sarcoma again appear

my sister is 15 year old and when she was 10 year old sarcoma(soft tissue)diagnose on right leg below knee. we admitted him hospital where doctors treated ( surgery, chemo and radiation process). but after one year sarcoma at leg on other position again diagnose now doctors again go through same process we are so sad and going to painful situation. we are belong to poor family and can't afford costly treatment. please help us