Stereotactic Ablative Radiotherapy to Treat Colorectal Liver Metastases: Ready for Prime-Time?

Background: Stereotactic Ablative Radiotherapy (SABR) is a non-invasive treatment option for patients with Colorectal Liver Metastases (CRLM) ineligible for resection or thermal ablation. The aim of our study was to evaluate local control, disease progression, toxicity, complications and survival after SABR of CRLM. We also discuss the place of SABR in the treatment algorithm of CRLM. Methods: Patients with CRLM, ineligible for resection or thermal ablation and suitable for SABR, were included in our database and retrospectively analyzed. Patients with oligometastases <5 cm without the presence of other organs in the target area are eligible for SABR. Follow-up imaging was conducted at 3 and 6 months following SABR and 6-monthly thereafter. Total delivered dose per lesion was 54-60 Gy, divided over 3-12 fractions, depending on the dose constraints of normal tissues. Results: Ten patients with 13 lesions were treated with SABR. Complete local control was achieved in eight patients with 11 lesions, with a median follow-up of 20.4 months (range 7-38). Two patients showed possible local progressive disease after 12 and 25 months. No toxicity > grade 2 as a result of treatment was reported. Eight patients had died at time of analysis; median survival was 26 months. Conclusion: SABR of CRLM is safe, feasible and effective in achieving local control in patients ineligible for resection or thermal ablation. Although SABR is currently offered in a late and often palliative stage, it deserves a higher profile as a possible local treatment option and its place in the treatment algorithm should be re-evaluated.