Prediction of overall survival in patients with hepatocellular carcinoma treated with Y-90 radioembolization by imaging response criteria

The role of biomarkers and dosimetry parameters in overall and progression free survival prediction for patients treated with personalized 90Y glass microspheres SIRT: a preliminary machine learning study

BACKGROUND

Overall Survival (OS) and Progression-Free Survival (PFS) analyses are crucial metrics for evaluating the efficacy and impact of treatment. This study evaluated the role of clinical biomarkers and dosimetry parameters on survival outcomes of patients undergoing 90Y selective internal radiation therapy (SIRT).

MATERIALS/METHODS

This preliminary and retrospective analysis included 17 patients with hepatocellular carcinoma (HCC) treated with 90Y SIRT. The patients underwent personalized treatment planning and voxel-wise dosimetry. After the procedure, the OS and PFS were evaluated. Three structures were delineated including tumoral liver (TL), normal perfused liver (NPL), and whole normal liver (WNL). 289 dose-volume constraints (DVCs) were extracted from dose-volume histograms of physical and biological effective dose (BED) maps calculated on 99mTc-MAA and 90Y SPECT/CT images. Subsequently, the DVCs and 16 clinical biomarkers were used as features for univariate and multivariate analysis. Cox proportional hazard ratio (HR) was employed for univariate analysis. HR and the concordance index (C-Index) were calculated for each feature. Using eight different strategies, a cross-combination of various models and feature selection (FS) methods was applied for multivariate analysis. The performance of each model was assessed using an averaged C-Index on a three-fold nested cross-validation framework. The Kaplan-Meier (KM) curve was employed for univariate and machine learning (ML) model performance assessment.

RESULTS

The median OS was 11 months [95% CI: 8.5, 13.09], whereas the PFS was seven months [95% CI: 5.6, 10.98]. Univariate analysis demonstrated the presence of Ascites (HR: 9.2[1.8,47]) and the aim of SIRT (segmentectomy, lobectomy, palliative) (HR: 0.066 [0.0057, 0.78]), Aspartate aminotransferase (AST) level (HR:0.1 [0.012-0.86]), and MAA-Dose-V205(%)-TL (HR:8.5[1,72]) as predictors for OS. 90Y-derived parameters were associated with PFS but not with OS. MAA-Dose-V205(%)-WNL, MAA-BED-V400(%)-WNL with (HR:13 [1.5-120]) and 90Y-Dose-mean-TL, 90Y-D50-TL-Gy, 90Y-Dose-V205(%)-TL, 90Y-Dose- D50-TL-Gy, and 90Y-BED-V400(%)-TL (HR:15 [1.8-120]) were highly associated with PFS among dosimetry parameters. The highest C-index observed in multivariate analysis using ML was 0.94 ± 0.13 obtained from Variable Hunting-variable-importance (VH.VIMP) FS and Cox Proportional Hazard model predicting OS, using clinical features. However, the combination of VH. VIMP FS method with a Generalized Linear Model Network model predicting OS using Therapy strategy features outperformed the other models in terms of both C-index and stratification of KM curves (C-Index: 0.93 ± 0.14 and log-rank p-value of 0.023 for KM curve stratification).

CONCLUSION

This preliminary study confirmed the role played by baseline clinical biomarkers and dosimetry parameters in predicting the treatment outcome, paving the way for the establishment of a dose-effect relationship. In addition, the feasibility of using ML along with these features was demonstrated as a helpful tool in the clinical management of patients, both prior to and following 90Y-SIRT.

Selective internal radiation therapy for unresectable HCC: The SIRT downstaging study

BACKGROUND

Selective internal radiation therapy (SIRT) is recommended as a downstaging (DS) strategy for solitary unresectable HCC <8 cm. The aim of this study was to report the results of acquired experience in a tertiary center for all unresectable HCCs.

METHODS

We conducted a retrospective, observational study using data collected from consecutive patients undergoing SIRT between October 2013 and June 2020. DS was considered achieved when a curative treatment could be proposed 6 months after SIRT.

