Transarterial Radioembolization (TARE) Global Practice Patterns: An International Survey by the Cardiovascular and Interventional Radiology Society of Europe (CIRSE).

PURPOSE: An international survey was conducted by the Cardiovascular Interventional Radiological Society of Europe (CIRSE) to evaluate radioembolization practice and capture opinions on real-world clinical and technical aspects of this therapy. MATERIALS AND METHODS: A survey with 32 multiple choice questions was sent as an email to CIRSE members between November and December 2022. CIRSE group member and sister societies promoted the survey to their local members. The dataset was cleaned of duplicates and entries with missing data, and the resulting anonymized dataset was analysed. Data were presented using descriptive statistics. RESULTS: The survey was completed by 133 sites, from 30 countries, spanning 6 continents. Most responses were from European centres (87/133, 65%), followed by centres from the Americas (22/133, 17%). Responding sites had been performing radioembolization for 10 years on average and had completed a total of 20,140 procedures over the last 5 years. Hepatocellular carcinoma treatments constituted 56% of this total, colorectal liver metastasis 17% and cholangiocarcinoma 14%. New sites had opened every year for the past 20 years, indicating the high demand for this therapy. Results showed a trend towards individualized treatment, with 79% of responders reporting use of personalized dosimetry for treatment planning and 97% reporting routine assessment of microsphere distribution post-treatment. Interventional radiologists played an important role in referrals, being present in the referring multi-disciplinary team in 91% of responding centres. CONCLUSION: This survey provides insight into the current state of radioembolization practice globally. The results reveal the increasing significance placed on dosimetry, evolving interventional techniques and increased technology integration.

Iodine-125 seed inhibits proliferation and promotes apoptosis of cholangiocarcinoma cells by inducing the ROS/p53 axis.

With advances in radioactive particle implantation in clinical practice, Iodine-125 (125I) seed brachytherapy has emerged as a promising treatment for cholangiocarcinoma (CCA), showing good prognosis; however, the underlying molecular mechanism of the therapeutic effect of 125I seed is unclear. To study the effects of 125I seed on the proliferation and apoptosis of CCA cells. CCA cell lines, RBE and HCCC-9810, were treated with reactive oxygen species (ROS) scavenger acetylcysteine (NAC) or the p53 functional inhibitor, pifithrin-α hydrobromide (PFTα). Cell counting kit-8 (CCK-8) assay, 5-bromo-2-deoxy-uridine (BrdU) staining, and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay and flow cytometry assay were performed to test the radiation-sensitivity of 125I seed toward CCA cells at different radiation doses (0.4 mCi and 0.8 mCi). 2,7-dichlorofluorescein diacetate (DCF-DA) assay, real-time quantitative polymerase chain reaction (RT-qPCR), and western blot analysis were performed to assess the effect of 125I seed on the ROS/p53 axis. A dose-dependent inhibitory effect of 125I seeds on the proliferation of CCA cells was observed. The 125I seed promoted apoptosis of CCA cells and induced the activation of the ROS/p53 pathway in a dose-dependent manner. NAC or PFTα treatment effectively reversed the stimulatory effect of 125I seed on the proliferation of CCA cells. NAC or PFTα suppressed apoptosis and p53 protein expression induced by the 125I seed. 125I seed can inhibit cell growth mainly through the apoptotic pathway. The mechanism may involve the activation of p53 and its downstream apoptotic pathway by up-regulating the level of ROS in cells.

Mechanistic insights into 125I seed implantation therapy for Cholangiocarcinoma: focus on ROS-Mediated apoptosis and the role of GPX2.

