I have had my second recurrence of GCT, and am also a physical therapist. Are you getting inhibin A and B blood tests monthly, and CAT scans periodically to track potential growth? It is always good to be mindful of possible reoccurrence, and to consider that the number of surgeries you have had to the abdominal wall do weaken the muscles that support the spine. I have had this myself and see this often with clients, and so from personal experience and training, work with them to strengthen the core muscles with lumbar stabilization/simple pilates exercises. Doing both (tracking and strengthening) will be helpful.