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

Prognostic Significance of Volumetric Parameters on Pretreatment FDG PET/CT in Patients With Hepatocellular Carcinoma Receiving Atezolizumab Plus Bevacizumab Therapy

BACKGROUND

This study aimed to assess prognostic significance of FDG PET/CT parameters in predicting progression-free survival (PFS) and overall survival (OS) in patients with hepatocellular carcinoma (HCC) treated with atezolizumab plus bevacizumab therapy.

PATIENTS AND METHODS

We retrospectively enrolled 78 patients with HCC who underwent FDG PET/CT before atezolizumab plus bevacizumab therapy and identified intrahepatic target tumor lesions on pretreatment imaging studies. From PET/CT images, we measured SUVmax, tumor-to-normal liver uptake ratio, metabolic tumor volume, and total lesion glycolysis (TLG) for intrahepatic tumor lesions, as well as SUVmax for extrahepatic metastatic lesions (extrahepatic SUVmax).

RESULTS

In comparisons of PET/CT parameters, patients with progressive disease demonstrated significantly higher TLG values than those achieving complete or partial response ( P < 0.05). In the multivariate survival analysis, TLG independently predicted both PFS ( P = 0.019) and OS ( P = 0.003). Metabolic tumor volume was significantly associated with OS alone ( P = 0.010), and extrahepatic SUVmax was significantly associated with only PFS ( P = 0.045). Patients with high TLG values experienced poorer PFS and OS than those with low TLG values ( P < 0.05).

CONCLUSIONS

TLG in intrahepatic HCC lesions was significantly associated with treatment response and served as an independent prognostic factor for PFS and OS. TLG could be a potential imaging biomarker for predicting clinical outcomes in patients with HCC receiving atezolizumab plus bevacizumab therapy.

Advancements in immunotherapy for hepatocellular carcinoma

INTRODUCTION

The advent of immune-based combinations, primarily leveraging immune checkpoint inhibitors, has revolutionized the therapeutic landscape of hepatocellular carcinoma (HCC). The current scenario features multiple therapies that have shown superiority over tyrosine kinase inhibitors; however, the absence of direct comparisons and validated prognostic biomarkers complicates therapeutic decision-making. Additionally, a significant proportion of patients still exhibit primary or secondary resistance to existing immunotherapies, underscoring the ongoing need for novel therapeutic strategies.

AREAS COVERED

This narrative review discusses current strategies aimed at improving the efficacy of immunotherapy for HCC, focusing on the following aspects: available therapeutic options, identification of prognostic biomarkers, approaches to overcoming resistance (including the development of neoantigen vaccines), and the exploration of adjuvant and neoadjuvant strategies.

EXPERT OPINION

The future of systemic therapies for HCC is likely to be driven by advancements in immunotherapy. Key areas of exploration for the coming years include the discovery of novel checkpoint inhibitors or complementary agents to enhance tumor response when combined with existing treatments, a shift toward neoadjuvant/perioperative trials instead of traditional adjuvant approaches, and the development of personalized neoantigen vaccines.

PET-Assessed Metabolic Tumor Volume Across the Spectrum of Solid-Organ Malignancies: A Review of the Literature

Solid-organ malignancies represent a significant disease burden and remain one of the leading causes of death globally. In the past few decades, the rapid evolution of imaging modalities has shifted the paradigm towards image-based precision medicine, especially in the care of patients with solid-organ malignancies. Metabolic tumor volume (MTV) is one such semi-quantitative parameter obtained from positron emission tomography (PET) imaging with 18F-fluorodeoxyglucose (FDG) that has been shown to have significant implications in the clinical oncology setting. Across various solid tumor malignancies, including lung cancer, head and neck cancer, breast cancer, esophageal cancer, and colorectal cancer, the current literature has demonstrated an association between MTV and various clinical outcomes. MTV may be used in conjunction with several existing and established clinical parameters to help inform risk stratification and treatment strategies and predict outcomes in cancer. Optimizing such volumetric parameters is paramount for advancing efforts to advance cancer care for our patients. While such advancements are made, it is important to investigate and address the limitations of MTV, including variability in terms of measurement methods, a lack of standardized cut-off values, and the impact of inherent tumor heterogeneity. Despite these limitations, which can precipitate challenges in standardization, MTV as a prognostic factor has great potential and opens an avenue for the future integration of technology into an image-based precision medicine model of care for cancer patients. This article serves as a narrative review and explores the utility and limitations of PET-MTV in various settings of solid-organ malignancy.