RESULTS

One hundred twenty-seven patients were included (male = 90%, 64 ± 11 y), of whom 112 (n = 88%) had cirrhosis. HCC was classified as BCLC stage C in 64 patients (50%), with a median diameter of 61 mm, an infiltrative pattern in 51 patients (40%), and portal vein invasion in 62 (49%) patients. Fifty patients (39%) achieved DS 6 months following SIRT, with 29 of them (23%) undergoing curative treatment in a median time of 4.3 months: 17 (13%) were transplanted, 11 (85%) had liver resection, and 1 patient had a radiofrequency ablation. The median overall survival of patients with or without DS was 51 versus 10 months, respectively (p < 0.001). In patients who achieved DS, progression-free survival was higher in patients who underwent surgery: 47 versus 11 months (p < 0.001). Four variables were independently associated with DS: age (OR: 0.96, 95% CI: [0.92, 0.99]; p = 0.032), baseline α-fetoprotein (OR: 1.00, 95% CI: [1.00, 1.00]; p = 0.034), HCC distribution (OR: 0.3, 95% CI: [0.11, 0.75]; p = 0.012), and ALBI grade (OR: 0.34. 95% CI: [0.14, 0.80]; p = 0.014).

CONCLUSIONS

These results suggest that SIRT in patients with unresectable HCC could be an effective treatment: DS was achieved for around 39% of the patients and more than half of these then underwent curative treatment.

Local recurrence following a complete radiologic response in hepatocellular carcinoma patients: comparison of transarterial chemoembolisation and transarterial radioembolisation

AIM

To evaluate and compare the rates of local recurrence in hepatocellular carcinoma (HCC) patients who undergo selective transarterial radioembolisation (TARE) or transarterial chemoembolisation (TACE) and achieve a complete response (CR) radiologically.

MATERIALS AND METHODS

All patients undergoing treatment with TARE or TACE at a single academic institution were reviewed retrospectively. Those who had been treated previously, presented with multifocal disease, had non-selective TARE or TACE, or did not achieve a complete response (CR) radiologically were excluded.

RESULTS

In total 110 patients were included (TACE n=60 [54.5%]; TARE n=50 [45.5%]). TARE patients were older (66.4 ± 9.4 versus 61.2 ± 5.6 years, p<0.001) and had larger tumours (4.4 ± 2.2 versus 3 ± 1.4 cm, p=0.002). TACE patients were significantly more likely to suffer a local recurrence (31/60, 51.7% versus 9/50, 18%, p<0.001) and had a significantly shorter time to recurrence (median 8.3 {interquartile range [IQR]}: 12 versus median 17.9 [IQR: 23.5] months, p=0.001). A local time to progression (TTP) Kaplan-Meier curve demonstrated TACE patients had a significantly shorter local TTP (hazard ratio [HR]: 7.2; 95% confidence interval [CI]: 3.64-14.24; p<0.001) and treatment modality (TACE or TARE; HR: 0.05; 95% CI: 0.005-0.5; p=0.01) was found to be associated with local recurrences on multivariate Cox proportional HR analysis. When overall TTP was evaluated, again TACE patients were found to have a significantly shorter TTP (HR: 2.13 [1.28-3.53], p=0.004).

CONCLUSION

In HCC patients undergoing selective treatment who achieve a CR radiologically, those treated with TARE may be less likely to suffer recurrence, either local or general, than those treated with TACE.

Stage migration as a surrogate of survival in hepatocellular carcinoma treated with transarterial chemoembolization

BACKGROUND AIMS

Locoregional therapies, including transarterial chemoembolization (TACE), are recommended for the treatment of HCC; however, clinical trials evaluating their effectiveness have been complicated by a lack of validated surrogate outcomes. We aimed to evaluate if stage migration could serve as a potential surrogate of overall survival in patients undergoing TACE.

APPROACH

We conducted a retrospective cohort study of adult patients with HCC who underwent TACE as initial therapy from 3 centers in the US from 2008 to 2019. The primary outcome was overall survival from the date of the first TACE treatment, and the primary exposure of interest was Barcelona Clinic Liver Cancer stage migration to a more advanced stage within 6 months of TACE. Survival analysis was completed using Kaplan-Meier and multiple Cox proportional hazard models adjusted by the site.

