This page is part of the MII IG Kerndatensatz-Modul Onkologie (v2027.0.0-ballot.1: Release) based on FHIR (HL7® FHIR® Standard) R4. This is the current published version in its permanent home (it will always be available at this URL). For a full list of available versions, see the Directory of published versions

Extensions

The complete, automatically generated list of this module's extensions can be found in the artifact overview. This page documents the design decisions: why extensions were needed and which alternatives were discussed.

Use of extensions

The oBDS implementation uses extensions. This is mainly due to the oBDS data structure, the oBDS-specific code systems and the attempt to represent them with modules of the MII core dataset. The extensions were designed with a focus on integration into the MII core dataset and the secondary use of cancer registry data via the FDPG.

Since the use of extensions should be avoided in FHIR where sensible alternatives exist within the existing FHIR data model, implementation alternatives are shown and discussed below.

Procedure extensions (intention, timing relative to surgery)

Intention

• Why the extension is needed:
  • The FHIR R4 Procedure has no element that can adequately represent the treatment intention.
  • The MII Procedure therefore contains an extension Durchführungsabsicht.
  • CarePlan does have the intent element; however, it describes the bindingness of the resource (plan, option, order etc.) and cannot be used to code the treatment intention in the oBDS sense.
• Alternative proposal: a consented SNOMED mapping might allow the treatment intention to be captured directly in SNOMED CT and transported via the Durchführungsabsicht extension.

Timing relative to surgical therapy (Stellung)

The timing of a radiotherapy or systemic therapy relative to surgery cannot be represented with the existing FHIR procedures. Representation via another resource (e.g. in CarePlan as part of the tumor conference) was discussed but not considered advantageous.

Radiotherapy irradiation extension

• Why the extension is needed: representing the complex oBDS irradiation type with traditional FHIR resources is currently only partially possible.
• Individual irradiations cannot be represented as separate MII procedures, as mandatory OPS or SNOMED CT codes would be required that do not exist for all oBDS data fields.
• Alternative proposal:
  • keep radiotherapy as an MII procedure,
  • define the irradiation as an R4 procedure:
    • bodySite for the target volume, with laterality extension,
    • code as application type,
    • method as a slice for the radiation type,
    • dose and boost still represented via extensions.

TNM extensions (c/p prefix, itc, sn)

Alternative implementations:

• as individual observations with the existing TNM grouper logic
  • advantage: behaves exactly like other categories and symbols
  • disadvantage: does not occur independently; tight coupling to the T/N/M classification profiles required
• as part of the T/N/M categories (e.g. component)

Irradiation extensions (single irradiation)

The radiation extensions capture all information relevant to individual radiation units that is not already covered by the parent Strahlentherapie procedure profile.

Total dose

The total dose indicates the total dose with which the target region was irradiated (including boost).

Structure and description: MII EX Onko Strahlentherapie Bestrahlung Gesamtdosis.

Single fraction dose

The single fraction dose indicates the dose (most frequent dose, not boost) per day with which the target region was irradiated.

Structure and description: MII EX Onko Strahlentherapie Bestrahlung Einzeldosis.

Boost

Indicates whether a boost was applied and, if so, which type of boost.

Structure and description: MII EX Onko Strahlentherapie Bestrahlung Boost.

Laterality

Indicates the laterality of the target region. For bilateral irradiation of paired organs, the irradiations are to be reported individually.

Structure and description: MII EX Onko Strahlentherapie Bestrahlung Seitenlokalisation.

Note: the former complex parent extension mii-ex-onko-strahlentherapie-bestrahlung has been superseded (commented out in FSH); the four individual extensions on the irradiation procedure profile apply.