"We are doing a full kitchen remodel ourselves and I can't find a requirement for anchoring the romex cable in the wall behind the cabinet. "

Look in the the electric code.

Cables require fastening within a short distance of where they exit a junction box, unless the wires are fished into an existing cavity from access points (you do not need to cut a huge hole to allow fastening the cable inside the wall).

Cables run through bored holes are considered supported.

There are specific lengths given for how often a cable must be supported (and this can be accomplished by fastening them to the sides of joists and studs).

Thanks for the help. According the the documents provided by our town, wires must be fastened within 12 inches of the box or fixture. I wasn't sure how to interpret the wording. We will certainly fasten the romex to the cabinet at the point at which it comes through the drywall. So if the wire is stapled to the stud within 12 inches of where it is fastenedto the cabinet that should be OK. I will confirm with the inspector when he comes but I wanted to try to get it right.

Thanks

The 12 inches is for each box or fixture and that is all.

Other rules apply after that (and the spacing is much larger).