 - defined according to RECIST 1.1: at least one lesion, not irradiated, that can be accurately measured as 10 mm in the longest diameter except lymph nodes which must have short axis 15 mm with CT or MRI and which is suitable for accurate repeated measurements. Measurable lesions with calcifications should not be assessed as target lesions unless no other measurable lesion is available. 6. Known definite RET mutation status definition according to section 3.2. The status should be: 