Co-relation of Portal Vein Tumour Thrombus Response With Survival Function Following Robotic Radiosurgery in Vascular Invasive Hepatocellular Carcinoma.

The aim of this study was to prospectively evaluate stereotactic body radiotherapy (SBRT) with robotic radiosurgery in hepatocellular carcinoma patients with macrovascular invasion (HCC-PVT). Patients with inoperable HCC-PVT, good performance score (PS0-1) and preserved liver function [up to Child-Pugh (CP) B7] were accrued after ethical and scientific committee approval [Clinical trial registry-India (CTRI): 2022/01/050234] for treatment on robotic radiosurgery (M6) and planned with Multiplan (iDMS V2.0). Triple-phase contrast computed tomography (CT) scan was performed for contouring, and gross tumour volume (GTV) included contrast-enhancing mass within main portal vein and adjacent parenchymal disease. Dose prescription was as per risk stratification protocol (22–50 Gy in 5 fractions) while achieving the constraints of mean liver dose <15 Gy, 800 cc liver <8 Gy and the duodenum max of <24 Gy). Response assessment was done at 2 months' follow-up for recanalization. Patient- and treatment-related factors were evaluated for influence in survival function. Between Jan 2017 and May 2022, 318 consecutive HCC with PVT patients were screened and 219 patients were accrued [male 92%, CP score: 5–7 90%, mean age: 63 years (38–85 yrs), Cancer of the Liver Italian Program <3: 84 (40%), 3–6117 (56%), infective aetiology 9.5%, performance status (PS): 0–37%; 1–56%]. Among 209 consecutive patients accrued for SBRT treatment (10 patients were excluded after accrual due to ascites and decompensation), 139 were evaluable for response assessment (>2 mo follow-up). At mean follow-up of 12.21 months (standard deviation: 10.66), 88 (63%) patients expired and 51 (36%) were alive. Eighty-two (59%) patients had recanalization of PVT (response), 57 (41%) patients did not recanalize and 28 (17%) had progressive/metastatic disease prior to response evaluation (<2 months). Mean overall survival (OS) in responders and non-responders were 18.4 [standard error (SE): 2.52] and 9.34 month (SE 0.81), respectively (P < 0.001). Mean survival in patients with PS0, PS1 and PS2 were 17, 11.7 and 9.7 months (P = 0.019), respectively. OS in partial recanalization, bland thrombus and complete recanalization was 12.4, 14.1 and 30.3 months, respectively (P -0.002). Adjuvant sorafenib, Barcelona Clinic Liver Classification stage, gender, age and RT dose did not influence response to treatment. Recanalization rate was higher in good PS patients (P -0.019). OS in patients with response to treatment, in those with no response to treatment, in those who are fit but not accrued and in those who are not suitable were 18.4, 9.34, 5.9 and 2.6 months, respectively (P -<0.001). Thirty-six of 139 patients (24%) had radiation-induced liver disease (RILD) [10 (7.2%) had classic RILD & 26 (19%) had non-classic RILD]. Derangement in CP score (CP score change) by more than 2 was seen in 30 (24%) within 2-month period after robotic radiosurgery. Eighteen (13%) had unplanned admissions, two patients required embolization due to fiducial-related bleeding and 20 (14%) had ascites, of which 9 (6%) patients required abdominocentesis. PVT response or recanalization after SBRT is a statistically significant prognostic factor for survival function in HCC-PVT. [ABSTRACT FROM AUTHOR]