XLR to RCA any bad in long runs?

Hi, I have a long run of XLR cable (about 40ft)between my HT proccesor and power amps(they are in different rooms). Now, I want to use a preamp close to my power amps so still have to use my long run of cable BUT because this preamp only has RCa's I need to use an adaptor at the end of the cables. My question: because I've always heard that is much better to use XLR cable in long runs to avoid noise, is neccesary to go XLR end to end or can I use an RCA adaptor at the end of the line with no adverse effects? Thanks in advance.