Global trends in research on radiofrequency ablation for lung cancer: a bibliometric and visualization analysis (2008–2024)

Introduction

Lung cancer is the leading cause of cancer death in the world, accounting for about 18% of all cancer deaths (1). According to Global Cancer Observatory (GLOBOCAN) 2020 data, the global incidence of lung cancer has been on the rise in the past few decades. It is expected that the number of new cases and deaths from lung cancer will continue to increase until 2050, which will make lung cancer a major global public health challenge (2).

The treatment options for lung cancer are diverse, including surgery, chemotherapy, radiotherapy, targeted therapy, immunotherapy, and local treatment etc. For early-stage non-small cell lung cancer (NSCLC), surgical resection is the preferred treatment method. However, for patients who are not eligible for surgery, stereotactic body radiotherapy (SBRT) has been established as the standard treatment method, with high local control rates and survival rates. For those high-risk patients who are not suitable for SBRT, radiofrequency ablation (RFA) may be an appropriate option.

RFA has emerged as an important alternative treatment option due to its minimally invasive nature, precise targeting, potential for repeat treatment, and rapid recovery advantages, especially for patients who have contraindications to SBRT (3). Compared with traditional surgery, RFA only needs to insert a fine needle into the skin, which causes less trauma and the postoperative recovery time is greatly shortened (4). This property makes this method especially suitable for those patients with pulmonary dysfunction or other comorbidities (5). Clinical studies have shown that RFA has a significant effect on peripheral lung cancer lesions with a diameter ≤3 cm, especially for cases with clear tumor boundaries and far away from the bronchus and large vessels (6,7). RFA has become an increasingly important treatment option, providing new hope for lung cancer patients, especially those who cannot undergo traditional surgery or SBRT treatment, to improve the quality of life and prolong the survival time (4,8).

This study represents the first comprehensive bibliometric assessment of RFA in lung cancer research, whose purpose is to draw the scientific network in the field of RFA of lung cancer in the past through bibliometric analysis, reveal the research hotspots and frontiers in this field, further improve the understanding of relevant scientific knowledge, and better explore the potential research directions in the future. We present this article in accordance with the BIBLIO reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1035/rc).

Methods

Data source and retrieval strategy

Publications between 01 January 2008 and 31 December 2024 were retrieved from the Web of Science Core Collection (WoSCC) database. The study strategies were as follows: TS= (“pulmonary” OR “lung” OR “respiratory organ”) AND (“cancer” OR “cancers” OR “tumor” OR “tumors” OR “tumour” OR “tumours” OR “neoplasms” OR “neoplasm” OR “carcinoma” OR “carcinoma” OR “carcinomas” OR “carcinomatosis” OR “malignancy” OR “malignancies” OR “malignant”) AND (“RFA” OR “Radiofrequency ablation”). The publication language was limited to English, and the literature type was limited to an article. Duplicate articles and articles that were not relevant to the topic were excluded. A total of 1,367 articles were retrieved, and the search work was completed independently by three researchers. The specific process is shown in Figure 1.

Figure 1 Literature search flow chart.

Data analysis

According to the search strategy, we retrieved a total of 1,367 valid literatures in WoSCC and exported these literature in the form of pure text files, which were imported into CitseSpace and VOSviewer, respectively. The ranking of countries, institutions, and journals was based on publication volume, and the results were converted to rank order using the standard competition ranking. Microsoft Office Excel was used for descriptive statistical analysis and chart drawing to analyze the changing trend of the number of publications. VOSviewer software was used to conduct country/regional cooperation network analysis, institution cooperation network analysis, journal cooperation network analysis, author cooperation network analysis, author co-citation analysis, literature co-citation analysis, and keyword co-occurrence analysis of the included 1,367 literature. CiteSpace software was used for keyword mutation analysis, keyword cluster analysis, keyword time map analysis, and literature co-citation mutation analysis. Through the construction of a visual knowledge graph, this cross-dimensional research method realizes the structured presentation of the academic field research context, which can not only trace the evolution trajectory of the discipline, but also identify frontier hotspots and provide support for systematic knowledge discovery.

Results

Trend of publication

Figure 2 illustrates annual publications on lung cancer RFA, showing an overall rise-then-fall trend with fluctuations. The annual publication volume in the field of RFA for lung cancer has shown a fluctuating growth trend. The initial record in 2008 was 58 articles, which showed a slight fluctuation in the early stage and significantly increased to 93 articles in 2011. The research activity remained at a high level from 2014 to 2018, with a peak of 100 articles reached for the first time in 2015. From 2019, there was a temporary decline, dropping to a low of 67 articles in 2020, but then rebounded rapidly, recovering to 93 articles in 2021 and continuing the upward trend. In 2024, the publication volume returned to the historical high of 100 articles.