Cancer Immunotherapy and Medical Imaging Research Trends from 2003 to 2023: A Bibliometric Analysis

Purpose

With the rapid development of immunotherapy, cancer treatment has entered a new phase. Medical imaging, as a primary diagnostic method, is closely related to cancer immunotherapy. However, until now, there has been no systematic bibliometric analysis of the state of this field. Therefore, the main purpose of this article is to clarify the past research trajectory, summarize current research hotspots, reveal dynamic scientific developments, and explore future research directions.

Patients and Methods

A comprehensive search was conducted on the Web of Science Core Collection (WoSCC) database to identify publications related to immunotherapy specifically for the medical imaging of carcinoma. The search spanned the period from the year 2003 to 2023. Several analytical tools were employed. These included CiteSpace (6.2.4), and the Microsoft Office Excel (2016).

Results

By searching the database, a total of 704 English articles published between 2003 and 2023 were obtained. We have observed a rapid increase in the number of publications since 2018. The two most active countries are the United States (n=265) and China (n=170). Pittock, Sean J and Abu-sbeih, Hamzah are very concerned about the relationship between cancer immunotherapy and medical images and have published more academic papers (n = 5; n = 4). Among the top 10 co-cited authors, Topalian Sl (n=43) cited ranked first, followed by Graus F (n=40) cited. According to clustering, timeline, and burst word analysis, the results show that the current research focus is on "MRI", "deep learning", "tumor microenvironment" and so on.

Conclusion

Medical imaging and cancer immunotherapy are hot topics. The United States is the country with the most publications and the greatest influence in this field, followed by China. "MRI", "PET/PET-CT", "deep learning", "immune-related adverse events" and "tumor microenvironment" are currently hot research topics and potential targets.

Biomarkers and prognostic factors of PD-1/PD-L1 inhibitor-based therapy in patients with advanced hepatocellular carcinoma

Systemic therapies using programmed death-1 (PD-1) and programmed death ligand 1 (PD-L1) inhibitors have demonstrated commendable efficacy in some patients with advanced hepatocellular carcinoma (HCC); however, other individuals do not respond favorably. Hence, identifying the biomarkers, the prognostic factors, and their underlying mechanisms is crucial. In this review, we summarized the latest advancements in this field. Within the tumor microenvironment, PD-L1 expression is commonly utilized to predict response. Moreover, the characteristics of tumor-infiltrating lymphocytes are associated with the effectiveness of immunotherapy. Preclinical studies have identified stimulatory dendritic cells, conventional dendritic cells, and macrophages as potential biomarkers. The emergence of single-cell sequencing and spatial transcriptomics has provided invaluable insights into tumor heterogeneity through the lens of single-cell profiling and spatial distribution. With the widespread adoption of next-generation sequencing, certain genomic characteristics, including tumor mutational burden, copy number alterations, specific genes (TP53, CTNNB1, and GZMB), and signaling pathways (WNT/β-catenin) have been found to correlate with prognosis. Furthermore, clinical features such as tumor size, number, and metastasis status have demonstrated prognostic value. Notably, common indicators such as the Child-Pugh score and Eastern Cooperative Oncology Group score, which are used in patients with liver diseases, have shown potential. Similarly, commonly employed laboratory parameters such as baseline transforming growth factor beta, lactate dehydrogenase, dynamic changes in alpha-fetoprotein (AFP) and abnormal prothrombin, CRAFITY score (composed of C-reactive protein and AFP), and immune adverse events have been identified as predictive biomarkers. Novel imaging techniques such as EOB-MRI and PET/CT employing innovative tracers also have potential. Moreover, liquid biopsy has gained widespread use in biomarker studies owing to its non-invasive, convenient, and highly reproducible nature, as well as its dynamic monitoring capabilities. Research on the gut microbiome, including its composition, dynamic changes, and metabolomic analysis, has gained considerable attention. Efficient biomarker discovery relies on continuous updating of treatment strategies. Next, we summarized recent advancements in clinical research on HCC immunotherapy and provided an overview of ongoing clinical trials for contributing to the understanding and improvement of HCC immunotherapy.