Planning Trade-offs for SABR in Patients With 4 to 10 Metastases: A Substudy of the SABR-COMET-10 Randomized Trial

The oligometastatic state refers to a clinical scenario where a cancer is no longer localized, but not yet widely metastatic. Although many trials define the oligometastatic state as 1 to 3 or 1 to 5 metastatic lesions, there is no universally accepted definition. 1 Palma DA Olson R Harrow S et al. Stereotactic ablative radiotherapy versus standard of care palliative treatment in patients with oligometastatic cancers (SABR-COMET): A randomized, phase 2, open-label trial. Lancet. 2019; 393: 2051-2058 Abstract Full Text Full Text PDF PubMed Scopus (920) Google Scholar , 2 Gomez DR Blumenschein Jr., GR Lee JJ et al. Local consolidative therapy versus maintenance therapy or observation for patients with oligometastatic non-small-cell lung cancer without progression after first-line systemic therapy: A multicentre, randomised, controlled, phase 2 study. Lancet Oncol. 2016; 17: 1672-1682 Abstract Full Text Full Text PDF PubMed Scopus (665) Google Scholar , 3 Iyengar P Wardak Z Gerber DE et al. Consolidative radiotherapy for limited metastatic non-small-cell lung cancer: A phase 2 randomized clinical trial. JAMA Oncol. 2018; 4:e173501 Crossref Scopus (528) Google Scholar , 4 Ruers T Punt C Van Coevorden F et al. Radiofrequency ablation combined with systemic treatment versus systemic treatment alone in patients with non-resectable colorectal liver metastases: A randomized EORTC Intergroup phase II study (EORTC 40004). Ann Oncol. 2012; 23: 2619-2626 Abstract Full Text Full Text PDF PubMed Scopus (289) Google Scholar A recently published ESTRO-ASTRO consensus article, in defining oligometastasis, states that "the possibility to safely deliver curative intent metastasis-directed radiation therapy determines the maximum number." 5 Lievens Y Guckenberger M Gomez D et al. Defining oligometastatic disease from a radiation oncology perspective: An ESTRO-ASTRO consensus document. Radiother Oncol. 2020; 148: 157-166 Abstract Full Text Full Text PDF PubMed Scopus (175) Google Scholar However, the maximum number of metastases that can be safely treated is unknown.