Cancer Survivors Network

I have a question that I hope someone can give me some info about.
My husband has prostat cancer and has spread to the bones. He is on zometa, caodex and lupron. In the last month he is having fever almost everyday. from 99-102(mostly 100.2) the dr. at mskcc have taken blood, urin, chest xray and cultures. Every thing came back neg. they cannot find anything wrong. If anyone else has had a similar experence or has a answer I would appreciate it. They are thinking of starting him on chem next because his psa is slowly on the rise. but his other signs are fine. We are going to mskcc on 4/12 hopefully they can give some answers too. He is also only 58.
Thank You and G-d bless