If you need to use NaOH specifically, this in itself is not an efficient cleaner and it will be better if combined with a surfactant. One of the best on the market is from a company called STERIS and is called ProKlenz ONE.
Obviously the validation requirments will change slightly, but the surfactant in this product is HPLC detectable and will make the validation of its removal easier to monitor. in this case, TOC can also be used to assess the removal of both cleaning agent (which can’t be done if only NaOH is used) and process residue. Obviously if you get a TOC signal that is above the threshold, you will then need to identify where it comes from, but basically, TOC from cleaning agent means your rinsing process is incomplete. If, however, the TOC comes from the process residues, your cleaning process needs to be optimised.