Fibrosarcoma-looking for doctor/facility recommendations

Hello,

I have a sister who has had fibrosarcoma recur 4 times. She has underwent 3 surgeries (knee, ribs and lung) and will have a forth coming up (near ribs again). She has also been treated with chemotherapy. Her doctor has been responsibly consulting with other sarcoma specialists nationwide, but I would like to know if anyone has any recommendations for a second opinion. It has been difficult to research "who" has the most experience with this type of cancer and I was hoping to get some feedback. Thank you fo rany info!