The oligometastatic paradigm and the role of radiotherapy

Abstract

Most cancer-related deaths are due to metastatic disease. There is now an emerging evidence base suggesting that a subgroup of metastatic patients benefit significantly from local resection (surgery) or ablation (stereotactic ablative body radiation, SABR) of their metastatic sites. These patients are in what has been termed the 'oligometastatic state', a transitional window between local and disseminated disease where locally ablative, metastasis-directed therapy prolongs progression-free survival, improves overall survival and sometimes achieves cure. Appropriately selecting those who fit this oligometastatic phenotype, while integrating advances in ablative technologies such as SABR with modern systemic treatments, is an evolving challenge for oncologists.

Keywords: RFA; SABR; metastasectomy; oligometastatic; oligoprogression.

Fig 1

Kaplan-Meier plots for a) overall survival and b) progression-free survival seen in the SABR COMET Trial.

Fig 2

Case example oligometastatic SABR. (a) A 53-year-old woman with a background history of triple-negative local breast cancer presents, 2 years after her initial diagnosis, with a solitary biopsy-proven liver metastasis (arrow). (b) She undergoes 45 Gy in 3 fractions SABR to this oligometastatic site. (c) A 6-month post treatment MRI shows a complete response to treatment (arrow).