Monthly NCIt Retires & Merges

Occasionally, concepts are retired or merged. This can happen due to a variety of reasons, but mainly it is because scientific literature supports the change or a duplicate concept was discovered.

NCIt_RetiresMerges files are available for download from the NCI EVS ftp site ( The file is appended with the version of the Thesaurus which is in the format of Year.Month.Monday, i.e., 21.08e is 2021 - August, and the 5th Monday (i.e., "e") of the month.


The database is reconciled the last Monday of every month; this is the database from which a production version is generated to correspond to the files posted on the ftp site. The files will be posted during the following two weeks.

Previous versions of the RetiresMerges files can be found on the following website (

Help requests on these files should go to