OBJECTIVES: Cholangiocarcinoma (CCA) is a rare tumor with a poor prognosis and poses significant therapeutic challenges. Herein, we investigated the mechanism of efficacy of 125I seed implantation therapy in CCA, focusing on the induction of reactive oxygen species (ROS)-mediated apoptosis and the involvement of glutathione peroxidase 2 (GPX2). MATERIALS AND METHODS: Human cholangiocarcinoma cell lines QBC939 and RBE were purchased for in vitro studies. In vivo studies were performed using a rabbit VX2 CCA model. Apoptosis and proliferation were detected by TUNEL staining and clone formation, respectively. ROS generation was detected by dihydroethidium staining. Histological evaluation was performed by hematoxylin and eosin staining. Protein expression was determined by Western blotting and immunohistochemistry. RESULTS: Our results demonstrate that 125I seeds effectively inhibited tumor growth in the rabbit VX2 tumor model and promoted the apoptosis of CCA cells in vitro in a dose-dependent manner. Molecular analyses indicate a marked increase in reactive oxygen species (ROS) levels following treatment with 125I seeds, suggesting the involvement of ROS-mediated apoptosis in the therapeutic mechanism. Furthermore, the downregulation of glutathione peroxidase 2 (GPX2) was observed, indicating its potential role in modulating ROS-mediated apoptosis in CCA. CONCLUSION: 125I seed implantation therapy exerts therapeutic effects on CCA by inducing ROS-mediated apoptosis. The downregulation of GPX2 may contribute to enhanced ROS accumulation and apoptotic cell death. These findings provide mechanistic insights into the therapeutic potential of 125I seed implantation for CCA and highlight ROS-mediated apoptosis and GPX2 regulation as promising targets for further investigation and therapeutic intervention in this malignancy.

Hypofractionated Radiotherapy-Related Lymphopenia Is Associated With Worse Survival in Unresectable Intrahepatic Cholangiocarcinoma.

OBJECTIVE: The aim of this study was to evaluate the incidence of radiotherapy (RT)-related lymphopenia, its predictors, and association with survival in unresectable intrahepatic cholangiocarcinoma (ICC) treated with hypofractionated-RT (HF-RT). METHODS: Retrospective analysis of 96 patients with unresectable ICC who underwent HF-RT (median 58.05 Gy in 15 fractions) between 2009 and 2022 was performed. Absolute lymphocyte count (ALC) nadir within 12 weeks of RT was analyzed. Primary variable of interest was severe lymphopenia, defined as Grade 3+ (ALC <0.5 k/µL) per CTCAE v5.0. Primary outcome of interest was overall survival (OS) from RT. RESULTS: Median follow-up was 16 months. Fifty-two percent of patients had chemotherapy pre-RT, 23% during RT, and 40% post-RT. Pre-RT, median ALC was 1.1 k/µL and 5% had severe lymphopenia. Post-RT, 68% developed RT-related severe lymphopenia. Patients who developed severe lymphopenia had a significantly lower pre-RT ALC (median 1.1 vs. 1.5 k/µL, P =0.01) and larger target tumor volume (median 125 vs. 62 cm 3 , P =0.02). In our multivariable Cox model, severe lymphopenia was associated with a 1.7-fold increased risk of death ( P =0.04); 1-year OS rates were 63% vs 77% ( P =0.03). Receipt of photon versus proton-based RT (OR=3.50, P =0.02), higher mean liver dose (OR=1.19, P <0.01), and longer RT duration (OR=1.49, P =0.02) predicted severe lymphopenia. CONCLUSIONS: HF-RT-related lymphopenia is an independent prognostic factor for survival in patients with unresectable ICC. Patients with lower baseline ALC and larger tumor volume may be at increased risk, and use of proton therapy, minimizing mean liver dose, and avoiding treatment breaks may reduce RT-related lymphopenia.

Anti-PD-1 antibody in combination with radiotherapy as first-line therapy for unresectable intrahepatic cholangiocarcinoma.

