Systemic immune-inflammation index in germ-cell tumours: search for a biological prognostic biomarker

Germ-cell tumours (GCTs) are collectively the most common cancer type in men aged 15–40 years, and they are a significant cause of morbidity and mortality in this population. Platinum-based chemotherapy has dramatically improved the outcome for patients with metastatic disease since the first patient was treated at Indiana University in 1974 ( Einhorn & Donohue, 1977 ); however, despite the high cure rate of 70–80%, ∼ 20–30% of patients with metastatic disease will relapse after first-line chemotherapy ( Albany et al, 2017a ). The International Germ-Cell Cancer Collaborative Group (IGCCCG) classifies patients with metastatic GCT into good, intermediate, and poor risk groups based on three clinical prognostic criteria: primary tumour site, metastatic sites, and the amplitude of serum tumour marker levels ( IGCCCG, 1997 ). However, these IGCCCG prognostic criteria are merely a reflection of the volume of disease rather than the pathology. Currently, no biological prognostic serum biomarker exists for this disease beyond the serum tumour markers alpha-fetoprotein (AFP) and beta-subunit of human chorionic gonadotropin (hCG), and these two markers do not predict who will relapse after chemotherapy. For example, patients with elevated AFP (>10 000 ng/ml) or hCG (>50 000 IU/L) are classified as poor-risk, with a 50% chance of cure following four cycles of bleomycin, etoposide and platinum (BEP) chemotherapy; however, we cannot predict whether a particular patient will respond to this chemotherapy. Thus, a biologically driven biomarker that reflects the pathogenesis is highly needed.