Patterns of care and outcome of liver SBRT: results from a multicentre National quality project

Stereotactic body radiotherapy (SBRT) is applied for both primary liver tumours and liver metastases. Within a national project, we investigated patterns of care for liver SBRT and factors influencing local control (LC) and overall survival (OS). Patients treated with SBRT were prospectively registered within a quality assurance project. Patient- and tumour-related factors, and data on use of markers, personalised immobilisation, image guidance and radiotherapy techniques were collected. OS and LC were evaluated by Kaplan-Meier analysis and Cox proportional hazard models. From August 2013 to December 2019, fourteen centres treated 352 patients with SBRT for a total of 408 lesions (66 primary, 342 metastases). Colorectal adenocarcinoma was the most common primary cancer (n = 170, 42%). A gradual uptake of SBRT and increasing prescription dose were observed over time. One, 2- and 5- year OS probabilities were 74.3%, 49.7% and 19.4%. LC data were available for 354 lesions. LC probabilities at 1-, 2- and 5-years were 69.9%, 52.2% and 32.4%. Better OS and LC were found for patients with smaller PTV volumes and higher BED10. Patients with better performance status had a better OS. A better LC was observed in patients who were not priorly treated with systemic therapy. We observed an increase in liver SBRT uptake and a reasonable LC and OS. Higher BED10 and smaller PTV volumes translated into high local tumour control and survival. After correction of patient case-mix, none of the technical parameters showed a significant association with outcome. Not applicable, this is a retrospective analysis of data that were prospectively registered as part of a national quality assurance programme of the Belgian Cancer Registry.