Abstract:Objective To explore the efficacy of tislelizumab combined with pemetrexed and carboplatin chemotherapy in elderly patients with advanced lung adenocarcinoma and its effects on serum insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) levels. Methods Ninety-four driver gene-negative elderly patients with advanced lung adenocarcinoma admitted to the Fourth Affiliated Hospital of Nanjing Medical University from July 2021 to December 2022 were selected as the study subjects. They were divided into chemotherapy group (pemetrexed combined with carboplatin, n=48) and tislelizumab group (pemetrexed+carboplatin+tislelizumab, n=46) by the random number table method, and both groups were treated for 4 cycles, with 21 days as a cycle. The clinical efficacy, immune function ［T lymphocyte subsets (CD4 ⁺, CD8 ⁺, CD4 ⁺/CD8 ⁺)］ and serum indicators (IGF-1, IGFBP-3) before and after treatment were recorded in both groups, and the adverse reactions were assessed. Results The clinical efficacy and objective response rate (58.70% vs 29.17%, χ²=8.329, P＜0.01) in tislelizumab group were significantly higher than those in chemotherapy group. After 4 cycles of treatment, the CD4 ⁺, CD4 ⁺/CD8 ⁺ and IGFBP-3 levels in both groups were significantly increased compared with those before treatment (P＜0.05), and the indicators in tislelizumab group were higher than those in chemotherapy group (P＜0.05); CD8 ⁺ and IGF-1 levels were significantly decreased in both groups compared with those before treatment (P＜0.05), and the indicators in tislelizumab group were lower than those in chemotherapy group (P＜0.05). Adverse reactions were mainly grade 1-2 in both groups, and there was no significant difference in the incidence of adverse reactions between two groups (P＞0.05). Conclusion The first-line therapy of tislelizumab combined with platinum-containing dual-drug for elderly advanced lung adenocarcinoma can improve the clinical efficacy, improve the balance of CD4 ⁺/CD8 ⁺, regulate the expression of serum IGF-1 and IGFBP-3 levels. The adverse reactions are controllable, and the treatment regimen is safe and reliable.