BACKGROUND: Unresectable intrahepatic cholangiocarcinoma (iCCA) has a poor prognosis despite treatment with standard combination chemotherapy. We aimed to evaluate the efficacy and safety of radiotherapy in combination with an anti-PD-1 antibody in unresectable iCCA without distant metastases. METHODS: In this phase II study, patients with histopathologically confirmed unresectable primary or postoperative recurrent iCCA without distant metastases were enrolled. Patients received external radiotherapy with a dose of ≥45 Gy (2-2.5 Gy per fraction), followed by anti-PD-1 immunotherapy (camrelizumab 200 mg once, every 3 weeks) initiated within 7 days after completion of radiotherapy as first-line therapy. The primary endpoint was 1-year progression-free survival (PFS) rate. The secondary end points included safety, objective response rate (ORR), disease control rate (DCR), and overall survival (OS). RESULTS: From December 2019 to March 2021, 36 patients completed radiotherapy and at least one cycle of immunotherapy and were included in efficacy and safety analyses. The median follow-up was 19.0 months (IQR 12.0-24.0), and the one-year PFS rate was 44.4% (95% CI, 30.8-64.0). The median PFS was 12.0 months (95% CI, 7.5-not estimable); the median OS was 22.0 months (95% CI, 15.0-not estimable). The ORR was 61.1% and the DCR was 86.1%. Seventeen of 36 (47.2%) patients experienced treatment-related adverse effects (AEs) of any grade. The most common AE was reactive cutaneous capillary endothelial proliferation (25.0%). Five (13.9%) patients experienced grade ≥3 treatment-related AEs, including decreased lymphocyte (5.6%), bullous dermatitis (2.8%), decreased platelet count (2.8%), and deep-vein thrombosis (2.8%). CONCLUSIONS: External radiotherapy plus camrelizumab, as first-line therapy, met its primary endpoint and showed antitumor activity and low toxicity levels in patients with unresectable iCCA without distant metastases, warranting further investigation. TRIAL REGISTRATION: NCT03898895. Registered 2 April 2019.

Modified Radiation Lobectomy Strategy of Radioembolization for Right-Sided Unresectable Primary Liver Tumors.

PURPOSE: To assess the safety and effectiveness of using modified radiation lobectomy (mRL) to treat primary hepatic tumors located in the right hepatic lobe (Segments V-VIII) and to determine future liver remnant (FLR) hypertrophy. MATERIALS AND METHODS: A retrospective review was performed at a single institution to include 19 consecutive patients (7 females, 12 males) who underwent single-session mRL for right-sided primary hepatic tumors: 15 received segmentectomy plus lobectomy (segmental dose of >190 Gy and lobar dose of >80 Gy); 4 were treated with the double-segmental approach (dominant segments of >190 Gy and nondominant segments of >80 Gy). Treated tumors included 13 hepatocellular carcinoma (HCC), 4 cholangiocarcinoma (CCA), and 2 mixed-type HCC-CCA with a median dominant tumor size of 5.3 cm (interquartile range [IQR], 3.7-7.3 cm). FLR of the left hepatic lobe was measured at baseline, T1 (4-8 weeks), T2 (2-4 months), T3 (4-6 months), and T4 (9-12 months). RESULTS: Objective tumor response and tumor control were achieved in 17 of the 19 (89.5%) and 18 of the 19 (94.7%) patients, respectively. FLR hypertrophy was observed at T1 (median, 47.8%; P = .025), T2 (median, 48.4%; P = .012), T3 (median, 50.4%; P = .015), and T4 (median, 59.1%; P < .001). Patients without cirrhosis demonstrated greater hypertrophy by 6 months (median, 55.8% vs 47.2%; P = .031). One patient developed a Grade 3 adverse event (ascites requiring paracentesis) at 1-month follow-up. Grade ≥2 serum toxicities were associated with worse baseline Child-Pugh Score, serum albumin, and total bilirubin (P < .05). Among 7 patients who underwent neoadjuvant mRL, 2 underwent resection and 1 received liver transplant. CONCLUSIONS: mRL appears safe and effective for treatment of right-sided primary hepatic tumors with the benefit of promoting FLR hypertrophy.

Stent Insertion for Inoperable Hilar Cholangiocarcinoma: Comparison Between Unilateral Radioactive Stent and Bilateral Normal Stent.

OBJECTIVE: To comparatively analyze the clinical efficacy and safety of unilateral radioactive stent (RS) insertion versus bilateral normal stent (NS) insertion in patients with inoperable hilar cholangiocarcinoma (HC). PATIENTS AND METHODS: Patients with inoperable HC were treated in our hospital from January 2016 to December 2020. The treatment approach included the insertion of either unilateral RS or bilateral NS, evaluating the efficacy and safety of therapy in 2 distinct groups. RESULTS: A total of 58 individuals experienced the insertion of a unilateral RS, whereas 57 patients underwent the insertion of bilateral NS. No statistically significant difference between the unilateral RS and bilateral NS groups was seen in the technical success rates (98.3% vs 94.7%, P = 0.598) and clinical success rates (98.2% vs 100%, P = 0.514). While there is no statistically significant difference in the rates of stent restenosis (19.3% vs 9.3%, P = 0.132) between the two groups, the unilateral RS group demonstrated substantially longer stent patency (202 vs 119 d, P = 0.016) and overall survival (229 vs 122 d, P = 0.004) compared with the bilateral NS group. Moreover, 8 patients (14.0%) in the unilateral RS group and 14 patients (25.9%) in the bilateral NS group had postoperative complications with no significant difference ( P = 0.116). CONCLUSION: When inserting stents for inoperable HC, both unilateral RS and bilateral NS insertion procedures have demonstrated favorable therapeutic efficacy. Nevertheless, inserting a unilateral RS provided a longer duration of stent patency and overall survival than implantation of bilateral NS.

