The Geriatric Nutritional Risk Index is a prognostic marker in patients with metastatic colorectal cancer.

Background: The Geriatric Nutritional Risk Index (GNRI) is a nutritional index for elderly patients that is associated with prognosis in cancer patients. We investigated using the GNRI in patients with metastatic colorectal cancer to predict prognosis.

Methods: This study included 419 metastatic colorectal cancer patients who received first-line chemotherapy between February 2005 and December 2020. First, we calculated pre-treatment GNRI and divided the patients into four groups according to the values (G1-G4). We evaluated patient characteristics and overall survival in the four groups.

Results: Overall, 419 patients were included. The median follow-up was 34.4 months. Lower GNRI was positively associated with a lower grade Eastern Cooperative Oncology Group Performance Status (p = 0.009), synchronous metastases (p < 0.001), primary tumor resection prior to chemotherapy (p = 0.006), and did not undergo resection after chemotherapy (p < 0.001). Patients with low GNRI had significantly shorter overall survival than the group with high GNRI (median OS: G1 = 19.3 months [M], G2 = 30.8 M, G3 = 38 M, G4 = 39.7 M; log-rank test, p < 0.001). Multivariate Cox regression analysis showed that GNRI was an independent prognostic factor (G3: HR = 0.49, 95% CI = 0.35-0.69; G4: HR = 0.67, 95% CI = 0.48-0.93). In the subgroup analysis of overall survival, we found no interaction between clinicopathological factors and the prognostic value of GNRI. Interestingly, younger patients (< 70 years) but not older patients showed a significant difference in overall survival according to GNRI, despite being the metric being designed for elderly patients.

Conclusion: Pretreatment GNRI can be a prognostic marker for patients with mCRC who received systemic chemotherapy.