Oligometastatic disease: where a patient has a limited burden of metastases and may benefit from metastasis-directed locally ablative treatments.

Synchronous oligometastatic disease: where oligometastatic disease presents at the time of initial diagnosis.

Metachronous oligometastatic disease: where oligometastatic recurrence presents at least 3 months after treatment of the initial primary site.

Oligorecurrence: a term used interchangeably with metachronous oligometastatic disease.

Oligoprogression: where a few lesions progressing on a background of widespread but stable disease.

Oligopersistence: persistent metastatic disease after systemic treatment.

Stereotactic ablative radiotherapy (SABR): highly focused radiation treatment that gives an intense dose of radiation concentrated on a site of cancer while limiting dose to surrounding organs.

Radiofrequency ablation: a treatment that uses heat made by radio waves to kill cancer cells.