RESULTS

Of 651 eligible patients (51.9% Barcelona Clinic Liver Cancer stage A and 39.6% stage B), 129 (19.6%) patients experienced stage migration within 6 months of TACE. Those with stage migration had larger tumors (5.6 vs. 4.2 cm, p < 0.01) and higher AFP levels (median 92 vs. 15 ng/mL, p < 0.01). In multivariate analysis, stage migration was significantly associated with worse survival (HR: 2.82, 95% CI: 2.66-2.98), with a median survival of 8.7 and 15.9 months in those with and without stage migration. Other predictors of worse survival included the White race, higher AFP levels, a higher number of tumors, and a larger maximum HCC diameter.

CONCLUSION

Stage migration is associated with increased mortality after TACE in patients with HCC and could serve as a surrogate end point in clinical trials evaluating locoregional therapies such as TACE.

Lung shunt fraction calculations before Y-90 transarterial radioembolization: Comparison of accuracy and clinical significance of planar scintigraphy and SPECT/CT

PURPOSE

To determine the accuracy and clinical significance of planar scintigraphy lung shunt fraction (PLSF) and single-photon emission computerized tomography (SPECT) computed tomography (CT) lung shunt fraction (SLSF) before Y-90 transarterial radioembolization.

MATERIALS AND METHODS

Seventy patients (46 men, 24 women; mean age, 64 ± 9.5 [SD] years) who underwent 83 treatments with Y-90 transarterial radioembolization for primary or secondary malignancies of the liver with a PLSF ≥ 7.5% were retrospectively evaluated. The patients mapping technetium 99 m (Tc-99 m) macroaggregated albumin (MAA) PLSF and SLSF were calculated and compared to the post Y-90 delivery SLSF. A model using modern dose thresholds was created to identify patients who would require dose reduction due to a lung dose ≥ 30 Gy, with patients who required >50% dose reduction considered to be delivery cancelations.

RESULTS

A significant difference was found between mean PLSF (14.7 ± 11.6 [SD]%; range: 7.5-84.1%) and mean SLSF (8.7 ± 8.5 [SD]%; range: 1.7-73.5) (P < 0.001). The mean realized LSF (7.1 ± 3 [SD]%; range:1.5-17.6) was significantly less than the PLSF (P <0.001) but not the SLSF (P = 0.07). PLSF significantly overestimated the realized LSF by more than the SLSF (8.5 ± 5.3 [SD] % [range: -0.1-21.7] vs. 0.8 ± 3.6 [SD] % [range: -5-13.2], respectively) (P < 0.001). Based on the clinical significance model, 20 patients (20/83, 24.1%) would have required dose reduction or cancelation when using PLSF but would not require even a dose reduction when using the SLSF. Significantly more deliveries would have been be canceled if PLSF was used as compared to SLSF (22/83 [26.5%] vs. 6/83 [7.2%], respectively) (P < 0.001).

CONCLUSION

SLSF is significantly more accurate at predicting realized LSF than PLSF and this difference is of clinical significance in a number of patients with a PLSF ≥ 7.5%.

Therapeutic Management of Advanced Hepatocellular Carcinoma: An Updated Review

Hepatocellular carcinoma (HCC) usually occurs in the setting of liver cirrhosis and more rarely in a healthy liver. Its incidence has increased in the past years, especially in western countries with the rising prevalence of non-alcoholic fatty liver disease. The prognosis of advanced HCC is low. In the first-line setting of advanced HCC, sorafenib, a tyrosine kinase inhibitor, was the only validated treatment for many years. In 2020, the combination of atezolizumab, an immune checkpoint inhibitor, and bevacizumab showed superiority to sorafenib alone in survival, making it the first-line recommended treatment. Regorafenib and lenvatinib, other multikinase inhibitors, were also validated in the second and first-line settings, respectively. Transarterial chemoembolization can be an alternative treatment for patients with intermediate-stage HCC and preserved liver function, including unresectable multinodular HCC without extrahepatic spread. The current challenge in advanced HCC lies in the selection of a patient for the optimal treatment, taking into account the underlying liver disease and liver function. Indeed, all trial patients present with a Child-Pugh score of A, and the optimal approach for other patients is still unclear. Furthermore, the combination of atezolizumab and bevacizumab should be considered in the absence of medical contraindication. Many trials testing immune checkpoint inhibitors in association with anti-angiogenic agents are ongoing, and primary results are promising. The landscape in advanced HCC management is undergoing profound change, and many challenges remain for optimal patient management in the years to come. This review aimed to provide an overview of current systemic treatment options for patients with advanced unresectable HCC who are not candidates for liver-directed therapy.

