Evaluation of Medium-Term Efficacy of Y90 Radiation Segmentectomy vs Percutaneous Microwave Ablation in Patients with Solitary Surgically Unresectable < 4 cm Hepatocellular Carcinoma: A Propensity Score Matched Study

Radiation segmentectomy for early hepatocellular carcinoma is curative

In this expert opinion, we provide the rationale for concluding that radiation segmentectomy (using the RADSEG method) - a technique involving the transarterial delivery of an ablative, complete necrosis-inducing dose of yttrium-90 radiotherapy - is curative in limited-disease burden hepatocellular carcinoma (HCC). Currently, curative options for early stage and other carefully selected HCC cases include transplantation, resection, and ablation. Because of issues with organ availability, co-morbidities preventing resection, and tumour size and location limiting ablation, other treatments are necessary for this selected patient population. The RADSEG method has evolved into an intra-arterial approach in this setting, with long-term outcomes comparable to ablation, resection, and transplantation. It is proposed that yttrium-90 radioembolisation, applying the RADSEG technique, be formally recognised as curative for early HCC.

Radiation Segmentectomy or Ablative External Beam Radiation Therapy as Initial Treatment for Solitary Hepatocellular Carcinoma: A Multicenter Experience

Purpose

Radiation segmentectomy (RS) and ablative external beam radiation therapy (EBRT) are now accepted, definitive, local therapies for hepatocellular carcinoma (HCC). This report aimed to describe the clinical outcomes of RS and EBRT for treatment-naïve, solitary, HCC.

Methods

A multicenter retrospective review was performed of all patients treated with RS or EBRT from March 2016 through September 2023. Inclusion criteria were initial treatment for solitary HCC ≤8 cm and absence of macrovascular invasion or extrahepatic disease. Outcomes were censored for liver transplantation (LT).

Results

Eighty-six patients (RS: 58; EBRT: 28) met inclusion criteria. The EBRT cohort had older patients (median 76 vs 66 years, p < 0.001), larger tumors (median 3.7 vs 2.4 cm, p < 0.001), and worse performance status (p = 0.02). The RS cohort had more patients with ≥ grade 3 liver fibrosis (p < 0.001). Radiologic complete response (rCR) was achieved in 97% of RS and 82% of EBRT patients (p = 0.02). Median time to rCR was 1 month (95% CI: 0.9-1.1) after RS and 7 months (95% CI: 6-7) after EBRT (p < 0.001). The 1-year local control was 97% vs 93% for RS and EBRT, respectively (p = 0.80). Subsequent LT was performed in 48% of RS and 11% of EBRT patients with tumor complete pathologic response rates of 76% (n=22/28) and 33% (n=1/3), respectively. Progression free survival at 1-year was 87% after RS vs 80% after EBRT (p = 0.26). 1- and 2-year overall survival was 88% and 85% after RS vs 84% and 59% after EBRT (p = 0.34).

Conclusion

RS and EBRT are effective therapies for solitary HCC. Treatment should be determined via multidisciplinary discussion based on individual patient characteristics.

Radioembolization of HCC and secondary hepatic tumors: a comprehensive review

Transarterial radioembolization (TARE), also called Selective Internal Radiation Therapy (SIRT), has emerged as an effective locoregional therapy for primary and secondary hepatic tumors, utilizing yttrium-90 (Y90) microspheres and other agents such as holmium-166 and rhenium-188. TARE has various applications in the management of HCC across different BCLC stages. Radiation segmentectomy, which involves administering high doses of Y90 (>190 Gy), can be both curative and ablative, achieving complete necrosis of the tumor. In contrast, radiation lobectomy involves administering a lower dose of Y90 (80-120 Gy) as a neoadjuvant treatment modality to improve local control and induce future liver remnant (FLR) hypertrophy in patients who are planned to undergo surgery but have insufficient FLR. Modified radiation lobectomy combines both techniques and offers several advantages over portal vein embolization (PVE). Y90 is also used in downstaging HCC patients outside liver transplantation criteria, as well as bridging those awaiting liver transplantation (LT). Multiple studies and combined analyses were described to highlight the outcomes of TARE and compare it with other treatment modalities, including TACE and sorafenib. Additionally, the review delves into the efficacy and safety of radioembolization in managing metastatic colorectal cancer and other metastatic tumors to the liver. Recent studies have emphasized the role of personalized dosimetry for improved outcomes, and thus we described the different methods used for this purpose. Pretherapy imaging, estimating lung shunt, selection of therapeutic radionuclides, adverse effects, and cost-effectiveness were all discussed as well.