Factors Impacting Survival After Transarterial Radioembolization in Patients with Unresectable Intrahepatic Cholangiocarcinoma: A Combined Analysis of the Prospective CIRT Studies.

PURPOSE: Transarterial radioembolization (TARE) with Yttrium-90 resin microspheres is a treatment option for patients with intrahepatic cholangiocarcinoma (ICC). However, optimising the timing of TARE in relation to systemic therapies and patient selection remains challenging. We report here on the effectiveness, safety, and prognostic factors associated with TARE for ICC in a combined analysis of the prospective observational CIRT studies (NCT02305459 and NCT03256994). METHODS: A combined analysis of 174 unresectable ICC patients enrolled between 2015 and 2020 was performed. Patient characteristics and treatment-related data were collected at baseline; adverse events and time-to-event data (overall survival [OS], progression-free survival [PFS] and hepatic PFS) were collected at every follow-up visit. Log-rank tests and a multivariable Cox proportional hazard model were used to identify prognostic factors. RESULTS: Patients receiving a first-line strategy of TARE in addition to any systemic treatment had a median OS and PFS of 32.5 months and 11.3 months. Patients selected for first-line TARE alone showed a median OS and PFS of 16.2 months and 7.4 months, whereas TARE as 2nd or further treatment-line resulted in a median OS and PFS of 12 and 9.3 months (p = 0.0028), and 5.1 and 3.5 months (p = 0.0012), respectively. Partition model dosimetry was an independent predictor for better OS (HR 0.59 [95% CI 0.37-0.94], p = 0.0259). No extrahepatic disease, no ascites, and < 6.1 months from diagnosis to treatment were independent predictors for longer PFS. CONCLUSION: This combined analysis indicates that in unresectable ICC, TARE in combination with any systemic treatment is a promising treatment option. LEVEL OF EVIDENCE: level 3, Prospective observational.

Comparison of 3 Different Therapeutic Particles in Radioembolization of Locally Advanced Intrahepatic Cholangiocarcinoma.

Our objective was to compare 3 different therapeutic particles used for radioembolization in locally advanced intrahepatic cholangiocarcinoma. Methods: 90Y-glass, 90Y-resin, and 166Ho-labeled poly(l-lactic acid) microsphere prescribed activity was calculated as per manufacturer recommendations. Posttreatment quantitative 90Y PET/CT and quantitative 166Ho SPECT/CT were used to determine tumor-absorbed dose, whole-normal-liver-absorbed dose, treated-normal-liver-absorbed dose, tumor-to-nontumor ratio, lung-absorbed dose, and lung shunt fraction. Response was assessed using RECIST 1.1 and the [18F]FDG PET-based change in total lesion glycolysis. Hepatotoxicity was assessed using the radioembolization-induced liver disease classification. Results: Six 90Y-glass, 8 90Y-resin, and 7 166Ho microsphere patients were included for analysis. The mean administered activity was 2.6 GBq for 90Y-glass, 1.5 GBq for 90Y-resin, and 7.0 GBq for 166Ho microspheres. Tumor-absorbed dose and treated-normal-liver-absorbed dose were significantly higher for 90Y-glass than for 90Y-resin and 166Ho microspheres (mean tumor-absorbed dose, 197 Gy for 90Y-glass vs. 73 Gy for 90Y-resin and 50 Gy for 166Ho; mean treated-normal-liver-absorbed dose, 79 Gy for 90Y-glass vs. 37 Gy for 90Y-resin and 31 Gy for 166Ho). The whole-normal-liver-absorbed dose and tumor-to-nontumor ratio did not significantly differ between the particles. All patients had a lung-absorbed dose under 30 Gy and a lung shunt fraction under 20%. The 3 groups showed similar toxicity and response according to RECIST 1.1 and [18F]FDG PET-based total lesion glycolysis changes. Conclusion: The therapeutic particles used for radioembolization differed from each other and showed significant differences in absorbed dose, whereas toxicity and response were similar for all groups. This finding emphasizes the need for separate dose constraints and dose targets for each particle.

