Peripheral blood nutrient indices as biomarkers for anti‑PD‑1 therapy efficacy and prognosis in patients with advanced gastric cancer.

Immunotherapy offers survival benefits for patients with advanced gastric cancer, but not all populations can benefit from immunotherapy. Good nutritional status is fundamental to a patient's immune function and may have an impact on the efficacy of immunotherapy. The present study aimed to investigate changes in prognostic nutritional index (PNI), advanced lung cancer inflammation index (ALI) and albumin-globulin ratio (AGR) values before and after immunotherapy in patients with advanced gastric cancer. The study also aimed to determine the potential association of the aforementioned values with patient outcomes and prognosis. Body mass index (BMI), serum albumin, total protein, peripheral blood lymphocyte, neutrophil, carcinoembryonic antigen (CEA), carbohydrate antigen19-9 (CA19-9) and a-fetoprotein (AFP) data were collected from 195 patients with advanced gastric cancer who underwent immunotherapy from January 2020 to October 2021. In addition, PNI, ALI and AGR values were calculated based on variables in blood collected from the patients within 3 days prior to immunotherapy and 3 weeks after immunotherapy. The results demonstrated that low PNI was associated with elevated CEA levels. Moreover, low ALI levels were associated with reduced BMI levels, elevated AFP levels, PD-L1 negative and first-line treatment. Comparison of responding and non-responding groups revealed that patients who responded to immunotherapy had higher PNI and AGR values than patients who did not respond, both before and after treatment, but had lower CEA and CA19-9 levels after treatment. Furthermore, in the non-responding group, PNI and AGR values were decreased and CEA values were increased following treatment compared with those prior to treatment. The objective response and disease control rates were higher in the high PNI and AGR groups compared with the low PNI and AGR groups, respectively. Moreover, PNI and AGR were found to be independent predictors of the short-term efficacy of immunotherapy for advanced gastric cancer, with cut-off values of 47.18 and 1.29, respectively. Univariate analysis revealed that ALI was associated with the progression-free survival (PFS) of patients, while multivariate analysis demonstrated that baseline PNI and AGR were independent predictors of PFS. In conclusion, tumor progression leads to a decline in the nutritional level of patients, and the present study indicated that effective immunotherapy may alleviate this deterioration to a certain extent. Furthermore, PNI and AGR exhibit potential in predicting the efficacy of immunotherapy and the prognosis of patients with advanced gastric cancer, and may exhibit potential as biomarkers in clinical practice.