Tumor necrosis impacts prognosis of patients undergoing resection for T1 intrahepatic cholangiocarcinoma: implications for modification of 8th AJCC T classification

Abstract

Presenter: Diamantis Tsilimigras MD | The Ohio State University Background: Tumor necrosis has been associated with unfavorable prognosis among patients with hepatocellular carcinoma and hilar cholangiocarcinoma. The prognostic impact of tumor necrosis among patients undergoing resection for intrahepatic cholangiocarcinoma (ICC) remains ill-defined. Methods: Patients who underwent curative-intent resection for ICC between 2000-2017 were identified using an international multi-institutional database. The association of tumor necrosis (absent, moderate [50%]) with clinicopathologic characteristics and the impact on overall (OS) and recurrence-free survival (RFS) were examined. Results: Among 757 patients who underwent resection for ICC, tumor necrosis was present in 384 (50.7%) patients (no necrosis: n=373, 49.3%, < 50% necrosis: n=291, 38.4%, > 50% necrosis: n=93, 12.3%). Tumor necrosis was associated with unfavorable clinicopathologic characteristics, including tumor size > 5 cm (necrosis vs no necrosis; 67.4% vs 57.6%), CA19-9 > 200 ng/mL (35.5% vs 26.0%), liver capsule involvement (43.7% vs 19.8%) and poor/undifferentiated tumor grade (32.8% vs 21.8%) (all p<0.05). Tumor necrosis was associated with worse OS (5-year OS; no necrosis: 39.3% vs < 50% necrosis: 34.7% and > 50% necrosis: 24.0%, p=0.03) and RFS (5-year RFS: no necrosis: 25.7% vs < 50% necrosis: 13.9% and > 50% necrosis: 18.8%, p<0.001). After stratifying by T stage, tumor necrosis was able to further stratify prognosis among patients with T1a ICC (5-year RFS; T1a & no necrosis: 46.7% vs T1a & necrosis: 36.1%, p=0.02), and T1b ICC (5-year RFS; T1b & no necrosis: 31.1% vs T1b & necrosis: 11.2%, p=0.006), but was not associated with outcomes among patients with more advanced T2-T4 disease. Patients with T1a ICC & tumor necrosis had similar RFS as individuals with T1b ICC and no tumor necrosis (5-year RFS; T1a & necrosis: 36.1% vs T1b & no necrosis: 31.1%, p=0.66) (Figure) Conclusion: Tumor necrosis was associated with worse prognosis among patients with T1 ICC. A modified AJCC T classification that incorporates tumor necrosis for T1 ICC should be considered to further stratify outcomes of patients with early T-stage ICC.