Primary central nervous system germ cell tumor (GCT) is relatively rare, accounting for only approximately 0.5% to 2.5% of all intracranial tumors. It is more prevalent in Asian countries than in Western countries [1]. GCT, along with gonadal germinoma, demonstrates a high responsiveness to both radiotherapy and chemotherapy. The 10-year overall survival (OS) rate following whole brain irradiation (WBI) or craniospinal irradiation (CSI) with a local boost range from 80% to 90%, Nevertheless, approximately 10-20% of patients experience recurrence following radiotherapy[2], [3]. Previous studies have reported certain prognostic factors for GCT such as human chorionic gonadotropin (HCG) level, and tumor size. However, the prognostic significance of these factors remains controversial, and currently, there are no established models for predicting long-term survival outcomes in GCT. Therefore, it is crucial to identify further potential prognostic factors and establish a precise and reliable prediction model to evaluate the prognosis of GCT patients before starting treatment.

Lactate dehydrogenase (LDH) plays a critical role as an enzyme in cellular energy metabolism. Tumor cells display a distinct metabolic activity, often characterized by increased anaerobic glycolysis, compared to normal cells. This metabolic pathway produces a substantial quantity of lactate, which is subsequently converted to pyruvate by LDH. Consequently, the expression of serum LDH levels is higher in tumor tissue than in normal tissue [4], [5]. LDH is currently acknowledged as a prognostic indicator for several malignant tumors, such as renal cell carcinoma, small-cell lung cancer, bladder cancer colorectal cancer, and testicular germ cell tumor [6], [7], [8], [9], [10]. However, there is a paucity of literature investigating the prognostic significance of serum LDH for GCT patients.

In this study, we conducted a single institution retrospective study of 161 patients with GCT treated with chemoradiotherapy to investigate the prognostic significance of LDH levels. Additionally, we constructed a risk score model that incorporates three prognostic factors to provide personalized management and predict the prognosis of GCT patients.