Perioperative IDO-1 dynamic changes in NSCLC patients.

Abstract

e20532 Background: Indoleamine 2,3-dioxygenase (IDO) is an enzyme that is involved in the metabolism of tryptophan, an essential amino acid. It is known to play a role in the regulation of the immune system, and has been linked to perioperative immune status. Specifically, IDO has been shown to be upregulated in the perioperative period, leading to an increased risk of infection and other complications. This is thought to be due to the increased production of kynurenine, a metabolite of tryptophan, which has been associated with immunosuppression. Additionally, IDO has been linked to increased levels of inflammation and oxidative stress, which can further contribute to the risk of complications during surgery. Thus, understanding the role and dynamic changes of IDO in the perioperative period is important for optimizing patient outcomes. Methods: Patients with non-small cell lung cancer (NSCLC) who underwent surgery were enrolled in this study prospectively. Peripheral blood at different time points: preoperative, post anesthesia, post-vascular incision, post-tumor resection, and 3 days after surgery. The serum tryptophan and kynurenine were measured, and the kynurenine to tryptophan (K:T) ratio was used as an indicator of IDO activity. Paired Wilcoxon test was used to identify the significant difference of IDO activity at five different time points. The Kaplan–Meier log-rank test was used to assess the correlation between overall survival (OS), progression-free survival (PFS), and IDO activity. Results: A total of 46 patients were enrolled in this study. The median follow-up time was 24.7 (range: 0.9 – 35.3) months. No patients died during the follow-up time. The PFS at 2 years was 76% (95% CI, 76%-100%). In all patients, IDO activity was not correlated significantly with better PFS. Surgical procedure does not affect levels of plasma IDO at any pathological stage in NSCLC significantly. The level of serum IDO of post-vascular incision was significantly correlated with that of 3 days after surgery (R2 = 0.7, P < 0.05). The level of preoperative level of serum kynurenine was significantly correlated with that of post-vascular incision and post-tumor resection (R2 = 0.7/0.73, P < 0.05). Conclusions: Surgical procedure does not have a significant effect on the serum IDO levels during the perioperative period. The perioperative levels of serum IDO are not correlated with the surgical prognosis of NSCLC, thus alternative markers are needed to better predict the surgical prognosis of NSCLC patients.