Need Information to appeal Insurance Company HIPEC decision

My cousin was diagnosed with Stomach cancer on 8/19.  He has begun his third round of systemic Chemo.  His oncologist has recommended the HIPEC procedure.  Unfortunately, Aetna has denied the procedure claiming it is experimental.  We are in the process of appealing this decision.  He is scheduled for stomach resection/ the HIPEC procedure mid November.  We are desparately looking for the following information:

1.       Anyone who had denials of: predetermination, precertification, preauthorization or appeals

2.   How the denials were overturned

3.  Who was the carrier?  If Aetna a contact name

4. Facility the performed Surgery/HIPEC

5.  Dr the performed surgery 

There are a few people who got this surgery done under the "Colon" message board.  You might want to post this message there.