Anatomic-Biologic Borderline Resectability Criteria Improve Recurrence Risk Stratification in Perihilar...

Area of Science:

• Hepatobiliary surgery
• Surgical oncology
• Gastroenterology

Background:

• Borderline resectability in perihilar cholangiocarcinoma (pCCA) is typically defined anatomically.
• Anatomical definitions may not fully capture the oncologic risk associated with pCCA.
• This study investigates if biologic markers improve recurrence stratification after curative-intent resection.

Purpose of the Study:

• To evaluate the utility of biologic burden, specifically carbohydrate antigen (CA19-9) levels, in refining recurrence risk stratification for pCCA.
• To compare the prognostic performance of anatomical definitions versus an integrated anatomic-biologic approach.

Main Methods:

• Utilized an international, multi-institutional database of patients with non-metastatic pCCA undergoing resection without neoadjuvant therapy.
• Defined literature-based borderline resectability (BR) based on lymph node metastasis, vascular involvement, or Bismuth type IV disease.
• Developed a three-tier anatomic-biologic borderline resectable (AB-BR) grouping using a 200-U/mL CA19-9 cutoff to assess recurrence-free survival (RFS).

Main Results:

• Anatomical BR alone did not significantly stratify RFS or overall survival (OS).
• CA19-9 levels ≥200 U/mL stratified RFS within both resectable and BR groups (p < 0.05).
• The AB-BR framework demonstrated improved RFS prediction (AUC 0.612 vs. 0.537) and identified an intermediate-risk group, with 2-year RFS rates of 55.7% (low), 37.8% (intermediate), and 25.3% (high) (p = 0.002).

Conclusions:

• Anatomical borderline resectability offers limited prognostic value for pCCA recurrence.
• Incorporating CA19-9 levels into an anatomic-biologic framework significantly enhances prediction of recurrence after pCCA resection.
• The AB-BR model supports oncologically informed surgical decision-making beyond purely technical resectability.