90Y Radioembolization versus Drug-eluting Bead Chemoembolization for Unresectable Hepatocellular Carcinoma: Results from the TRACE Phase II Randomized Controlled Trial

Background Transarterial chemoembolization (TACE) is the recommended treatment for intermediate hepatocellular carcinoma (HCC) according to the Barcelona Clinic Liver Cancer guidelines. Prospective uncontrolled studies suggest that yttrium 90 (⁹⁰Y) transarterial radioembolization (TARE) is a safe and effective alternative. Purpose To compare the efficacy and safety of TARE with TACE for unresectable HCC. Materials and Methods In this single-center prospective randomized controlled trial (TRACE), ⁹⁰Y glass TARE was compared with doxorubicin drug-eluting bead (DEB) TACE in participants with intermediate-stage HCC, extended to Eastern Cooperative Oncology Group performance status 1 and those with early-stage HCC not eligible for surgery or thermoablation. Participants were recruited between September 2011 and March 2018. The primary end point was time to overall tumor progression (TTP) (Kaplan-Meier analysis) in the intention-to-treat (ITT) and per-protocol (PP) groups. Results At interim analysis, 38 participants (median age, 67 years; IQR, 63-72 years; 33 men) were randomized to the TARE arm and 34 (median age, 68 years; IQR, 61-71 years; 30 men) to the DEB-TACE arm (ITT group). Median TTP was 17.1 months in the TARE arm versus 9.5 months in the DEB-TACE arm (ITT group hazard ratio [HR], 0.36; 95% CI: 0.18, 0.70; P = .002) (PP group, 32 and 34 participants, respectively, in each arm; HR, 0.29; 95% CI: 0.14, 0.60; P < .001). Median overall survival was 30.2 months after TARE and 15.6 months after DEB-TACE (ITT group HR, 0.48; 95% CI: 0.28, 0.82; P = .006). Serious adverse events grade 3 or higher (13 of 33 participants [39%] vs 19 of 36 [53%] after TARE and DEB-TACE, respectively; P = .47) and 30-day mortality (0 of 33 participants [0%] vs three of 36 [8.3%]; P = .24) were similar in the safety groups. At the interim, the HR for the primary end point, TTP, was less than 0.39, meeting the criteria to halt the study. Conclusion With similar safety profile, yttrium 90 radioembolization conferred superior tumor control and survival compared with chemoembolization using drug-eluting beads in selected participants with early or intermediate hepatocellular carcinoma. Clinical trial registration no. NCT01381211 © RSNA, 2022 Online supplemental material is available for this article.

Quantitative and qualitative evaluation of liver metastases with intraprocedural cone beam CT prior to transarterial radioembolization as a predictor of treatment response

Purpose

To investigate, by quantitative and qualitative enhancement measurements, the correlation between tumor enhancement on cone beam computed tomography (CBCT) images and treatment response at 6 months in patients undergoing transarterial radioembolization (TARE) for liver metastases.

Materials and Methods

36 patients (56% male; median age 62.5 years) with 104 metastases were retrospectively included. Quantitative and qualitative enhancement of liver metastases were evaluated on CBCT images before TARE. Quantitative analysis consisted of lesion enhancement measurements (ROI HU lesion - ROI HU relative to inferior vena cava). Qualitative analysis consisted of subjective enhancement pattern analysis (diffuse, sparse, rim-like or non-enhancing). Morphologic tumor response was evaluated according to RECIST 1.1 criteria on follow-up CT or MR imaging.

