Personalized circulating tumor DNA in patients with hepatocellular carcinoma: a pilot study.

BACKGROUND: Mutational analysis of circulating tumor DNA (ctDNA) can potentially be used for early detection of recurrence after resection for hepatocellular carcinoma (HCC). Mutations from tumor may be identified in plasma as an early sign of recurrence. We conducted a pilot study investigating if somatic mutations could be detected in plasma in patients undergoing liver resection for HCC and in patients with advanced non-resectable HCC. METHODS AND RESULTS: We prospectively included patients undergoing curative liver resection for HCC. Tumor tissue was investigated with whole exome sequencing and preoperative blood samples were evaluated for ctDNA using targeted next-generation sequencing (NGS) with TruSight Oncology 500 including 523 cancer-associated genes. Subsequently, the method was evaluated in patients with advanced HCC. We included eight patients curatively resected for HCC, where tumor tissue mutations were identified in seven patients. However, only in one patient tumor specific mutations were found in the preoperative blood sample. In all three patients with advanced HCC, tumor mutations were detected in the blood. CONCLUSIONS: In patients with resectable HCC, ctDNA could not be reliably detected using the applied targeted NGS method. In contrast, ctDNA was detected in all patients with advanced HCC. Small tumors, tumor heterogeneity and limited sequencing coverage may explain the lack of detectable ctDNA.