Locoregional Therapies for Hepatocellular Carcinoma prior to Liver Transplant: Comparative Pathologic Necrosis, Radiologic Response, and Recurrence

PURPOSE

To compare pathologic tumor necrosis rates after locoregional therapies (LRTs) for hepatocellular carcinoma (HCC) prior to liver transplantation and evaluate radiologic-pathologic correlation along with posttransplant HCC recurrence.

MATERIALS AND METHODS

Consecutive patients with solitary HCC bridged or downstaged with LRT from 2010 to 2022 were included. LRTs were transarterial chemoembolization (TACE), radioembolization (yttrium-90 [90Y]), ablation, and stereotactic body radiotherapy (SBRT). Upfront combination therapy options were TACE/ablation and TACE/SBRT. Subsequent therapy crossover due to local recurrence was allowed. Posttreatment imaging closest to the time of transplant, explant histopathologic necrosis, and tumor recurrence after transplant were reviewed.

RESULTS

Seventy-three patients met inclusion criteria, of whom 5 (7%) required downstaging. 90Y alone (n = 36) and multimodal therapy (pooled upfront combination and crossover therapy, n = 23) resulted in significantly greater pathologic necrosis compared with TACE alone (n = 14; P = .01). High dose 90Y radiation segmentectomy (≥190 Gy; n = 27) and TACE/ablation (n = 7) showed highest rates of complete pathologic necrosis (CPN)-63% (n = 17) and 71% (n = 5), respectively. Patients with CPN had a mean lesion size of 2.5 cm, compared with 3.2 cm without CPN (P = .04), irrespective of LRT modality. HCC recurrence was more common in patients without CPN (16%, 6/37) than in those with CPN (3%, 1/36; P = .11). Using Liver Imaging Reporting and Data System (LI-RADS), a nonviable imaging response was 75% sensitive and 57% specific for CPN.

CONCLUSIONS

Radiation segmentectomy and multimodal therapy significantly improved CPN rates compared with TACE alone. A LI-RADS treatment response of nonviable did not confidently predict CPN.

Tumor Size and Watershed Area Correlate with Incomplete Treatment and Tumor Progression after Selective Radioembolization for Hepatocellular Carcinoma

PURPOSE

To identify factors of incomplete treatment after segmental transarterial radioembolization (TARE) for treatment-naive and solitary hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

A total of 75 consecutive patients (age, 68.5 years [SD ± 8.0]; 25/75 [33.3%] women) with treatment-naive, solitary HCC underwent segmental or subsegmental TARE with glass microspheres (tumor size, 3.8 cm [SD ± 2.2]; administered dose, 222.6 Gy [SD ± 123.9]) at a single institution from November 2015 to June 2022. Radiologic response and progression-free survival (PFS) were assessed as per modified Response Evaluation Criteria in Solid Tumors.

RESULTS

Complete treatment was achieved in 48 of 75 (64.0%) patients (mean follow-up, 33.2 months [SD ± 27.4]). Patients with incomplete treatment (27/75, 36%) presented with larger tumor size (5.0 [SD ± 2.5] vs 3.1 [SD ± 1.6] cm; P = .0001), with more tumors located in the watershed zone (81.5% vs 41.7%; P = .001). These patients were less likely to be bridged to transplant or resection (22.2% vs 52.1%; P = .015). Watershed tumors demonstrated worse target tumor PFS (median PFS, 19 months vs not reached; P = .0104) and overall PFS (9.1 months vs not reached; P = .0077). Watershed location was associated with worse PFS among tumors >3 cm in size (8.4 months vs not reached; P = .035) but not in tumors ≤3 cm in size (52.2 months vs not reached; P = .915).