Figure 2 Trend chart of publications.

Collaborative network analysis of countries, institutions, and authors

The author analyzed the countries and regions of publication, and the visual map is shown in Figure 3A,3B. The larger the node, the more the number of publications. The top ten countries with high output of articles are shown in Figure 3C. China has shown significant academic influence in this field, ranking first in the world with 413 articles, reflecting China’s core position in the research of RFA of lung cancer. The VOSviewer map further reveals the characteristics of the cooperation network between countries and regions.

Figure 3 Each country/region’s contribution to the radiofrequency ablation of lung cancer. (A) The visualization network of country/region related to the radiofrequency ablation of lung cancer; (B) the density map of country/region related to the radiofrequency ablation of lung cancer; (C) number of publications by country.

Figure 4 and Table 1 detail institutional publications. Chinese institutions led in volume but had lower average citations (ACs) and H-index. Conversely, US institutions and French institutions demonstrated greater impact per paper. The co-occurrence map (Figure 4A) and density map (Figure 4B) indicate a US/France-centered international collaboration network, while Chinese collaborations were primarily domestic. Increased international cooperation appears essential for enhancing Chinese institutions’ influence.

Figure 4 Each institution’s contribution to the radiofrequency ablation of lung cancer. (A) The visualization network of country/region related to the radiofrequency ablation of lung cancer; (B) the density map of country/region related to the radiofrequency ablation of lung cancer.

Author co-occurrence analysis (Figure 5A) revealed three distinct collaborative clusters in lung RFA research. The blue cluster featured Asian scholars, primarily focused on clinical applications and multi-center studies. The red cluster included authors such as Deschamps Frederic and Xu Sheng, often collaborating internationally, suggesting work in image-guided technologies and combination therapies. The green cluster comprised mainly Japanese researchers, likely concentrating on complication management and long-term outcomes. The author density map (Figure 5B) highlighted influential figures including Solomon (US), de Baere (France), and Yamakado (Japan), alongside significant representation of Asian researchers, confirming strong regional research activity. Temporal analysis (Figure 6) showed sustained engagement over the past decade, with notable author growth post-2016 potentially reflecting technological maturity.

Figure 5 Each author’s contribution to the radiofrequency ablation of lung cancer. (A) The visualization network of authors; (B) the density map of authors.

Figure 6 Time trend graph of authors.

Analysis of journal publication

A total of 397 journals published original articles on RFA treatment of lung cancer. Visual analysis of the published journals is shown in Figure 7A,7B; the size of nodes represents the number of published journals, and the top ten published journals are shown in Table 2. It can be seen that Journal of Vascular and Interventional Radiology [88 articles, total citations (TCs) =3,024, total link strength (TLS) =27,689] and Cardiovascular and Interventional Radiology (TC =1,900, TLS =23,057) were the leading journals in both publication volume and citation count. It highlights the dominant position of interventional radiology in this field. The Journal Citation Reports (JCR) divisions of these journals are basically Q2 and above, and they have a high impact factor (IF), reflecting their academic authority and discourse power.

Figure 7 Each journal’s contribution to the radiofrequency ablation of lung cancer. (A) The visualization network of journals; (B) the density map of journals.

References analysis

References were analyzed using CiteSpace to generate a reference emergence map (Figure 8) and a timeline map (Figure 9). These literatures reveal the research dynamics and knowledge evolution characteristics of RFA field. From the perspective of time span and citation outbreak Strength, the research can be divided into three stages: the first stage is the technology exploration and preliminary verification stage (2008–2012). The second stage was the clinical expansion and multidisciplinary integration stage (2013–2016). The third stage is the technology optimization and comprehensive treatment stage (2016–2024).

Figure 8 Top 25 references with the strongest citation bursts.

Figure 9 The timeline view of references.

Keywords co-occurrence, mutation and cluster analysis

The keywords co-occurrence network diagram (Figure 10A,10B) constructed by VOSviewer shows that there are four clusters of blue, green, red and yellow. The blue cluster focused on “cryoablation”, “microwave ablation”, “cell lung cancer” and “radiotherapy”, and focused on the diversity of local ablation techniques and their combined treatment strategies. The green cluster focused on “thermal ablation”, “safety”, “complications” and “pneumothorax”, highlighting the safety assessment and risk management of ablation treatment. The red cluster focused on “radiofrequency ablation”, “metastases” and “follow-up”, reflecting the clinical application and long-term management of RFA in the treatment of lung metastases. The yellow cluster was centered on “management”, “outcomes”, “survival” and “recurrence”, covering the comprehensive management and prognosis of multiple cancer ablation treatments. The Atlas, as a whole, presents a progressive logic from technical exploration, safety verification to clinical application of multiple cancers, highlighting the multi-dimensional research pattern of RFA in the treatment of lung cancer and metastases.

