NPCR-internal code system representing the 5-point likelihood scale used by two MRI findings variables in NPCR Anmälan:

• D_EPE (Extraprostatic extension likelihood)
• D_SVI (Seminal vesicle invasion likelihood)

Both variables share the identical 5-point Listvärden pattern (from 'mycket sannolikt inte' to 'mycket sannolikt' plus 'Uppgift saknas'), differing only in the clinical finding being assessed. This shared CodeSystem enables a single reusable terminology artifact across both extensions, analogous to the NPCRBiopsyFlag pattern where multiple biopsy-related variables share 0/1/98.

The 5 likelihood levels reflect the standard radiology reporting convention for characterizing findings on prostate MRI:

• 1 = Mycket sannolikt inte (very unlikely)
• 2 = Sannolikt inte (unlikely)
• 3 = Risk (equivocal / at risk)
• 4 = Sannolikt (likely)
• 5 = Mycket sannolikt (very likely)
• 98 = Uppgift saknas (information missing)

Clinical note: Per NPCR Variabelbeskrivning Beteende/logik (effective 2025-05-20), these variables become synlig only when PI-RADS = 4 or 5 (i.e., EPE/SVI assessment is reported only for high-likelihood cancer cases). When PI-RADS = 3, EPE and SVI should not be reported per NPCR Manual guidance.

Terminology binding rationale: NPCR documentation does not provide an international code system binding for these likelihood scales. This CodeSystem preserves NPCR's internal coded values. Mapping to SNOMED CT concepts such as 371510008 (Extraprostatic extension of prostate cancer) and 399490008 (Seminal vesicle invasion) is noted as future work — those SNOMED CT concepts identify the finding but do not represent the likelihood gradation on a 5-point scale.