<prompt> Which of the following is the Post - Chemotherapy based staging system in Wilms tumor:National Wilms Tumor staging System NWTSGNational Wilms Tumor staging System NWTSGAJCC TNMChadwick  <response>: Answer is B International Society of Pediatric Oncology-STOP : The post-chemotherapy based staging system is the SLOP staging system developed by the International society of pediatric oncology. 