Figure 10 Keyword co-occurrence graph. (A) The visualization network of keywords; (B) the density map of keywords.

CiteSpace’s keyword timeline (Figure 11) reveals evolving research foci. Early work centered on foundational treatments, dominated by large-node keywords “non-small cell lung cancer” (#0) and “radiation therapy” (#1), indicating significant literature volume. Two years later, “thermal ablation” (#2) emerged with strong links to #0 and #1, marking its systematic application in lung cancer. The mid-stage focused on technical optimization and expanded indications: “microwave ablation” (#4) succeeded earlier thermal ablation, while co-occurring nodes “liver metastases” (#3), “lung metastases” (#9), and “liver resection” (#5) revealed increased cross-organ application in metastases; node color shifts also signaled greater clinical translation. Recent trends show refinement: “complication” (#8, largest node) strongly linked to “tumor ablation” (#6), highlighting safety assessment as a priority. Newer keywords like “live metabolism” and “mice induce” indicate exploration shifting towards molecular mechanisms.

Figure 11 The timeline view of references.

In addition, Tables 3,4 show the top 20 keywords ranked by frequency and centrality. The burst intensity of the top 25 keywords was analyzed by Citespace. Figure 12 shows the concentrated explosion period in the field of RFA treatment of lung cancer from 2008 to 2024. Early studies focused on “risk factors” and “prognostic factors” and other prognostic evaluations. In recent years, the hot research has turned to precision medicine, such as “diagnosis” (strength 5.88, 2013–2024), “cryoablation” (strength 5.78, 2021–2024), “microwave ablation” (strength 15.24, 2019–2024), indicating precision medicine is actively revolutionizing both diagnosis AND treatment, with minimally invasive targeted ablation currently representing the most explosive area of research activity within the therapeutic side. It is worth noting that the continuous high citation of keywords such as “liver resection” and “complications” highlights that the safety optimization of ablation technology is still the clinical focus.

Figure 12 Top 25 keywords with the strongest citation bursts.

Discussion

We performed the first bibliometric analysis of the research progress and literature on RFA treatment of lung cancer. The publication volume related to the RFA for lung cancer shows a trend of “first increasing and then decreasing”, which may stem from the increasing dominance of SBRT as the primary non-surgical ablative modality for inoperable early-stage NSCLC, combined with rapid advances in immunotherapy (9,10), explaining why the research on ablation has shifted to radiology journals rather than thoracic oncology journals. These developments underscore the competitive pressures facing RFA and urgently warrant focused research to define its unique value, particularly for specific subgroups or synergistic combination approaches. Our findings reveal distinct global contributions that China leads in publication volume, while U.S. and French institutions dominate in academic influence, underscoring a “volume-impact gap” among regions. Among Chinese institutions, Sun Yat-sen University (TC =826) and Fudan University (TC =445) had higher TC, but there was still a gap compared with the top institutions in other countries, which shows the characteristics of “quantitative and qualitative differentiation”. The cooperation network analysis reveals multipolar research development: the U.S., France, Japan, and China form regional clusters with complementary specialization. Despite this regionalization, emerging transnational author collaborations indicate potential for deeper integration. Future efforts should prioritize such global networks to accelerate clinical translation.

In the included research journals, Q1 journals (such as Radiology and European Radiology) had a higher general IF, reflecting their international academic discourse. The coexistence of clinical journals and basic journals indicates that the research of RFA is deepening multidisciplinary collaboration, especially in the fields of image guidance, hyperthermia optimization and patient prognosis, and increasingly, with disciplines such as radiation oncology, particularly regarding comparisons and combined approaches with SBRT (11). The research in the field of RFA of lung cancer is highly dependent on radiology and hyperthermia technology journals. Exploring connections with journals dedicated to radiation oncology and SBRT outcomes could provide valuable comparative insights and foster broader interdisciplinary synergy (12).

