10. Each progression metastases fulfills at least 1 of the 3 following criteria for oligo-progression: a. Progression of an individual metastasis according to RECIST 1.1 criteria (≥ 20% enlargement of the tumour vs. baseline or nadir, taking as reference the smallest diameter seen prior to starting or during first line systemic therapy and associated with a 5 mm minimum increase in size); b. Unambiguous development of a new metastatic lesion from the time of scan taken prior to starting first-line therapy with sunitinib; c. Progressive enlargement of a known metastasis on 2 consecutive imaging studies 2-3 months apart, while receiving first-line therapy with sunitinib, with a minimum 5 mm increase in size from baseline.