CONCLUSIONS

Tumor size and watershed location were associated with incomplete treatment after segmental TARE for HCC. Watershed tumors were associated with worse PFS, particularly tumors larger than 3 cm. These tumors may require careful treatment planning and repeated treatments to ensure a durable response.

Radiation Segmentectomy for the Treatment of Hepatocellular Carcinoma: A Practical Review of Evidence

Radiation segmentectomy is a versatile, safe, and effective ablative therapy for early-stage hepatocellular carcinoma. Advances in radiation segmentectomy patient selection, procedural technique, and dosimetry have positioned this modality as a curative-intent and guideline-supported treatment for patients with solitary HCC. This review describes key radiation segmentectomy concepts and summarizes the existing literary knowledgebase.

Radiation Segmentectomy for Hepatocellular Carcinoma

The application of trans-arterial radioembolization (TARE) with Yttrium-90, historically a palliative treatment option for patients with advanced hepatocellular carcinoma (HCC), is evolving. Radiation segmentectomy (RADSEG), the segmental delivery of an ablative radiation dose, is a treatment option for patients with earlier-stage HCC. This review presents an in-depth exploration of RADSEG, emphasizing its technical considerations, dosimetry advancements, and patient selection. The integration of RADSEG into the Barcelona Clinic Liver Cancer (BCLC) paradigm will be highlighted. RADSEG outcomes concerning safety and efficacy will be explored and compared with traditional locoregional cancer treatments like trans-arterial chemoembolization (TACE), percutaneous thermal ablation, and surgical resection, with an eye on future directions and considerations.

Ablation versus Radiation Segmentectomy for Small Liver Tumors

Hepatocellular carcinoma (HCC) is a liver malignancy that affects more than a million people worldwide with a complex multifactorial etiology. After the diagnosis of HCC is made, physicians establish management using the Barcelona Clinic Liver Cancer (BCLC) guidelines revolving around tumor stage, liver function, performance status, and patient preferences. According to recent updates to these guidelines, thermal ablation is the second-best curative option apart from surgical resection for small HCC (< 2 cm). While thermal ablation is standard of care, recent studies have suggested that radiation segmentectomy (RS) has similar outcomes, limited hepatotoxicity, and ultimately a cost-efficient approach. Although there is limited literature on RS, this article compares ablation techniques against radiation segmentectomy for small HCC tumors.

Optimal treatment for small HCC (<3 cm): Resection, liver transplantation, or locoregional therapy?

Hepatocellular carcinoma (HCC) remains the most common form of liver cancer, accounting for 90% of all primary liver cancers. Up to 30% of HCC cases could be small (2-3 cm in diameter) at the time of diagnosis with advances in imaging techniques and surveillance programmes. Treating patients with early-stage HCC can be complex and often requires interdisciplinary care, owing to the wide and increasing variety of treatment options, which include liver resection, liver transplantation, and various locoregional therapies offered by interventional radiology and radiation oncology. Decisions regarding the optimal management strategy for a patient involve many considerations, including patient- and tumour-specific characteristics, as well as socioeconomic factors. In this review, we aim to comprehensively summarise the commonly used therapies for single, small HCC (<3 cm), with a focus on the impact of tumour size (<2 cm vs. 2-3 cm), as well as a brief discussion on the cost-effectiveness of the different treatment options.

Microwave ablation for hepatic malignancies: a systematic review of the technology and differences in devices

BACKGROUND

Microwave ablation (MWA) has become the standard thermal-based treatment for hepatic malignancies in patients who have unresectable disease based on the biology of the tumor, the patients' comorbidities, and certain disease sites. The technical effectiveness, ablation success, local recurrence rates of hepatic malignancies treated with the various commercial microwave ablation devices has not been previously published in the peer reviewed literature. The aim of this systematic review is to summarize the clinical outcomes for the various MWA devices in the use of a hepatic malignancies to best educate hepatic surgeons as well as interventional radiologists.

METHODS

A comprehensive review of the literature and instructions for use of each device that was published from 1/2013 to 12/2020 was performed. The main outcomes extracted were technical success, ablation success, major complications, local and new recurrence rates, recurrence-free survival, ablation volumes, time, and the number of antennas required. A qualitative review of the literature was performed.