Through the analysis of references, it can be found that RFA research on lung cancer presents an evolutionary path from technical verification to clinical integration. In the early stage, Simon et al. and de Baere et al. focused on the treatment and short-term efficacy evaluation of RFA guided by computed tomography (CT) or ultrasound, and mainly explored by radiological techniques (13,14). In the middle stage, the application of RFA in metastatic lung cancer and locally advanced tumors had begun to receive attention, and the focus was on the long-term survival and complication management. Kashima et al. evaluated the feasibility, safety and efficacy of RFA in the treatment of inoperable malignant lung tumors through a prospective, multicenter, single-arm clinical trial, and found that RFA was safe and feasible in strictly selected patients with malignant lung tumors and could provide durable local control (15). The later stage is the technical optimization and comprehensive treatment stage, focusing on RFA combined with other methods. Research increasingly explores synergistic effects, particularly RFA combined with other modalities like chemotherapy or immunotherapy, and delves into the molecular mechanisms underlying treatment response and recurrence (16-18). In future studies, scholars can focus on the positioning of RFA in individualized treatment, the synergistic mechanism with other therapies, and the long-term efficacy verification based on real-world data.

Through in-depth analysis of the keyword co-occurrence map, the research in the field of RFA of lung cancer focuses on the following three directions: Firstly, technical collaborative innovation: microwave ablation (MWA) induces tumor cell death through local heating and may activate anti-tumor immune response (19,20). The study of Xu’s team showed that the combination of MWA and immune checkpoint inhibitors (ICIs) significantly improves the anti-tumor immune response and provides a new idea for clinical treatment (21). A multicenter study by Heerink et al. also demonstrated that MWA combined with radiotherapy could improve local control (22). Secondly, Precise prevention and control of complications: efforts are directed towards developing quantitative models and standardized protocols to better manage risks like pneumothorax, moving beyond empirical judgment. Thirdly, Whole process management of lung metastases: Although existing studies have shown that RFA is highly effective and safe for treating lung metastases, further studies are needed to optimize the operation technique, reduce the incidence of complications, and establish a better long-term follow-up mechanism (14,23,24). Additionally, through in-depth study of tumor metastasis-related genes and signaling pathways, researchers have revealed the mechanism of organ-oriented metastasis, which provides a theoretical basis for comprehensive management of tumor cycle (25,26). From the clustering map of keywords (Figure 10A), it can also be seen that a complete innovation chain of “technology evolution, safety verification, clinical practice, and prognosis optimization” has been formed in this field.

The dynamic evolution of the CiteSpace timeline map further confirms the phased characteristics of the field development. In the early stage from 2008 to 2012, NSCLC and radiotherapy were highly clustered, and the role of RFA as an adjuvant treatment was established. From 2013 to mid-2016, the cross-co-occurrence of MWA and metastatic tumor research, as well as the strong correlation between liver resection and liver metastasis, revealed the cross-organ extension of the research field from primary tumor to metastatic lesions. In the recent period after 2016, the significant prominence of complication nodes and the emergence of new keywords such as metabolomics indicate that this field is transforming from empirical medicine to the deep integration of evidence-based medicine and translational medicine.

Conclusions

The study reveals the global research status, technical development and future research direction in the field of RFA of lung cancer. The study reveals a distinct “quantitative-qualitative divergence” in China dominated in the number of publications, but European and American institutions led the academic influence with high citation frequency and H-index. Moreover, research in this field has evolved through distinct stages: from initial technical validation, to clinical extension in metastatic disease, and finally to the current hot spot, including technical collaborative innovation, precise complication control, whole-process management of metastases and whole-tumor cycle intervention. In the future, it is necessary to strengthen transnational cooperation networks, unify data labeling standards, and focus on real-world efficacy verification and molecular mechanism analysis, so as to accelerate the strategic upgrade of RFA from a local ablation technique to a whole-cycle tumor management paradigm. Future studies may need to strengthen multi-center long-term follow-up data to verify the long-term efficacy and survival benefits of ablation technology. In general, the field is evolving from technical exploration to individualization and interdisciplinary integration.

There are some limitations in this study. Although the data of this study are from the core collection of Web of Science, it covers high-quality English literature, it may not include research results from non-English speaking countries and conference papers not included in the WoSCC. Future studies can be combined with multi-database analysis such as PubMed and Scopus to more comprehensively reflect the global research trend.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the BIBLIO reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1035/rc

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1035/prf

Funding: This study was supported by the 13th Five-Year Plan Key Discipline Construction Program of Traditional Chinese Medicine (Integrated Traditional Chinese and Western Medicine) in Zhejiang Province (No. 2017-XK-A09), and Zhejiang Provincial TCM Academic Inheritance and Specialty Construction Project (No. 2A11543).

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1035/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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