Dynamic evolution of circulating tumor dna in patients with hepatocellular carcinoma across tumor stages and treatments

Background Circulating tumor DNA (ctDNA) is a promising non-invasive biomarker in cancer management. We aimed to assess the dynamic evolution of ctDNA in patients with hepatocellular carcinoma (HCC). Methods 832 plasmas collected in 173 patients with HCC and 56 patients with chronic liver diseases without HCC were studied. We evaluated the quantity of cell free DNA (cfDNA) and search for mutations in TERT promoter (TERTp.), CTNNB1, TP53, PIK3CA and NFE2L2 by ultra-deep next generation sequencing and for TERTp. by digital droplet PCR. Results Among the 173 HCC patients (82% male, median age 63y), 73% had cirrhosis. Among the 776 plasmas of patients with HCC, 502 were collected in patients with an active HCC (aHCC), 158 24 hours after a locoregional treatment (H24) and 116 in patients with a past history but without active HCC at sampling (iHCC). Median cfDNA quantity was higher in aHCC than iHCC (0.27 vs 0.16 ng/µL, p<0.001). Within the 502 aHCC plasmas we identified mutations in 46% of them: TP53 (29%), TERTp. (27%), CTNNB1 (13%), PIK3CA (0.4%) and NFE2L2 (0.2%). CfDNA mutation rate increased across tumor stages (16% BCLC 0,25% BCLC A, 42% BCLC B and 58% BCLC C; p<0.001). The presence of mutations, particularly in the TERTp. and TP53, was associated with OS-RFS/PFS, both when considering all plasma samples and in the analysis of various treatment subgroups. Regarding H24 plasmas an increase in cfDNA level (0.19 before vs 0.63 after, p<0.001) and in mutation rate (31% vs 44%, p<0.001) was observed. Finally, a total of 179 plasmas in 50 patients treated by atezolizumab/bevacizumab were analyzed. Baseline cfDNA mutations were observed in 49% of cases. Mutations in cfDNA observed at baseline disappeared in all patients with a response at 12 weeks. In contrast, persistence of mutations under treatment was significantly associated with progression (p=0.005). Conclusion Circulating tumor DNA offers dynamic information about tumor biology representing a non-invasive tool potentially useful to guide HCC clinical management. Circulating tumor DNA (ctDNA) is a promising non-invasive biomarker in cancer management. We aimed to assess the dynamic evolution of ctDNA in patients with hepatocellular carcinoma (HCC). 832 plasmas collected in 173 patients with HCC and 56 patients with chronic liver diseases without HCC were studied. We evaluated the quantity of cell free DNA (cfDNA) and search for mutations in TERT promoter (TERTp.), CTNNB1, TP53, PIK3CA and NFE2L2 by ultra-deep next generation sequencing and for TERTp. by digital droplet PCR. Among the 173 HCC patients (82% male, median age 63y), 73% had cirrhosis. Among the 776 plasmas of patients with HCC, 502 were collected in patients with an active HCC (aHCC), 158 24 hours after a locoregional treatment (H24) and 116 in patients with a past history but without active HCC at sampling (iHCC). Median cfDNA quantity was higher in aHCC than iHCC (0.27 vs 0.16 ng/µL, p<0.001). Within the 502 aHCC plasmas we identified mutations in 46% of them: TP53 (29%), TERTp. (27%), CTNNB1 (13%), PIK3CA (0.4%) and NFE2L2 (0.2%). CfDNA mutation rate increased across tumor stages (16% BCLC 0,25% BCLC A, 42% BCLC B and 58% BCLC C; p<0.001). The presence of mutations, particularly in the TERTp. and TP53, was associated with OS-RFS/PFS, both when considering all plasma samples and in the analysis of various treatment subgroups. Regarding H24 plasmas an increase in cfDNA level (0.19 before vs 0.63 after, p<0.001) and in mutation rate (31% vs 44%, p<0.001) was observed. Finally, a total of 179 plasmas in 50 patients treated by atezolizumab/bevacizumab were analyzed. Baseline cfDNA mutations were observed in 49% of cases. Mutations in cfDNA observed at baseline disappeared in all patients with a response at 12 weeks. In contrast, persistence of mutations under treatment was significantly associated with progression (p=0.005). Circulating tumor DNA offers dynamic information about tumor biology representing a non-invasive tool potentially useful to guide HCC clinical management.