3.2 Observable Entity/Observation Pairs versus Clinical Findings

Historical SNOMED CT content authored for use in cancer synoptic reporting can be found in the Observable entity and Clinical finding hierarchies.   

Observable Entities vs Clinical Findings

The vast majority of these concepts are primitive and have effective dates of 2001-01-31, which is the beginning of SNOMED CT time.  These concepts were deemed insufficient to unambiguously represent pathology observations and findings for use in cancer registries.  An early design decision in the Cancer Synoptic Reporting Project Group project was to use the Observable entity hierarchy instead of the Clinical finding hierarchy.  Regardless of approach, substantial concept modeling would be required in either hierarchy.  Ultimately, the decision was made to provide a tangible, needed, and practical use case upon which to demonstrate the efficacy of the newly remodeled Observable entity concept model.  Apart from the novelty of the approach, the question, or Observable entity, in each synoptic report must carry sufficient context to unambiguously interpret the observation or finding. 

A practical consideration for this modelling approach pertained to the amount of new content that would be necessary to create to meet the needs of the cancer synoptic use case.

Content Development Approach

A significant number of concepts have been created as part of this effort, encompassing all hierarchies. In retrospect, the decision to utilize observable entities to encompass the complete clinical context for each observable entity/observation pair proved beneficial in managing the concept volume effectively.

The histologic type of "malignant neoplasm of organ X" is a good example of this.

Every organ system with a reporting protocol has an average of 10-20 morphologic abnormalities that could be recorded.  Many of these morphologies may be observed in multiple organ systems. If clinical findings were used to represent the protocol data, a new concept would be necessary for every organ/morphology pair for example:

• adenocarcinoma of organ X
• mucinous adenocarcinoma of organ X
• serrated carcinoma of organ X

Using observable entities, however, required only a single concept to be created for each organ system  The observable entity (e.g., Histologic type of malignant neoplasm of organ X) could be paired with any number of valid morphologies. Ultimately, the decision required less new content to be developed and maintained.

It should be noted that the observable entity/observation pairs in the Cancer Synoptic Reporting Project Group product do NOT follow the clinical finding MRCM specific that uses the defining attributes  363714003 |Interprets (attribute)|  = <<  363787002 |Observable entity (observable entity)|  AND  363713009 |Has interpretation (attribute)|  = <<  260245000 |Finding value (qualifier value)| .  The types of information solicited in the cancer pathology protocols extend beyond the content represented in the Qualifier value hierarchy and include values from the Procedure hierarchy, Body structure hierarchy, and concepts in the qualifier hierarchy NOT subsumed by <<  260245000 |Finding value (qualifier value)|   and discrete numerical values.  Current MRCM rules for clinical findings do not include these concept areas in the range of possible concepts for  |Has interpretation (attribute)| . Pathology synoptic data elements simply record a series of individual observations in a structured fashion.