Enhancement Patterns of Metastatic Intrahepatic Cholangiocarcinoma and Outcomes after Chemotherapy and Radiation

PURPOSE/OBJECTIVE(S)

Patients with metastatic intrahepatic cholangiocarcinoma (M1-iCCA) have a poor prognosis with a 5-year survival rate of less than 20%. Definitive doses of radiation therapy (RT) after upfront chemotherapy (chemo/RT) in this patient population have shown to prolong survival by reducing the risk of tumor-related liver failure compared to chemotherapy alone. Our group has also identified a baseline radiographic feature, the arterial enhancement pattern, which has pathological and prognostic associations for iCCA. We tested the hypothesis that baseline arterial enhancement is independently associated with survival outcomes for patients who receive chemo/RT or chemo alone.

MATERIALS/METHODS

Patients with M1-iCCA from 2010 to 2021 were included in this retrospective study. Patients were grouped into those who underwent chemo alone and those who underwent chemo/RT. The inclusion criteria included confirmed diagnosis of M1-iCCA, availability of baseline multi-phasic computed tomography (CT), and follow-up for at least six months or until death. Tumor arterial enhancement patterns were categorized as previously described into hypovascular or hypervascular, where the tumors that were hypervascular had either peripheral enhancement or central enhancement. Mean tumor density in Hounsfield units was recorded for each patient. Survival was estimated using the Kaplan Meier method, and Cox proportional models were used to adjust for prognostic variables.

RESULTS

A total of 281 patients with iCCA were identified and 229 had evaluable CT scans. Demographic and baseline characteristics of patient groups are shown in the Table. On univariate analysis, patient age, ECOG performance status (PS) at diagnosis, treatment type, and arterial enhancement patterns associated with overall survival (OS). On multivariable analysis, the arterial enhancement pattern independently associated with OS after accounting for covariates. Patients with hypervascular tumors had prolonged OS compared to those with hypovascular tumors (HR = 0.72, [0.54 - 0.96], p = 0.02). Prolonged OS was also observed in the chemo/RT group compared to the chemo alone group (HR = 0.37, [0.25-0.54], p< 0.0001).

CONCLUSION

Baseline enhancement patterns of M1-iCCA were prognostic in the contexts of chemo alone and chemo/RT. This imaging-based biomarker may improve the ability to stratify patients for therapeutic management.

Definitive Liver Radiotherapy for Intrahepatic Cholangiocarcinoma with Extrahepatic Metastases

Introduction

Tumor-related liver failure (TRLF) is the most common cause of death in patients with intrahepatic cholangiocarcinoma (ICC). Though we previously showed that liver radiotherapy (L-RT) for locally advanced ICC is associated with less frequent TRLF and longer overall survival (OS), the role of L-RT for patients with extrahepatic metastatic disease (M1) remains undefined. We sought to compare outcomes for M1 ICC patients treated with and without L-RT.

Methods

We reviewed ICC patients that found to have M1 disease at initial diagnosis at a single institution between 2010 and 2021 who received L-RT, matching them with an institutional cohort by propensity score and a National Cancer Database (NCDB) cohort by frequency technique. The median biologically effective dose was 97.5 Gy (interquartile range 80.5-97.9 Gy) for L-RT. Patients treated with other local therapies or supportive care alone were excluded. We analyzed survival with Cox proportional hazard modeling.

Results

We identified 61 patients who received L-RT and 220 who received chemotherapy alone. At median follow-up of 11 months after diagnosis, median OS was 9 months (95% confidence interval [CI] 8-11) and 21 months (CI: 17-26) for patients receiving chemotherapy alone and L-RT, respectively. TRLF was the cause of death more often in the patients who received chemotherapy alone compared to those who received L-RT (82% vs. 47%; p = 0.001). On multivariable propensity score-matched analysis, associations with lower risk of death included duration of upfront chemotherapy (hazard ratio [HR] 0.82; p = 0.005) and receipt of L-RT (HR: 0.40; p = 0.002). The median OS from diagnosis for NCDB chemotherapy alone cohort was shorter than that of the institutional L-RT cohort (9 vs. 22 months; p < 0.001).

Conclusion

For M1 ICC, L-RT associated with a lower rate of death due to TRLF and longer OS versus those treated with chemotherapy alone. Prospective studies of L-RT in this setting are warranted.