Abstract
BACKGROUND: Octamer-binding transcription factor 4-positive circulating tumor cell (OCT4(+)CTC) exhibits high stemness and invasive potential, which may influence the efficacy of immune checkpoint inhibitors (ICI). This study aimed to assess the prognostic role of OCT4(+)CTC in advanced cholangiocarcinoma (CCA) patients who received ICI treatment. METHODS: In total, 40 advanced CCA patients who received ICI treatment were included, and CTC and OCT4 counts were detected via a Canpatrol system and an RNA in situ hybridization method before ICI treatment. Patients were subsequently divided into none CTC, OCT4(-)CTC, and OCT4(+)CTC groups. Patients were followed up for a median of 10.4 months. RESULTS: The percentages of patients in none CTC, OCT4(-)CTC, and OCT4(+)CTC groups were 25.0%, 30.0%, and 45.0%, respectively. The proportion of patients with lymph node metastasis was highest in OCT4(+)CTC group, followed by none CTC group, and lowest in OCT4(-)CTC group (P = 0.025). The objective response rate (ORR) was lowest in OCT4(+)CTC group, moderate in OCT4(-)CTC group, and highest in none CTC group (P = 0.009), while disease control rate was not different among three groups (P = 0.293). In addition, progression-free survival (PFS) (P < 0.001) and overall survival (OS) (P = 0.001) were shorter in the OCT4(+)CTC group than in none CTC & OCT4(-)CTC group. Moreover, OCT4(+)CTC (versus none CTC) was independently linked with poorer PFS [hazard ratio (HR) = 6.752, P = 0.001] and OS (HR = 6.674, P = 0.003) in advanced CCA patients. CONCLUSION: OCT4(+)CTC relates to lymph node metastasis and shows a good predictive value for poor treatment response and survival in advanced CCA patients who receive ICI treatment.