My daughter’s tumor was grade 2 on her ankle. The main issue is that the Dr. told me not to do anything for a few years. That it was nothing to worry about. I listened and then it was too late. It spread to her lungs.
Right now she is in no treatment. We discovered this in July 2017 and had radiation in August 2017 followed by a second surgery in October 2017. The tumor on the lungs are too small for any type of radiation or surgery and Chemo was not recommended yet.
As I told you. it looks like you caught the monster on time and your son should be fine. Just monitor the lungs on a regular basis with a CT scan. Sometimes the scans show clear for a year or two before the tumors show up. If you get clear scans for 5 years then your son will have a long and healthy life.