Chemotherapy with or without selective internal radiation therapy for intrahepatic cholangiocarcinoma: Data from clinical trials.

BACKGOUND AND AIMS: In advanced, liver-only intrahepatic cholangiocarcinoma (iCCA), selective internal radiation therapy (SIRT) has been suggested as promising in nonrandomized studies. We aimed to compare data from patients with advanced, liver-only iCCA treated in the first line in clinical trials with either chemotherapy alone or the combination with SIRT. APPROACH AND RESULTS: We collected individual patients' data from the ABC-01, ABC-02, ABC-03, BINGO, AMEBICA, and MISPHEC prospective trials. Data from patients with liver-only iCCA treated in chemotherapy-only arms of the first 5 trials were compared with data from patients treated with SIRT and chemotherapy in MISPHEC. Emulated target trial paradigm and Inverse Probability of Treatment Weighting (IPTW methods) using the propensity score were used to minimize biases. We compared 41 patients treated with the combination with 73 patients treated with chemotherapy alone, the main analysis being in 43 patients treated with cisplatin-gemcitabine or gemcitabine-oxaliplatin. After weighting, overall survival was significantly higher in patients treated with SIRT: median 21.7 months (95% CI: 14.1; not reached) versus 15.9 months(95% CI: 9.8; 18.9), HR = 0.59 (95% CI: 0.34; 0.99), p = 0.049. Progression-free survival was significantly improved: median 14.3 months (95% CI: 7.8; not reached) versus 8.4 months (95% CI: 5.9; 12.1), HR = 0.52 (95% CI: 0.31; 0.89), p < 0.001. Results were confirmed in most sensitivity analyses. CONCLUSIONS: This analysis derived from prospective clinical trials suggests that SIRT combined with chemotherapy might improve outcomes over chemotherapy alone in patients with advanced, liver-only iCCA. Randomized controlled evidence is needed to confirm these findings.

Selective internal radiation therapy using yttrium-90 microspheres for treatment of localized and locally advanced intrahepatic cholangiocarcinoma.

OBJECTIVES: To evaluate safety and effectiveness of selective internal radiation therapy (SIRT) using yttrium-90 for localized and locally advanced intrahepatic cholangiocarcinoma (iCCA). METHODS: A retrospective review was performed of patients with localized iCCA treated with SIRT at a single institution. Overall survival (OS), local tumor response, progression-free survival (PFS), and toxicity were collected. Stratified analysis was performed based on surgical resection. Predictor analysis of OS was performed using the Fine-Grey regression analysis model with patients bridged to surgery regarded as competing events. RESULTS: A total of 28 consecutive patients with localized iCCA were treated with a total of 38 sessions of SIRT (17 segmental, 13 lobar, and 8 combined deliveries) and a mean dominant target dose per session of 238.4 ± 130.0 Gy. The cumulative radiologic response rate was 16/28 (57.1%) with a median PFS of 265 days. Median survival time (MST) was 22.9 months for the entire cohort with 1-year and 3-year survival of 78.4% and 45.1%, respectively. Ten patients (34.5%) were downstaged to surgical intervention (7 resection, 3 transplant) and showed longer OS (p = 0.027). The 1-year and 3-year OS for patients who received surgery were 100% and 62.5% (95% CI: 14.2-89.3%), respectively. Age (p = 0.028), Eastern Cooperative Oncology Group performance status (p = 0.030), and objective radiologic response (p=0.014) are associated with OS. Two ≥grade 3 hyperbilirubinemia, anemia, and one pleuro-biliary fistula occurred post-SIRT. CONCLUSIONS: SIRT for localized iCCA is safe and effective in achieving radiological response, downstaging to surgery and transplant, and resulting in pathologic necrosis. CLINICAL RELEVANCE STATEMENT: Selective internal radiation therapy should be considered for patients with localized and locally advanced intrahepatic cholangiocarcinoma. KEY POINTS: • The effectiveness of radioembolization for intrahepatic cholangiocarcinoma (iCCA) can be underestimated given the inclusion of extrahepatic disease. • Radioembolization is safe and effective for local and locally advanced iCCA. Age, Eastern Cooperative Oncology Group performance status, and radiologic response are associated with survival. • Radioembolization should be considered for patients with localized and locally advanced iCCA.

