2.3. Follow-up

In the first year 3/4-monthly, in the 2nd and 3rd year 6-monthly, and in the 4th and 5th year 12 monthly after local treatment ¹⁸F-FDG-PET-CT with diagnostic ceCTs of the chest and abdomen were performed, according to national guidelines [31]. A ceMRI with diffusion-weighted images was used as problem solver. A ceCT-scan was performed within one to six weeks after the repeat local treatment, in the context of a presumably incomplete local treatment procedure. LTP was defined as an unequivocally and solid enlarging mass or focal ¹⁸F-FDG PET avidity at the surface of the ablated tumor for thermally ablated tumors or histopathological confirmation in case of uncertainty.