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Q. How are NCI Thesaurus concepts related to UMLS Concept Unique Identifiers (CUIs)?

The NCI Thesaurus is one of the vocabulary sources included in the NCI Metathesaurus, a vocabulary resource that maps terms from multiple sources to unique concepts identified by a Concept Unique Identifier, or CUI. The NCI Metathesaurus is partially based on the UMLS Metathesaurus; CUIs in the NCI Metathesaurus originate predominantly from assignments made in the UMLS. When NCI Thesaurus concepts are mapped (or merged) to UMLS concepts in the NCI Metathesaurus, they become associated with the CUI of the parent UMLS concepts. If an NCI Thesaurus concept doesn't have an equivalent UMLS concept to merge to, a CUI is still assigned to it; however, this CUI is specific to the NCI
Metathesaurus. In the NCI Metathesaurus, the CUI identifies each concept; in the standalone NCI Thesaurus, the concept code is the actual identifier.

Q. What is the difference between the NCI Thesaurus and the Metathesaurus?

The NCI Thesaurus is the NCICB preferred terminology for creating metadata (e.g. data elements) in the caDSR.

About the NCI Thesaurus: The NCI Thesaurus is a biomedical thesaurus created specifically to meet NCI's need for a well-designed ontology that covers cancer science. The Thesaurus was ranked as one of the two best biomedical terminologies in the country by the National Center for Vital Health Statistics and has been nominated as a standard by the Consolidated Health Informatics initiative (the health related component of eGOV). The Thesaurus is updated monthly and is a self-contained and logically consistent terminology. This means that terms have rich, complete descriptions and have been placed into an ontology of other NCI terms. This makes the NCI Thesaurus a good source on which to base the NCICB's metadata curation and UML model transformation activities.

Using the NCI Thesaurus: If you are going to transform a UML Model into caDSR metadata, you need to map the classes and attributes to NCI Thesaurus concepts (terms). Using the SIW (Semantic Integration Workbench) tool, search the Thesaurus to find the best possible mapping for what you are trying to describe.

About the NCI Metathesaurus: The NCI Metathesaurus is based on the UMLS Metathesaurus, supplemented with additional cancer-centric vocabularies developed at the NCI. Basic information is added about each concept and new associations are made to help establish synonymy and other relationships among concepts from different sources. As more of a mapping of terms across terminologies, the NCI Metathesaurus is not the preferred choice for giving you a consistent single term when curating metadata.

Using the NCI Metathesaurus: If you are attempting to curate a new CDE based on a set of permissible values and you do not know the exact source of the values for that question, you could use the NCI Metathesaurus and leverage the mapping between the different terminologies to determine if the permissible values were based in some part on a standard (i.e. LOINC). As a curator, you may then want to make the decision to standardize those permissible values to that terminology based on that match.