Changes in serum lactate dehydrogenase as a prognostic factor in patients with head and neck squamous cell carcinoma treated with immune checkpoint inhibitors.

BACKGROUND: Lactate dehydrogenase (LDH) is involved in the Warburg effect. Elevated serum LDH is a prognostic marker for metastatic solid cancer. AIM: To investigate the prognostic impact of serum LDH in patients with head and neck squamous cell carcinoma treated with immune checkpoint inhibitors (ICIs). MATERIALS AND METHODS: This retrospective study included 129 patients treated with ICIs between 2017 and 2023. The effects of pretreatment LDH, LDH at 3 months, and change in LDH during the first 3 months (ΔLDH) on overall survival (OS) and progression-free survival (PFS) were analyzed using the Kaplan-Meier method and Cox regression model. RESULTS: The 1-year PFS and OS rates for high and low groups were 6.0% and 30.1% for pretreatment LDH (p = 0.044), 25.7% and 38.3% for on-treatment LDH (p = 0.079), and 14.3% and 38.7% for ΔLDH (p = 0.008), as well as 42.1% and 60.9% for pretreatment LDH (p = 0.109), 56.0% and 80.5% (p < 0.001) for on-treatment LDH, and 31.0% and 81.0% for ΔLDH (p < 0.001), respectively. ΔLDH was an independent prognostic factor for both PFS and OS. CONCLUSIONS AND SIGNIFICANCE: ΔLDH can be used to predict ICI treatment outcomes and as a marker in deciding to continue ICI therapy.