RESULTS

In total, 29 studies reporting data on 3250 patients and 4500 tumors were included in this review. Median patient age was 60.5 years (range 3-91). 76.3% (2420 M/753 F) of patients were male. Hepatocellular carcinoma (55%) was the most common tumor pathology followed by colorectal liver metastasis (10%) and cholangiocarcinoma (4%). A majority of studies reported technical success (range, 91.6-100%) and ablation success (range, 73.1-100%), as well as major complications (range, 0-9.1%). Local recurrence (range, 0-50%) was reported by 21 of the studies; however, new recurrence (range, 12.2-64%) was reported less frequently (6 studies) and were further specified in 12, six, and four studies as intrahepatic distant recurrence (11.3-54.2%), extrahepatic distant recurrence (3.6-20%), and metastasis (1.1-36%). A total of three, six, and five studies report disease, progression, and recurrence-free survival rates, respectively.

CONCLUSION

Microwave ablation is frequently used for the treatment of hepatic malignancies. A thorough understanding of the clinical outcomes associated with different pathologies and MWA devices can improve surgeon awareness and help prepare for operative planning and patient management. More consistent reporting of key outcomes in the literature is needed to achieve such an understanding.

Radiation Segmentectomy for the Treatment of Solitary Hepatocellular Carcinoma: Can Outcomes Be Compared to Surgical Resection?

PURPOSE

To investigate outcomes of radiation segmentectomy (RS) versus standard-of-care surgical resection (SR) as a quality endeavor.

MATERIALS AND METHODS

A multisite, retrospective, analysis of treatment-naïve patients who received either RS or SR was performed. Inclusion criteria were solitary HCC ≤8 cm, Eastern Cooperative Oncology Cohort performance status 0-1, and absence of macrovascular invasion or extrahepatic disease. Target tumor and overall progression, time-to-progression (TTP), and overall survival were assessed. Outcomes were censored for liver transplantation.

RESULTS

123 patients were included (RS:57, SR:66). Tumor size, Child-Pugh class, ALBI score, platelet count, and fibrosis stage were significantly different between cohorts (p≤0.01). Grade ≥3 adverse events per Clavien-Dindo classification occurred in 0 RS vs 13(20%) SR patients. Target tumor progression occurred in 3(5%) RS and 5(8%) SR patients, and overall progression in 19(33%) RS and 21(32%) SR patients. Median overall TTP was 21.9 and 29.4 months after RS and SR, respectively (95%CI:15.5-28.2 and 95%CI:18.5-40.3, p=0.03). Overall TTP subgroup analyses showed no difference between cohorts with fibrosis stage 3-4 (p=0.26) and platelets <150x10⁹/L (p=0.29). The overall progression hazard ratio for RS vs SR was not significant per multivariate cox regression analysis (1.16, 95%CI:0.51-2.63, p=0.71). Median overall survival was not reached for either cohort. Propensity scores were calculated but were too dissimilar for matching.

CONCLUSION

Radiation segmentectomy and surgical resection are performed in different patient populations, which limits comparison. Radiation segmentectomy approaches surgical resection outcomes, with a lower incidence of major adverse events, in patients who are not eligible for hepatectomy.

Contrast-enhanced ultrasound (CEUS) in HCC diagnosis and assessment of tumor response to locoregional therapies

Hepatocellular carcinoma (HCC) is a global problem constituting the second leading cause of cancer deaths worldwide, thereby necessitating an accurate and cost-effective solution for managing care. Ultrasound is well poised to address this need due to its low cost, portability, safety, and excellent temporal resolution. The role of ultrasound for HCC screening has been well established and supported by multiple international guidelines. Similarly, contrast-enhanced ultrasound (CEUS) can be used for the characterization of focal liver lesions in high-risk populations, and standardized criteria for CEUS have been established by the American College of Radiology Liver Imaging Reporting & Data System (LI-RADS). Following HCC identification, CEUS can also be highly beneficial in treatment planning, delivery, and monitoring HCC response to locoregional therapies. Specific advantages of CEUS include providing real-time treatment guidance and improved diagnostic performance for the detection of residual tumor viability or recurrence, thereby identifying patients in need of retreatment substantially earlier than contrast-enhanced CT and MRI. This review provides a primer on ultrasound and CEUS for the screening and characterization of HCC, with an emphasis on assessing tumor response to locoregional therapies.