Single center experience using stereotactic body radiation therapy (SBRT) on orthotopic liver transplant protocol for unresectable cholangiocarcinoma.

PURPOSE: To evaluate tolerability, pathologic response, and disease outcomes utilizing pre-operative stereotactic body radiation therapy (SBRT) followed by consolidation chemotherapy (CHT) prior to orthotopic liver transplant (OLT) in unresectable cholangiocarcinoma (CCA). METHODS: This was a retrospective chart review of patients treated on OLT protocol at a single tertiary center from 2012 to 2019. Patients received pre-operative SBRT (40-50 Gy in 5 fractions) followed by CHT until progression or OLT. Progression-free survival (PFS) and overall survival (OS) were compared via log-rank test and Cox proportional hazards regression. RESULTS: 26 patients (84.6% hilar, 15.4% intrahepatic) were identified for analysis. Eight patients (30.8%) patients developed acute toxicity after SBRT, mostly grade 1 nausea. Nine (34.6%) patients underwent OLT of which 4 (44.4%) achieved a pathologic complete response (pCR). Five (55.6%) OLT patients, including 2 pCR, developed recurrence at a median time of 49.9 weeks after OLT. 3-year OS for the OLT and dropout cohort was 75% and 9%, respectively (p < 0.0001). OS in hilar tumors only was statistically different for those that achieved a pCR (p = 0.014). CONCLUSIONS: Pre-operative SBRT is a well-tolerated and effective radiation technique as part of OLT protocol for unresectable CCA and conferred in a pCR rate of 44% within our cohort.

Trends in Selective Internal Radiation Therapy (SIRT) for Treating Hepatocellular Carcinoma, Cholangiocarcinoma, and Liver Metastasis: A Total Population Analysis from 2006 to 2021 in Germany.

The aim of this study was to investigate trends in selective internal radiation therapy (SIRT) for hepatocellular carcinoma (HCC), cholangiocarcinoma (CCC), and liver metastasis in Germany. We analyzed the nationwide German hospital billing database from 2006 to 2019 for the diagnosis of HCC, CCC or liver metastasis in combination with SIRT. For analyses of SIRT on the hospital level, we used the reimbursement.INFO tool based on German hospitals' quality reports from 2008 to 2021. Linear regression analysis was performed to detect changes over time. We included a total of 14,165 SIRT procedures. The annual numbers increased from 99 in 2006 to 1605 in 2015 (p < 0.001; increase by 1521%), decreasing to 1175 cases in 2019 (p < 0.001). In 2008, 6 of 21 hospitals (28.6%) performed more than 20 SIRTs per year, which increased to 19 of 53 (35.8%) in 2021. The share of SIRT for HCC increased from 29.8% in 2006 to 44.7% in 2019 (p < 0.001) and for CCC from 0% in 2006 to 9.5% in 2019 (p < 0.001), while the share of SIRT for liver metastasis decreased from 70.2% in 2006 to 45.7% in 2019 (p < 0.001). In-hospital mortality was 0.2% after the SIRT procedure. Gastritis (2.7%), liver failure (0.4%), and sepsis (0.3%) were the most common in-hospital complications reported. We observed an increase in SIRT procedures in Germany, with the number of hospitals offering the procedure going up from 21 in 2008 to 53 in 2021. While the treatment of liver metastasis remains the most common indication, SIRT for HCC and CCC increased significantly over the last few years. The mortality and complication rates show that SIRT is a relatively safe procedure.

What Role Does Radiotherapy Play in the Molecular Era for Intrahepatic Cholangiocarcinoma?

