Potential and Clinical Significance of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for Evaluating Liver Cancer Response to Lenvatinib Treatment

The application of 18F-FDG PET/CT imaging for human hepatocellular carcinoma: a narrative review

Background and Objective

Primary hepatocellular carcinoma (HCC) poses a significant threat to human health. The mean overall survival (OS) of HCC is approximately 15.8 months whereas the 6-month and 1-year OS rates are only 71.6% and 49.7%, respectively. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) has been widely used for the management of several solid cancers; however, HCC frequently displays low 18F-FDG uptake; approximately 50% of HCC cases do not take up 18F-FDG. Therefore, 18F-FDG PET is not considered very useful for the visualization of HCC and is not currently a recommended standard imaging modality for HCC. Conversely, 18F-FDG PET/CT has been reported to be clinically important in the management, staging, and prognosis of HCC patients. Currently, reports relating to 18F-FDG uptake in HCC are unclear and controversial. There is an urgent need to clarify the efficacy of 18F-FDG PET for the management of HCC.

Methods

The PubMed database was searched for all articles on the application of 18F-FDG PET/CT imaging for human HCC up to December 2021. The following search terms were used: 'Hepatocellular carcinoma', '[18F]FDG PET/CT', 'Hypoxia', '[11C]Choline'.

Key Content and Findings

In this review, we re-evaluate the potential hypoxia-dependent uptake mechanism of 18F-FDG in HCC and review the usefulness of 18F-FDG PET/CT for identifying, managing, and investigating the biological properties of HCC.

Conclusions

18F-FDG PET/CT is very useful for HCC visualization, management, and the evaluation of biological properties. A negative test for 18F-FDG uptake is not meaningless and may reflect a relatively better outcome. 18F-FDG-positive lesions indicate a significantly less favorable prognosis.

Metabolic Tumor Volume Measured by 18F-FDG PET/CT is Associated with the Survival of Unresectable Hepatocellular Carcinoma Treated with PD-1/PD-L1 Inhibitors Plus Molecular Targeted Agents

Purpose

The combination of PD-1/PD-L1 inhibitors and molecular targeted agents showed promising efficacy for unresectable hepatocellular carcinoma (uHCC). This study aimed to investigate the prognostic value of metabolic parameters from ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET/CT) in patients with uHCC underwent the combined therapies.

Patients and Methods

Patients with uHCC treated with a combination of immunotherapy and targeted therapy who underwent baseline ¹⁸F-FDG PET/CT between July 2018 and December 2021 were recruited retrospectively. The metabolic tumor volume (MTV), total lesion glycolysis (TLG), maximum standardized uptake values (SUV_max), and clinical and biological parameters were recorded. A multivariate prediction model was developed for overall survival (OS) using these parameters together with clinical prognostic factors.

Results

Seventy-seven patients were finally included. The median OS was 16.8 months. We found that a high MTV (≥39.65 cm³ as the median value) was significantly associated with OS (P<0.05). In multivariate analyses for OS, a high MTV, high Eastern Cooperative Oncology Group performance status (ECOG-PS, ≥1), Child-Pugh (B-C) grade, and the presence of bone metastasis were significantly associated with poor OS (HR 1.371, HR 3.73, HR 15.384, and HR 2.994, all P<0.05, respectively). A multivariate prognostic model including MTV and prognostic factors, such as ECOG-PS, Child-Pugh grade, and bone metastasis, further improved the identification of different OS subgroups.

Conclusion

High MTV is an adverse prognostic factor in patients with uHCC treated with a combination of immunotherapy and molecular targeted agents. Integrating PET/CT parameters with clinical prognostic factors could help to personalize immunotherapy.

RECIST 1.1 versus mRECIST for assessment of tumour response to molecular targeted therapies and disease outcomes in patients with hepatocellular carcinoma: a systematic review and meta-analysis

OBJECTIVES

Response Evaluation Criteria in Solid Tumours version 1.1 (RECIST 1.1) and modified RECIST (mRECIST) are commonly used to assess tumour response. Which one is better to evaluate efficacy after molecular targeted therapies in hepatocellular carcinoma (HCC) patients is still controversial. A systemic review was performed to compare the objective response rate (ORR) and disease control rate (DCR) and a meta-analysis was conducted to compare the correlation between objective response and overall survival (OS).

DESIGN

Systematic review and meta-analysis using the Grading of Recommendations Assessment, Development and Evaluation approach.

DATA SOURCES

EMBASE, PubMed, Web of Science and Cochrane Library were searched through 31 December 2021.

ELIGIBILITY CRITERIA

We included studies assessing the efficacy of molecular targeted therapy for HCC according to both RECIST 1.1 and mRECIST.

DATA EXTRACTION AND SYNTHESIS

Two investigators extracted data independently. The consistency between RECIST 1.1 vs mRECIST is measured by the k coefficient. HRs with corresponding 95% CIs were used for meta-analysis.

RESULTS

23 studies comprising 2574 patients were included in systematic review. The ORR according to mRECIST is higher than RECIST1.1 (15.9% vs 7.8%, p<0.001). The DCR is similar (68.4% vs 67.2%, p=0.5). The agreement of tumour response is moderate for objective response (k=0.499) and perfect for progressive disease (k=0.901), calculated from 8 studies including 372 patients. OS was significantly longer in response group than non-response group according to mRECIST (HR 0.56, 95% CI 0.41 to 0.78, p=0.0004) calculated from 7 studies including 566 patients, however, the RECIST1.1 could not distinguish the OS well (HR 0.68, 95% CI 0.44 to 1.05, p=0.08). Subgroup analusis by type of treatment was conducted.

