pagefile.sys is not a cache for anything stored on the disk, it just stores data paged out of system RAM. It's virtual memory. Of course that doesn't mean it's any less likely to contain unencrypted data that was worked with at any point in time.
The only 100% reliable solution against leaving any unencrypted remnants behind is to encrypt the Windows system partition itself, including the pagefile.sys stored within it as well as any and all cache and temporary files created or modified during a Windows session.
(However, it depends on what's on those Truecrypt-encrypted volumes and how the OP is working with their contents in the first place.)
Another effective, though uncommon, method is to use software to automatically create and format a fixed-size RAM disk at boot time and allocate it with a pagefile.sys, enabling you to keep the pagefile out of any disk-based volumes without having to disable it altogether. Of course using a RAM disk to store a file that's used as virtual memory is a bit...backward
(I do this on my laptop though, since it has a full 1GB of RAM that my 32-bit Windows can't see but my RAM disk software is able to use separately.)
Clearing the pagefile.sys file at every Windows shutdown is an obvious and simple method requiring a single registry key change which is pretty trivial, but it'll delay the shutdown a lot, and this doesn't address the remaining issue of various cache and temp files left behind on the system volume.
For the record: Clear the page file at shutdown