Association Between Khorana Score and Prognosis in Cancer Patients With Stage IV Treated With Immune Checkpoint Inhibitors ~ Factor Analysis in Khorana Score Related to Overall Survival ~

Takayuki IdeTaisuke ArakiTomonobu Koizumi^*

• Shinshu University Hospital, Matsumoto, Japan

Purpose The Khorana venous thromboembolism risk assessment score (Khorana score) is an established tool for risk stratification of thromboembolism in patients with cancer. There have been few reports on the relation between Khorana score and prognosis in patients after treatment with immune checkpoint inhibitors (ICIs). The present study was performed to evaluate the association between prognosis and Khorana score in patients with stage IV cancer treated with ICIs. Methods We conducted a retrospective chart survey of patients receiving at least one ICI at Shinshu University Hospital between September 2014 and October 2021. Age, sex, cancer type, body mass index, laboratory data at commencement of treatment, and patient outcomes were obtained from electronic medical records. Khorana score was calculated based on cancer type and biomarkers. Results The study population consisted of 407 patients (71.0% men) with a median age of 70.0 years (interquartile range [IQR], 63.0–76.0) and a median follow-up of 15.1 months (range, 0.16-72.0). Nivolumab was the most commonly used ICI (60.4%). The median survival time (MST) for all patients was 17.5 months (95% CI, 14.4-20.8). There were significant differences in MST between the low-risk, intermediate-risk and high-risk groups according to Khorana score (p < 0.001, p = 0.022, respectively). With regard to each component of the Khorana score, exploratory univariate analysis of risk factors revealed significant differences in white blood cell (WBC) count, hemoglobin (Hb) level, and some cancer types (p = 0.009, p < 0.001, and p = 0.006, respectively). Hb level < 10 g/dL was identified as a risk factor on the Cox proportional hazards regression analysis (Hazard Ratio, 1.78; 95% CI, 1.21-2.60; p = 0.003). Conclusion Our results suggested that Khorana score at the start of ICIs treatment was related to prognosis of patients with stage IV cancer. In particular, Hb level < 10 g/dL before commencement of treatment was shown to be an independent risk factor affecting prognosis.