Results

At a mean follow up of 6.5 ± 3.7 months, progressive disease (PD) was found in 4 patients, partial response (PR) in 11 and stable disease (SD) in 21. Relative lesion enhancement was significantly different between these groups (-37.5±154.2 HU vs. 103.8±93.4 vs. 181±144 HU in PD vs. SD vs. PR group, respectively; p<0.01). ROC analysis of relative lesion enhancement to predict progressive disease showed an area under the curve of 0.86 (p<0.01). For qualitative lesion enhancement analysis, no difference between groups was found.

Conclusion

Quantitative enhancement measurements derived from intraprocedural contrast enhanced CBCT may identify responders to TARE in patients with liver metastases.

Local recurrence following complete radiologic response in patients treated with transarterial chemoembolization for hepatocellular carcinoma

PURPOSE

The purpose of this study was to determine the local progression rate and identify factors that may predict local progression, in patients who achieve a complete response (CR) radiologically after undergoing transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

One-hundred-forty-seven patients, who achieved CR of 224 HCCs after TACE, were retrospectively reviewed. There were 109 men and 38 women with a mean age of 61.6 ± 6.8 (SD) years (range: 45.4-86.9 years). Logistic mixed-effects and Cox regression models were used to evaluate associations between clinical factors and local progression.

RESULTS

A total of 75 patients (75/147; 51%) and 99 (99/224,44.2%) lesions showed local progression at a median of 289.5 days (Q1: 125, Q3: 452; range: 51-2245 days). Pre-treatment, international normalization ratio (INR) (1.17 ± 0.15 [SD] vs. 1.25 ± 0.16 [SD]; P <0.001), model for end-stage liver disease (9.4 ± 2.6 [SD] vs. 10.6 ± 3.2 [SD]; P = 0.010) and Child-Pugh score (6 ± 1 [SD] vs. 6.4 ± 1.3 [SD]; P = 0.012) were significantly lower while albumin serum level (3.4 ± 0.62 [SD] vs. 3.22 ± 0.52 [SD]; P = 0.033) was significantly greater in those who showed local progression as compared to those who did not. In terms of local-recurrence free survival, the number of TACE treatments (hazard ratio [HR]: 2.05 [95% CI: 1.57-2.67]; P<0.001), INR (HR: 0.13 [95% CI: 0.03-0.61]; P = 0.010) and type of TACE (P = 0.003) were significant. Patients with local progression on any tumor did not differ from those who did in terms of overall survival (P = 0.072), however, were less likely to be transplanted (20/75, 26.7%) than those who did not (33/72; 36.1%) (P = 0.016).

CONCLUSION

A significant number of patients who achieve CR of HCC after TACE have local progression. This emphasizes the importance of long-term follow up.

Role of Resin Microsphere Y90 Dosimetry in Predicting Objective Tumor Response, Survival and Treatment Related Toxicity in Surgically Unresectable Colorectal Liver Metastasis: A Retrospective Single Institution Study

Simple Summary

Colorectal liver metastases are difficult to treat, with only a minority of patients eligible for surgical resection. Yttrium-90 selective internal radiation therapy is an alternative treatment currently used for patients who have progressed on chemotherapy. A technique called dosimetry allows clinicians to analyze how much radiation was delivered to target lesions post-treatment. The aim of this study is to evaluate the relationship of various dosimetric parameters with objective tumor response, overall survival, and treatment related toxicity with the potential goal of optimizing Yttrium-90 treatment in this patient population. Additionally, other potential predictors of survival outcomes, including clinical and demographic factors, were also evaluated. We found that delivering a mean tumor dose ≥100 Gy when using resin microspheres was significantly associated with objective tumor response and prolonged overall survival. In this study, no mean non-tumoral liver dose threshold was found to predict treatment related toxicity.

