- Patients must have radiographically or biochemically measurable disease; radiographically measurable disease is defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded) as >= 20 mm with conventional techniques or as >= 10 mm with spiral computed tomography (CT) scan; biochemically measurable disease is defined as an elevated thyroglobulin (WDTC patients) or calcitonin (MTC patients)