ABSTRACT: Intrahepatic cholangiocarcinoma is a rare disease, yet with rising incidence globally. Most patients are not eligible for potentially curative surgical resection, and many patients with unresectable disease die within 12 months of diagnosis, primarily due to liver failure from the primary tumor. Recent prospective and retrospective studies indicate that local control of the primary tumor can be achieved with hypofractionated radiotherapy in patients with unresectable disease, translating into prolonged survival of these patients. During the time that these encouraging reports for radiotherapy have been published, numerous concurrent studies have also shown that intrahepatic cholangiocarcinoma is a molecularly diverse disease with multiple targetable genetic alterations and a complex tumor microenvironment. These biological insights have translated into new drug approvals for subsets of patients. We review the current knowledge about the biology and targeted treatment of intrahepatic cholangiocarcinoma and describe these developments in the context of modern radiotherapy.

Segmental Yttrium-90 Radioembolization Using Glass Microspheres Greater than 400 Gray for the Treatment of Intrahepatic Cholangiocarcinoma: A Preliminary Experience.

Radiation segmentectomy with a dose of >190 Gy using yttrium-90 (90Y) glass microspheres for intrahepatic cholangiocarcinoma (iCCA) has been shown to be safe and effective. The present study further increased the dose to >400 Gy for treatment of iCCA as complete pathologic necrosis has been shown in hepatocellular carcinoma using this ablative approach. A total of 10 patients with 13 tumors (median size, 5.3 cm; range, 1.5-13.6 cm) at a single institution underwent >400-Gy segmental radioembolization. Objective response was achieved in all tumors (13 of 13, 100%). One patient developed a Grade 3 or greater major adverse event (stroke and hepatic decompensation). One patient was bridged to transplant (>95% pathologic necrosis), whereas another underwent resection (>99% necrosis). Contralateral hypertrophy was observed in 6 out of 6 patients treated with modified lobectomy dosing, with a functional liver reserve increase from a median of 31.5% to 57.1%. The present report suggests that segmental transarterial radioembolization with >400 Gy is feasible in terms of safety and effectiveness for treating iCCA.

Comparing Survival After Resection, Ablation, and Radiation in Small Intrahepatic Cholangiocarcinoma.

BACKGROUND: Hepatectomy is the cornerstone of curative-intent treatment for intrahepatic cholangiocarcinoma (ICC). However, in patients unable to be resected, data comparing efficacy of alternatives including thermal ablation and radiation therapy (RT) remain limited. Herein, we compared survival between resection and other liver-directed therapies for small ICC within a national cancer registry. PATIENTS AND METHODS: Patients with clinical stage I-III ICC < 3 cm diagnosed 2010-2018 who underwent resection, ablation, or RT were identified in the National Cancer Database. Overall survival (OS) was compared using Kaplan-Meier and multivariable Cox proportional hazards methods. RESULTS: Of 545 patients, 297 (54.5%) underwent resection, 114 (20.9%) ablation, and 134 (24.6%) RT. Median OS was similar between resection and ablation [50.5 months, 95% confidence interval (CI) 37.5-73.9; 39.5 months, 95% CI 28.7-58.4, p = 0.14], both exceeding that of RT (20.9 months, 95% CI 14.1-28.3). RT patients had high rates of stage III disease (10.4% RT vs. 1.8% ablation vs. 11.8% resection, p < 0.001), but the lowest rates of chemotherapy utilization (9.0% RT vs. 15.8% ablation vs. 38.7% resection, p < 0.001). In multivariable analysis, resection and ablation were associated with reduced mortality compared with RT [hazard ratio (HR) 0.44, 95% CI 0.33-0.58 and HR 0.53, 95% CI 0.38-0.75, p < 0.001, respectively]. CONCLUSION: Resection and ablation were associated with improved survival in patients with ICC < 3 cm compared with RT. Acknowledging confounders, anatomic constraints of ablation, limitations of available data, and need for prospective study, these results favor ablation in small ICC where resection is not feasible.

Factors affecting outcomes of Yttrium-90 radioembolization in heavily pretreated patients with intrahepatic cholangiocarcinoma.

