A 42-year-old man with a 15-year history of ulcerative colitis presents with progressive pruritus, jaundice, and fatigue. Liver function tests show elevated alkaline phosphatase (ALP 280 U/L) and gamma-glutamyl transferase (GGT 320 U/L) with mild hyperbilirubinemia. MRCP reveals the characteristic finding marked as **C** in the diagram — multiple strictures of intra- and extrahepatic bile ducts with intervening dilatations creating a "beaded" or "string of beads" appearance. Which of the following statements best reflects the clinical significance of this finding in the context of his ulcerative colitis?