Abstract

Purpose: To Evaluate the correlation between tumor dosimetric parameters with objective tumor response (OR) and overall survival (OS) in patients with surgically unresectable colorectal liver metastasis (CRLM) undergoing resin-based Ytrrium-90 selective internal radiation therapy (Y90 SIRT). Materials and Methods: 45 consecutive patients with CRLM underwent resin-based Y90 SIRT in one or both hepatic lobes (66 treated lobes total). Dose volume histograms were created with MIM Sureplan^® v.6.9 using post-treatment SPECT/CT. Dosimetry analyses were based on the cumulative volume of the five largest tumors in each treatment session and non-tumoral liver (NTL) dose. Receiver operating characteristic (ROC) curve was used to evaluate tumor dosimetric factors in predicting OR by Response Evaluation Criteria for Solid Tumors at 3 months post-Y90. Additionally, ROC curve was used to evaluate non-tumoral liver dose as a predictor of grade ≥ 3 liver toxicity and radioembolization induced liver disease (REILD) 3 months post Y90. To minimize for potential confounding demographic and clinical factors, univariate and multivariate analysis of survival with mean tumor dose as one of the factors were also performed. Kaplan-Meier estimation was used for OS analysis from initial Y90 SIRT. Results: 26 out of 45 patients had OR with a median OS of 17.2 months versus 6.8 months for patients without OR (p < 0.001). Mean tumor dose (TD) of the five largest tumors was the strongest predictor of OR with an area under the curve of 0.73 (p < 0.001). Minimum TD, and TD to 30%, 50%, and 70% of tumor volume also predicted OR (p’s < 0.05). Mean TD ≥ 100 Gy predicted a significantly prolonged median OS of 19 vs. 11 months for those receiving TD < 100 Gy (p = 0.016). On univariate analysis, mean TD < 100 Gy, presence of any genomic mutation, presence of MAPK pathway mutation, bilobar hepatic metastases and diffuse metastatic disease (>10 lesions per liver lobe) were found to be predictors of shorter median OS. On multivariate analysis, mean TD < 100 Gy, presence of any genomic mutation, and diffuse hepatic metastatic disease were found to be independent predictors of shorter OS. Overall, six (13.3%) patients developed grade ≥ 3 liver toxicity post Y90 of whom two (4.4%) patients developed REILD. No dose threshold predicting grade ≥ 3 liver toxicity or REILD was identified. Conclusions: Mean TD ≥ 100 Gy in patients with unresectable CRLM undergoing resin-based Y90 SIRT predicts OR and prolonged OS.

Baseline Alpha-Fetoprotein, Alpha-Fetoprotein-L3, and Des-Gamma-Carboxy Prothrombin Biomarker Status in Bridge to Liver Transplant Outcomes for Hepatocellular Carcinoma

Simple Summary

An abnormal alpha-fetoprotein (AFP) test is often associated with hepatocellular carcinoma (HCC) development, although as many as 40% of HCC diagnoses are made in the absence of an abnormal AFP test. In Japan and other Asian countries, Lens culinaris agglutinin-reactive AFP fraction (AFP-L3) and des-gamma-carboxy prothrombin (DCP) are used in combination with AFP for HCC diagnosis. Combined testing with all three biomarkers increases early diagnosis in addition to providing a patient-specific profile of HCC aggressiveness. The utility of AFP, AFP-L3, and DCP for HCC prognosis in the bridge to liver transplantation has not been established. The goal of this study is to define prognosis to first-line HCC treatment and the risk of progression prior to liver transplantation associated with biomarker profile at diagnosis. Biomarker profiling may have future implications in precision therapeutic management of HCC as a bridge to transplantation.

