Low applicability of the ''Six-and-twelve score" in hepatocellular carcinoma treated with Drug-Eluting Beads Transarterial Chemoembolization.

Objective: The effectiveness of transarterial chemoembolization (TACE) in hepatocellular carcinoma (HCC) depends on the selection of suitable patients. The ''Six-and-twelve score" distinguishes three groups of ideal patients with different overall survival, based on the sum of the number and size of tumors. This may impact on clinical practice and trial design. The aim of this study was to assess the reproducibility and prognostic value of the model in western patients treated with Drug-Eluting Beads (DEB)-TACE.

Methods: Observational, retrospective, unicentric study with consecutive compensated patients treated with DEB-TACE from October 2008 to October 2017. Exclusion criteria were Child-Pugh ≥ 8 and DEB-TACE used as a bridge to liver transplantation.

Results: 225 HCC consecutive patients were included; BCLC-0/A n=131 (single nodules > 5, n=29) and BCLC-B n=94. The median overall survival (OS) was 27 months (95% CI 23.8-30.2). OS was different between BCLC-0/A vs BCLC-B: 30 vs 24 months (p= 0.03), Child-Pugh A5 vs A6-B7: 30 vs 27 months (p= 0.003). ''Six-and-twelve score" groups discriminated OS: group 1, n=123, 32 months (95% CI 27.5-63.5), group 2, n=101, 24 months (95% CI 19.6-28.4) and group 3, n=1, 27 months (p=0.024). When comparing the three scores, the ''Six-and-twelve score" showed the best discrimination power: C-index 0.603, Akaike's information criterion (AIC) 1.642, likelihood ratio test (LRT) 16.21.

Conclusion: The ''Six-and-twelve score" is a prognostic tool for patients with HCC treated with DEB-TACE. However, few patients were included in the third group (score >12) and no differences were observed with BCLC, therefore its applicability is limited.  .