of nutrition-related morbidity and mortality in elderly patients. We aimed to evaluate whether preoperative GnRi was associated with postoperative complications and prognosis in elderly patients with colorectal cancer (cRc). We retrospectively enrolled 313 CRC patients aged ≥65 years after curative surgery and classified them into an all-risk GnRi (≤98) group and a no-risk GNRI (>98) group. Kaplan-Meier analysis showed overall survival was significantly worse in the all-risk GNRI group than in the no-risk GNRI group (P = 0.009). Multivariable analyses showed low GnRi (≤98) was an independent risk factor for postoperative complications (P = 0.048) and overall survival (P = 0.001) in the patients. Among the complications, the incidence of surgical site infection, in particular, was significantly higher in the all-risk GNRI group (P = 0.008). In conclusion, low preoperative GnRi (≤98) was associated with increased postoperative complications and poor prognosis. Preoperative GNRI can be used as an identifier for potential high-risk group of morbidity and mortality in elderly cRc patients. Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second leading cause of cancer-related mortality worldwide 1,2. According to the World Health Organization GLOBOCAN database, there were an estimated 1,849,518 new CRC cases and 880,792 CRC-related deaths in 2018 3. As life expectancy increases and the population ages, the number of elderly patients undergoing surgery also increases 4,5. For instance, in the United States, 60.7% of all the incident CRC patients in 2018 were 65 years or older, and then 81% of the elderly patients and even 64% of the patients aged ≥85 years underwent surgery from 2011 to 2015 3,6. Elderly patients often have some comorbidities, such as cardiovascular disease and respiratory dysfunction 7,8 , and often become malnourished 9,10. In elderly patients, disease-related malnutrition is associated with increased morbidity and mortality 9-12 and prolonged length of stay in hospital due to decrease in their life activity, performance status, and immune function 11-14. The Geriatric Nutritional Risk Index (GNRI) is an elderly-specific index that has been proposed to assess the nutrition-related risk of morbidity and mortality for elderly patients in hospital 15,16. This index was first reported by Bouillanne et al. They divided patients into four groups-a major-risk group (GNRI: <82), a moderate-risk group (GNRI: 82-<92), a low-risk group (GNRI: 92-98), and a no-risk group (GNRI: >98)-and suggested that the risk of infectious complications or mortality was significantly higher in the major-, moderate-, and low-risk groups than in the no-risk group 17. The GNRI is also used for prognosis of chronic diseases 18-20 , and in recent