Abstract

The biomarkers α-fetoprotein (AFP), Lens culinaris agglutinin-reactive AFP fraction (AFP-L3), and des-γ-carboxy prothrombin (DCP) have emerging implications in hepatocellular carcinoma (HCC) surveillance, overall prognosis, and post-surgical recurrence risk. This retrospective study investigated treatment and bridge to liver transplant (LT) prognosis associated with AFP, AFP-L3%, and DCP biomarker profiles prior to liver-directed therapy (LDT). In a 140-patient cohort, each biomarker was associated with HCC progression risk using the established thresholds of AFP > 20 ng/mL, AFP-L3 > 15%, and DCP > 7.5 ng/mL. Over 60% of the cohort expressed at least one biomarker at baseline. Although most biomarker-positive patients expressed the clinical standard AFP (57/87), only 32% were positive for AFP alone. Biomarker accumulation increased HCC progression risk but was not associated with demographic factors or preserved liver function. Biomarker triple negative patients had smaller index HCC (p = 0.003), decreased multifocal burden (p = 0.010), and a higher objective response rate (ORR, 62% compared to 46%, p = 0.011). Expressing all three biomarkers at baseline was associated with dismal first-line ORR (12%) with a median time to progression (TTP) of only 181 days post-LDT. Patients with triple negative status for the HCC biomarkers AFP, AFP-L3%, and DCP have the highest first-line ORR with < 5% HCC progression 1-year post-LDT. Biomarker profiling can establish baseline prognosis for identifying optimal bridge to LT and downstaging to LT candidates with triple negative biomarker status and providing an ideal post-LDT target as a compliment to radiographic response.

Utility of Early Posttreatment PET/CT Evaluation Using FDG or 18F-FCH to Predict Response to 90Y Radioembolization in Patients With Hepatocellular Carcinoma

Background: Assessment of hepatocellular carcinoma (HCC) treatment response after transarterial radioembolization (TARE) is challenging, as response by conventional imaging criteria may not become apparent until 6 months after treatment. Though HCC exhibits variability avidity for FDG, some cases of HCC without avidity for FDG show avidity for 18F-FCH. Objectives: To evaluate the utility of early posttreatment evaluation by PET/CT using FDG or 18F-FCH to predict 6-month treatment response and survival after TARE in patients with HCC. Methods: This retrospective study included 37 patients (mean age 67 years; 34 men, 3 women) with documented HCC treated by TARE who underwent both pretreatment FDG PET/CT and 18F-FCH PET/CT, as well as early FDG PET/CT and/or 18F-FCH PET/CT 4-8 weeks after treatment; FDG PET/CT and 18F-FCH PET/CT examinations were performed on separate dates. Only one of 73 initially identified potentially eligible patients was excluded due to lack of HCC avidity for both FDG and 18F-FCH. Response assessment by mRECIST on multiphase CT or MRI was performed at one-month and six-months in 23 patients. Early PET/CT response and one-month mRECIST response were assessed as predictors of six-month mRECIST response. Univariable and multivariable predictors of overall survival (OS) were identified. Results: On pretreatment PET/CT, 28 (76%) patients were FDG-positive, 15 (41%) FCH-positive 6 (16%) both FDG-positive and FCH-positive. Twelve of 28 FDG-positive HCCs exhibited early response by FDG PET/CT; 7 of 15 FCH-positive HCCs exhibited early response by 18F-FCH PET/CT. Twelve (52%) patients exhibited six-month mRECIST response. Early posttreatment PET/CT response exhibited 100% (12/12) sensitivity and 100% (11/11) specificity for six-month mRECIST response, whereas one-month mRECIST response exhibited 67% (8/12) sensitivity and 100% (11/11) specificity for six-month mRECIST response. Early postteatment PET/CT response was a significant independent predictor of OS on univariable (hazard ratio: 0.37, 95% CI: 0.15-0.93, p=.03) and multivariable analyses (hazard ratio: 0.24, 95% CI: 0.08-0.76, p=.01). Conclusion: Early post-TARE evaluation by PET/CT using FDG or 18F-FCH may predict six-month response and OS in patients with HCC. Clinical Impact: Early posttreatment evaluation with PET/CT could help more reliably identify true nonresponders after TARE, which in turn could prompt early adapted therapeutic management.

Treatment response assessment following transarterial radioembolization for hepatocellular carcinoma

Transarterial radioembolization with yttrium-90 microspheres is an established therapy for hepatocellular carcinoma. Post-procedural imaging is important for the assessment of both treatment response and procedural complications. A variety of challenging treatment-specific imaging phenomena complicate imaging assessment, such as changes in tumoral size, tumoral and peritumoral enhancement, and extrahepatic complications. A review of the procedural steps, emerging variations, and timelines for post-treatment tumoral and extra-tumoral imaging changes are presented, which may aid the reporting radiologist in the interpretation of post-procedural imaging. Furthermore, a description of post-procedural complications and their significance is provided.

