Thermal Ablation versus Stereotactic Ablative Body Radiotherapy to Treat Unresectable Colorectal Liver Metastases: A Comparative Analysis from the Prospective Amsterdam CORE Registry

Sanne Nieuwenhuizen; Madelon Dijkstra; Robbert S Puijk; Florentine E F Timmer; Irene M Nota; Jip Opperman; Bente van den Bemd; Bart Geboers; Alette H Ruarus; Evelien A C Schouten; Jan J J de Vries; Hester J Scheffer; Anne M van Geel; Jan Hein T M van Waesberghe; Rutger-Jan Swijnenburg; Kathelijn S Versteeg; Birgit I Lissenberg-Witte; M Petrousjka van den Tol; Cornelis J A Haasbeek; Martijn R Meijerink

doi:10.3390/cancers13174303

Thermal Ablation versus Stereotactic Ablative Body Radiotherapy to Treat Unresectable Colorectal Liver Metastases: A Comparative Analysis from the Prospective Amsterdam CORE Registry

Cancers (Basel). 2021 Aug 26;13(17):4303. doi: 10.3390/cancers13174303.

Authors

Sanne Nieuwenhuizen¹, Madelon Dijkstra¹, Robbert S Puijk¹, Florentine E F Timmer¹, Irene M Nota¹, Jip Opperman², Bente van den Bemd¹, Bart Geboers¹, Alette H Ruarus¹, Evelien A C Schouten¹, Jan J J de Vries¹, Hester J Scheffer¹, Anne M van Geel², Jan Hein T M van Waesberghe¹, Rutger-Jan Swijnenburg³, Kathelijn S Versteeg⁴, Birgit I Lissenberg-Witte⁵, M Petrousjka van den Tol⁴, Cornelis J A Haasbeek⁶, Martijn R Meijerink¹

Affiliations

¹ Department of Radiology and Nuclear Medicine, Amsterdam UMC, Cancer Center Amsterdam, VU University, 1081 HV Amsterdam, The Netherlands.
² Department of Radiology and Nuclear Medicine, Noordwest Ziekenhuisgroep, 1815 JD Alkmaar, The Netherlands.
³ Department of Surgery, Amsterdam UMC, Cancer Center Amsterdam, VU University, 1081 HV Amsterdam, The Netherlands.
⁴ Department of Medical Oncology, Amsterdam UMC, Cancer Center Amsterdam, VU University, 1081 HV Amsterdam, The Netherlands.
⁵ Department of Epidemiology and Data Science, Amsterdam UMC, Cancer Center Amsterdam, VU University, 1081 HV Amsterdam, The Netherlands.
⁶ Department of Radiation Oncology, Amsterdam UMC, Cancer Center Amsterdam, VU University, 1081 HV Amsterdam, The Netherlands.

Abstract

Thermal ablation and stereotactic ablative radiotherapy (SABR) are techniques to eradicate colorectal liver metastases (CRLM). This study compares the safety, efficacy and long-term oncological outcomes of these treatment methods. All prospectively registered patients (AmCORE registry) treated with thermal ablation or SABR alone for unresectable CRLM between 2007 and 2020 were analyzed using multivariate Cox-proportional hazard regression. In total 199 patients were included for analysis: 144 (400 CRLM) thermal ablation; 55 (69 CRLM) SABR. SABR patients were characterized by older age (p = 0.006), extrahepatic disease at diagnosis (p = 0.004) and larger tumors (p < 0.001). Thermal ablation patients were more likely to have synchronous disease, higher clinical risk scores (p = 0.030) and higher numbers of CRLMs treated (p < 0.001). Mortality was zero and morbidity low in both groups: no serious adverse events were recorded following SABR (n = 0/55) and nine (n = 9/144 [6.3%]; all CTCAE grade 3) after thermal ablation. SABR was associated with an inferior overall survival (OS) (median OS 53.0 months vs. 27.4 months; HR = 1.29, 95% CI 1.12-1.49; p = 0.003), local tumor progression-free survival (LTPFS) per-tumor (HR = 1.24, 95% CI 1.01-1.52; p = 0.044) and local control per-patient (HR = 1.57, 95% CI 1.20-2.04; p = 0.001) and per-tumor (HR = 1.89, 95% CI 1.44-2.49; p < 0.001). In this study thermal ablation was superior to SABR with regard to OS, LTPFS and local control, albeit at the cost of a limited risk of serious adverse events. Further studies are required to assess whether the worse outcomes following SABR were the effect of true differences in ablative treatment or a result of residual confounding.

Keywords: colorectal liver metastases (CRLM); microwave ablation (MWA); radiofrequency ablation (RFA); stereotactic ablative radiotherapy (SABR); thermal ablation.