Biochemical Safety of Ablative Yttrium-90 Radioembolization for Hepatocellular Carcinoma as a Function of Percent Liver Treated

Purpose

Transarterial radioembolization can serve as an ablative therapy for early-stage hepatocellular carcinoma (HCC). Given the volumetric variability of liver segments, this study aimed to characterize the safety of ablative radioembolization by determining percent liver treated (%LT) thresholds associated with biochemical toxicity.

Patients and Methods

Patients with HCC receiving a single ablative radioembolization treatment using glass microspheres from 2017 through 2020 were reviewed. %LT was calculated as treatment angiosome volume divided by whole liver volume. Biochemical toxicities were defined as increases in Albumin-Bilirubin (ALBI) grade or Child-Pugh (CP) class compared to baseline and albumin or bilirubin adverse events (AEs) per the Common Terminology Criteria for Adverse Events. Receiver operating characteristic curves and multivariate logistic regression analyses were performed to assess the impact of %LT on toxicities.

Results

Of 141 patients analyzed, 53% (n=75) were ALBI 1, 45% (n=64) ALBI 2, 79% (n=111) CP-A, and 21% (n=30) CP-B. A %LT ≥14.5% was associated with grade/class increases in ALBI 2 (p≤0.01) and CP-B patients (p=0.026). In multivariate analysis, a %LT ≥14.5% was an independent predictor of increases in the ALBI 2 and CP-B groups (p<0.01). No significant %LT threshold was found for ALBI 1 and CP-A patients. No grade 3/4 albumin or bilirubin AEs were reported, while grade 2 AEs were related to an initial whole liver volume <1.3 L (p≤0.01).

Conclusion

Patients with ALBI 2 and CP-B liver function are less likely to have an increase in their respective grade/class when treating <14.5% of the liver using glass microspheres. ALBI 1 and CP-A patients showed no definitive %LT threshold for biochemical toxicity within the range of this study.

Predictors of Successful Yttrium-90 Radioembolization Bridging or Downstaging in Patients with Hepatocellular Carcinoma

PURPOSE

This study aims to identify clinical and imaging prognosticators associated with the successful bridging or downstaging to liver transplantation (LT) in patients undergoing Yttrium-90 radioembolization (Y90-RE) for hepatocellular carcinoma (HCC).

METHODS

Retrospectively, patients with Y90-RE naïve HCC who were candidates or potential candidates for LT and underwent Y90-RE were included. Patients were then divided into favorable (maintained or achieved Milan criteria (MC) eligibility) or unfavorable (lost eligibility or unchanged MC ineligibility) cohorts based on changes to their MC eligibility after Y90-RE. Penalized logistic regression analysis was performed to identify the significant baseline prognosticators.

RESULTS

Between 2013 and 2018, 135 patients underwent Y90-RE treatment. Among the 59 (42%) patients within MC, LT eligibility was maintained in 49 (83%) and lost in 10 (17%) patients. Within the 76 (56%) patients outside MC, eligibility was achieved in 32 (42%) and unchanged in 44 (58%). Among the 81 (60%) patients with a favorable response, 16 (20%) went on to receive LT. Analysis of the baseline characteristics revealed that lower Albumin-Bilirubin score, lower Child-Pugh class, lower Barcelona Clinic Liver Cancer stage, HCC diagnosis using dynamic contrast-enhanced imaging on CT or MRI, normal/higher albumin levels, decreased severity of tumor burden, left lobe HCC disease, and absence of HBV-associated cirrhosis, baseline abdominal pain, or fatigue were all associated with a higher likelihood of bridging or downstaging to LT eligibility (p's < 0.05).

CONCLUSION

Certain baseline clinical and tumor characteristics are associated with the successful bridging or downstaging of potential LT candidates with HCC undergoing Y90-RE.