Reduced nontarget embolization and increased targeted delivery with a reflux-control microcatheter in a swine model

PURPOSE

To evaluate the potential differences in non-target embolization and vessel microsphere filling of a reflux-control microcatheter (RCM) compared to a standard end-hole microcatheter (SEHM) in a swine model.

MATERIALS AND METHODS

Radiopaque microspheres were injected with both RCM and SEHM (2.4-Fr and 2.7-Fr) in the kidneys of a preclinical swine model. Transarterial renal embolization procedures with RCM or SEHM were performed in both kidneys of 14 pigs. Renal arteries were selectively embolized with an automated injection protocol of radio-opaque microspheres. Ex-vivo X-ray microtomography images of the kidneys were utilized to evaluate the embolization by quantification of the deposition of injected microspheres in the target vs. the non-target area of injection. X-ray microtomography images were blindly analyzed by five interventional radiologists. The degree of vessel filling and the non-target embolization were quantified using a scale from 1 to 5 for each parameter. An analysis of variance was used to compare the paired scores.

RESULTS

Total volumes of radio-opaque microspheres injected were similar for RCM (11.5±3.6 [SD] mL; range: 6-17mL) and SEHM (10.6±5.2 [SD] mL; range: 4-19mL) (P=0.38). The voxels enhanced ratio in the target (T) vs. non-target (NT) areas was greater with RCM (T=98.3% vs. NT=1.7%) than with SEHM (T=89% vs. NT=11%) but the difference was not significant (P=0.30). The total score blindly given by the five interventional radiologists was significantly different between RCM (12.3±2.1 [SD]; range: 6-15) and the standard catheter (11.3±2.5 [SD]; range: 4-15) (P=0.0073), with a significant decrease of non-target embolization for RCM (3.8±1.3 [SD]; range: 3.5-4.2) compared to SEHM (3.2±1.5 [SD]; range: 2.9-3.5) (P=0.014).

CONCLUSION

In an animal model, RCM microcatheters reduce the risk of non-target embolization from 11% to 1.7%, increasing the delivery of microspheres of 98% to the target vessels, compared to SEHM microcatheters.

Factors affecting the response to treatment and survival in hepatocellular carcinoma patients treated with transarterial radioembolisation: a single-centre experience

OBJECTIVE

Transarterial radioembolisation (TARE) is a promising technique for unresectable primary tumours of the liver. We present our clinical experience and the response to treatment and survival data of patients with hepatocellular carcinoma (HCC) who were treated with Y-90 radioembolisation in our hospital's angiography department.

MATERIAL AND METHODS

The data of all the patients with HCC referred to our department for Y-90 treatment were analysed retrospectively. The patients were selected according to the treatment protocol criteria, and lung shunt fraction was evaluated using macroaggregated albumin scintigraphy before radioembolisation. Patients with compatible blood tests and lung shunt fraction rates were chosen for treatment with Y-90 TARE.

RESULTS

Twenty-four patients were suitable for Y-90 treatment. The patients were treated with 137 ± 44.6 (80-245) Gy Y-90 glass microspheres. The treatment results were evaluated using modified RECIST criteria, and the partial response, complete response, stable disease and progression rates were found to be 54.2, 16.7, 20.8 and 8.3%, respectively. The median survival rate following treatment was 10 months. Higher alpha-fetoprotein (AFP) levels were related to decreased survival, and posttreatment AFP levels had a significant effect on mortality rates. Higher survival rates were detected in the patients who were treated more selectively than the group treated via a lobar approach.

CONCLUSION

Y-90 microsphere radioembolisation is a safe method and may be helpful in treating patients with unresectable hepatocellular tumours. More favourable results were obtained in the patients treated using the more selective approach. AFP levels before and after treatment could predict survival rates.