Sorafenib Completed Phase 2 Trials for Thyroid Papillary Carcinoma / Recurrent Childhood Liver Cancer / Childhood Hepatocellular Carcinoma / Previously Treated Childhood Rhabdomyosarcoma / Recurrent Childhood Rhabdomyosarcoma / Recurrent Thyroid Cancer / Recurrent Wilms Tumor and Other Childhood Kidney Tumors Treatment