Recurrence of Synovial Sarcomas

I lost my lower left leg and foot to synovial sarcoma then had four more recurrences in the first of seven years. It's been 13 years, six since I went through treatment for the fifth time. I was told it is when not if it will return and I'm being watched to make sure my lungs are clear and my liver is clear. My rad doc said that's the two places it could come back and show up. I wonder how many others have been through it several times and have been clear for several years now.