ESTRO 2024 - Abstract Book

S2231

Clinical - Upper GI

ESTRO 2024

1 Seoul National University College of Medicine, Radiation Oncology, Seoul, Korea, Republic of. 2 Ewha Womans University College of Medicine, Radiation Oncology, Seoul, Korea, Republic of. 3 Seoul National University College of Medicine, Surgery, Seoul, Korea, Republic of. 4 Seoul National University College of Medicine, Internal Medicine, Seoul, Korea, Republic of. 5 Seoul National University College of Medicine, Pathology, Seoul, Korea, Republic of

Purpose/Objective:

The role and indication of adjuvant therapy in perihilar cholangiocarcinoma remain controversial. This study aims to evaluate the effect of adjuvant therapy and predict the prognosis of perihilar cholangiocarcinoma using a nomogram.

Material/Methods:

We retrospectively reviewed 176 perihilar cholangiocarcinoma patients who underwent curative resection between January 2000 and December 2022. We assessed clinicopathological and treatment factors associated with overall survival (OS), disease-free survival (DFS), locoregional recurrence-free survival (LRRFS), and distant metastasis-free survival (DMFS) using the Kaplan-Meier method. Resection margin status was classified as clear, close and involved for both longitudinal and circumferential margins.

Results:

The median follow-up period was 26.1 months (range: 0.7 - 264.8 months). Among all patients, 62.5% (n = 110) received adjuvant concurrent chemoradiotherapy (CCRT), while the remainder received adjuvant radiotherapy/chemotherapy alone (n = 18) or no adjuvant therapy (n = 48). Preoperative bile duct drainage significantly improved ALBI (Albumin-Bilirubin) grade (p < 0.001). The clearance cut-off value for resection margin was 0.09 cm for both longitudinal and circumferential margins. In 40.3% of cases (n = 71), the resection margin was involved with invasive cancer. Among the uninvolved 105 resection margins, 27.8% (n = 49) were close and 31.8% (n = 56) were clear. Nodal involvement was identified in 28.4% (n = 50). The 3-year OS, DFS, LRRFS, and DMFS were 44.1%, 38.2%, 43.5%, and 65.6%, respectively. Radiotherapy improved LRRFS in a subgroup of patients with at least one risk factor, which included advanced T stage, nodal involvement and close/involved resection margin (p = 0.025). Multivariate analysis revealed that a high ALBI grade (HR, 1.93; 95% CI 1.11-3.33; p = 0.019) and close/involved resection margin (HR, 1.90; 95% CI 1.10-3.29; p = 0.021) were poor prognostic factors, while a higher radiotherapy dose over 50 Gy EQD2 (HR, 0.54; 95% CI 0.30-0.96; p = 0.035) and adjuvant CCRT (HR, 0.38; 95% CI 0.15-0.93; p = 0.034) were associated with better OS. We propose a nomogram to predict prognosis based on the identified risk factors from the multivariate analysis.

Conclusion:

Adjuvant radiotherapy improved locoregional recurrence in high risk patients. This study developed a nomogram model to predict the prognosis of perihilar cholangiocarcinoma patients, incorporating prognostic factors for OS, including ALBI grade, resection margin status, radiotherapy dose exceeding 50 Gy EQD2 , and adjuvant CCRT.