Liver regeneration after radiotherapy in patients with hepatocellular carcinoma: A simple-to-use model and nomogram.

Abstract

e16115 Background: In the past clinical practice of radiotherapy for liver cancer, liver regeneration (LR) which is beneficial to the prevention or recovery of radiation-induced liver injury, has not received enough attention. In current study, we aimed to build and validate multivariate model for liver regeneration after radiation therapy for hepatocellular carcinoma (HCC) based on data from 2 prospective studies. Methods: Thirty patients treated with preoperative downstaging radiotherapy were prospectively included in the training cohort, and 21 patients treated with postoperative adjuvant radiotherapy were included in the validation cohort. Liver regeneration was defined as an increase of more than 10% of normal liver volume in the areas of the protected hepatic segment or lobe, without Child-Pugh class decreased and tumor progression compared to pre-radiotherapy. Model and nomogram of liver regeneration after radiotherapy were developed and validated. The cut-off points of each optimal predictors were obtained using receiver-operating characteristic analysis. Risk stratification based on the cut-off point was conducted to compare the proportion of patients with liver regeneration between subgroups. Results: After radiotherapy, 12 (40%) cases in the training cohort and 13 (61.9%) cases in the validation cohort experienced liver regeneration. The model and nomogram of liver regeneration based on SVs20 (standard residual liver volume spared from at least 20 Gy) and alanine aminotransferase (ALT) showed good prediction performance (AUC = 0.759) in training cohort and performed well (AUC = 0.808) in the validation cohort. The risk stratification according to the cutoffs of SVs20 with 303.4 mL and ALT with 43 U/L demonstrated clear differentiation in risk of liver regeneration between the training(P = 0.049) and entire cohort (P = 0.032). The proportion of patients with liver regeneration decrease progressively with 88.9% in high-probability group (ALT＜43 U/L and SVs20＜303.4 mL), 60% in high-intermediate probability group (ALT ≥43 U/L and SVs20＜303.4 mL), 43.75% in low-intermediate probability group (ALT＜43 U/L and SVs20≥303.4 mL) and 33% in low- probability group (ALT≥43 U/L and SVs20≥303.4 mL). Conclusions: SVs20 and ALT are optimal predictors for liver regeneration. This simple-to-use nomogram is beneficial to the constraints of normal liver outside the radiotherapy target area and make prognosis-based decision without complex calculations. Clinical trial information: ChiCTR1800015350. [Table: see text]