First of all, I am sorry you are dealing with this cancer. It is so confounding and no one really knows what works and what does not.
I was dx in 1994 and I did have chemo. I was stage 1C, but the mitosis was high and the tumor was large which is why my doctors decided on the chemo. I had 3 rounds, 1 week on and then 2 weeks off. I was given a combo of BEP, cisplatin and something else which escapes me right now.
I am going on 15 years without a recurrance. I have no idea if the chemo helped or not. Perhaps I would not have recurred without the chemo. That is exactly the dilemma. No one really knows that much about this cancer. That being said, I am always waiting for the shoe to drop. I know this cancer can come back at any time. Very scary.
I know I have not been very much help at all. Best of luck with your decision. Please keep us posted on your progress. The one thing I have learned throughout this journey is that we with this weird cancer learn more from each other than we do from doctors. You may also want to go to www.ovca.net . They have complete threads on GCT and there is a lot of information there.