PURPOSE: Transarterial radioembolization (TARE) is a liver-directed treatment for unresectable intrahepatic cholangiocarcinoma (ICC). The aim of this study is to evaluate factors affecting outcomes of TARE in heavily pretreated ICC patients. METHODS: We evaluated pretreated ICC patients who received TARE from January 2013 to December 2021. Prior treatments included systemic therapy, hepatic resection, and liver-directed therapies, including hepatic arterial infusion chemotherapy, external beam radiation, transarterial embolization, and thermal ablation. Patients were classified based on history of hepatic resection and genomic status based on next-generation sequencing (NGS). The primary endpoint was overall survival (OS) after TARE. RESULTS: Fourteen patients with median age 66.1 years (range, 52.4-87.5), 11 females and 3 males, were included. Prior therapies included systemic in 13/14 patients (93%), liver resection in 6/14 (43%), and liver-directed therapy in 6/14 (43%). Median OS was 11.9 months (range, 2.8-81.0). Resected patients had significantly longer median OS compared to unresected patients (16.6 versus 7.9 months; p = 0.038). Prior liver-directed therapy (p = 0.043), largest tumor diameter > 4 cm (p = 0.014), and > 2 hepatic segments involvement (p = 0.001) were associated with worse OS. Nine patients underwent NGS; 3/9 (33.3%) and had a high-risk gene signature (HRGS), defined as alterations in TP53, KRAS, or CDKN2A. Patients with a HRGS had worse median OS (10.0 versus 17.8 months; p = 0.024). CONCLUSIONS: TARE may be used as salvage therapy in heavily treated ICC patients. Presence of a HRGS may predict worse OS after TARE. Further investigation with more patients is recommended to validate these results.

Radioembolization with Yttrium-90 Glass Microspheres as a First-Line Treatment for Unresectable Intrahepatic Cholangiocarcinoma-A Prospective Feasibility Study.

PURPOSE: To evaluate the safety and effectiveness of yttrium-90 (90Y) radioembolization as first-line treatment for unresectable intrahepatic cholangiocarcinoma (ICC). MATERIALS AND METHODS: This prospective study enrolled patients who had never received chemotherapy, liver embolization, and radiation therapy. The tumors were solitary in 16 patients, multiple in 8 patients, unilobar in 14 patients, and bilobar in 10 patients. Patients underwent transarterial radioembolization with 90Y-labeled glass microspheres. The primary end point was hepatic progression-free survival (HPFS). Secondary end points were overall survival (OS), tumor response, and toxicity. RESULTS: Twenty-four patients (age, 72.3 years ± 9.3; 12 women) were included in the study. The median delivered radiation dose was 135.5 Gy (interquartile range, 77.6 Gy). The median HPFS was 5.5 months (95% CI, 3.9-7.0 months). Analysis failed to identify any prognostic factor associated with HPFS. Imaging response at 3 months showed 56% disease control, and the best radiographic response was 71% disease control. The median OS from the radioembolization treatment was 19.4 months (95% CI, 5.0-33.7). Patients with solitary ICC had significantly longer median OS than patients with multifocal ICC: 25.9 months (95% CI, 20.8-31.0 months) versus 10.7 months (95% CI, 8.0-13.4 months) (P = .02). Patients with progression on the 3-month imaging follow-up had significantly shorter median OS than patients who had stable disease at 3 months: 10.7 months (95% CI, 0.7-20.7 months) versus 37.3 months (95% CI, 16.5-58.1 months) (P = .003). Two (8%) Grade 3 toxicities were reported. CONCLUSIONS: First-line treatment of ICC with radioembolization showed promising OS and minimal toxicity, especially in patients with solitary tumor. Radioembolization may be considered as a first-line treatment option for unresectable ICC.

Ablative radiotherapy for colorectal liver metastases and intrahepatic cholangiocarcinoma.

The role of radiation therapy in the management of liver cancers, both primary and metastatic, has changed drastically over the past several decades. Although conventional radiation was limited by technology, the advent of advanced image-guided radiotherapy and the rise in evidence for and popularity of stereotactic body radiotherapy have expanded the indications for radiation in these two distinct disease types. Magnetic resonance imaging-guided radiation therapy, daily online adaptive radiotherapy, and proton radiotherapy are some of many modern radiotherapy techniques that allow for increasingly efficacious treatment of intrahepatic disease while simultaneously allowing for increased normal tissue sparing, including sparing of the normal liver and the radiosensitive luminal gastrointestinal tract. Modern radiation therapy should be considered along with approaches such as surgical resection and radiofrequency ablation for the management of liver cancers of diverse histologies. Herein we describe the use of modern radiotherapy in two example settings, colorectal liver metastases and intrahepatic cholangiocarcinoma, and how external beam radiotherapy provides options within multidisciplinary discussions to elect optimal patient-specific treatments.