CONCLUSIONS

mRECIST may be more accurate than RECIST 1.1 in assessing ORR after molecular targeted therapies in HCC patients and can better assess the prognosis. However, the performance of both criteria in assessing disease progression is identical.

PROSPERO REGISTRATION NUMBER

CRD42020200895.

ETHICS APPROVAL

Ethics approval is not required in this meta-analysis.

Changes in the Mean Intrahepatic Target Computed Tomography Attenuation Value During Treatment May Be a Useful New Predictor of the Post-progression Survival Associated with Lenvatinib Treatment

Objective The relationship between the prognosis and magnitude of a decrease in tumor blood flow according to estimated tumor differentiation remains unclear. This study investigated the relationship between reductions in the rate of mean computed tomography (CT) attenuation values and the clinical prognosis. Methods We evaluated 63 consecutive patients who received lenvatinib treatment for unresectable hepatocellular carcinoma (HCC). The oncological aggressiveness of the tumors was estimated using classification by dynamic CT enhancement patterns. The utility of changes in mean CT attenuation values of intra-hepatic targets during treatment to estimate the prognosis was investigated by calculating the progression-free survival (PFS) and post-progression survival (PPS). A multivariate analysis was used to identify potential confounders for the survival after progression during lenvatinib therapy. Results The rate of decrease in the mean CT attenuation value gradually increased according to the degree of deterioration in estimated tumor differentiation, and the rate of a decrease in attenuation ≥40% showed a tendency to increase (p=0.064). This trend was reflected by a better objective response in oncological aggressiveness heterogeneous enhancement patterns (Type-3 and Type-4) than a homogeneous enhancement pattern (Type-2) (83% vs. 56% of modified Response Evaluation Criteria in Solid Tumors). This resulted in a similar PFS between the groups (p=0.773), whereas the PPS was significantly worse when the rate of decrease in the attenuation value was ≥40% (p=0.012). A multivariate analysis confirmed that a rate of decease in attenuation value ≥40% was a poor prognostic factor for the PPS (hazard ratio, 2.993; 95% confidence interval, 1.196-7.490; p=0.019). Conclusion A rate of decrease in attenuation ≥40% may reflect a good response of a highly malignant tumor to lenvatinib. Therefore, this value may have utility as a surrogate marker for estimating the oncological aggressiveness of tumors and their associated prognosis.

Variability in biopsy quality informs translational research applications in hepatocellular carcinoma

In the era of precision medicine, biopsies are playing an increasingly central role in cancer research and treatment paradigms; however, patient outcomes and analyses of biopsy quality, as well as impact on downstream clinical and research applications, remain underreported. Herein, we report biopsy safety and quality outcomes for percutaneous core biopsies of hepatocellular carcinoma (HCC) performed as part of a prospective clinical trial. Patients with a clinical diagnosis of HCC were enrolled in a prospective cohort study for the genetic, proteomic, and metabolomic profiling of HCC at two academic medical centers from April 2016 to July 2020. Under image guidance, 18G core biopsies were obtained using coaxial technique at the time of locoregional therapy. The primary outcome was biopsy quality, defined as tumor fraction in the core biopsy. 56 HCC lesions from 50 patients underwent 60 biopsy events with a median of 8 core biopsies per procedure (interquartile range, IQR, 7–10). Malignancy was identified in 45/56 (80.4%, 4 without pathology) biopsy events, including HCC (40/56, 71.4%) and cholangiocarcinoma (CCA) or combined HCC-CCA (5/56, 8.9%). Biopsy quality was highly variable with a median of 40% tumor in each biopsy core (IQR 10–75). Only 43/56 (76.8%) and 23/56 (41.1%) samples met quality thresholds for genomic or metabolomic/proteomic profiling, respectively, requiring expansion of the clinical trial. Overall and major complication rates were 5/60 (8.3%) and 3/60 (5.0%), respectively. Despite uniform biopsy protocol, biopsy quality varied widely with up to 59% of samples to be inadequate for intended purpose. This finding has important consequences for clinical trial design and highlights the need for quality control prior to applications in which the presence of benign cell types may substantially alter findings.

A case of conversion hepatectomy for huge ruptured hepatocellular carcinoma after transarterial embolization and lenvatinib therapy

We herein report a successfully treated case of huge ruptured hepatocellular carcinoma (HCC) by conversion hepatectomy after transarterial embolization (TAE) and lenvatinib therapy. A 33-year-old male patient with right hypochondralgia and liver tumor was referred to our hospital. He had a history of surgery for heart malformation. The tumor at the right lobe was 15 cm in diameter with bloody ascites. Right atrial thrombus 4.5 cm in diameter and marked cardiac dilatation were observed. TAE with ethanol suspended in lipiodol and gelatin sponge achieved hemostasis of the ruptured HCC. Although viable HCC remained after TAE, surgical treatment was abandoned because of abdominal wall invasion and his heart function. Lenvatinib and rivaroxaban were then initiated for HCC and atrial thrombus, respectively. Lenvatinib treatment resulted in a reduction in tumor marker levels and the tumor size. First, we planned conversion hepatectomy after 5 months of lenvatinib. However, recurrence of atrial thrombus prompted us to put off the surgery, and lenvatinib was re-administered. After improvement of atrial thrombus, we finally performed conversion hepatectomy 10 months after starting lenvatinib administration. The tumor was completely removed by combined resection of the diaphragm, and the patient has been doing well without any signs of recurrence.