Current Perspectives and Trend of Acupuncture in Breast Cancer-Related Symptoms: A Bibliometric Study

Introduction

Breast cancer (BC) is the most common female malignancy, accounting for 30% of all female malignancies.¹ Globally, BC affects about 2.1 million people a year.² Due to early diagnosis and better treatments, the mortality rates in BC have steadily fallen in recent years.³ The most commonly used treatment approaches for BC include surgery, endocrine therapy, and chemotherapy.⁴ However, these treatments are accompanied by significant adverse effects.⁵ BC survivors not only experience physical problems including pain and gastrointestinal reactions, but also mental problems such as insomnia and post-traumatic stress disorder.⁶ Multiple studies reported that 60% to 100% of BC patients experience at least one menopausal symptom,⁷ 36.2% of survivors suffered from post-mastectomy pain syndrome,⁸ and 2% to 77% suffered from lymphedema. Meanwhile, up to 32.2% of BC survivors were estimated to have negative emotions.⁹ As the long-term survival rate has gradually improved, more emphasis has been placed on assisting survivors in managing the side effects of BC therapy that may impact function and quality of life (QOL).

Finding a safe and effective strategy to enhance the QOL of BC survivors is critical. Based on suggestions from international clinical practice guideline development groups, acupuncture is a safe and ancient medical therapy for a number of cancer-related symptoms.¹⁰ Numerous clinical studies on the efficacy and safety of acupuncture for treating BC-related symptoms have been published over the past 30 years.¹¹ For example, acupuncture not only could significantly relieve joint pain associated with aromatase inhibitors among BC survivors,¹² but it could also minimize the opioid dose and treat opioid-related adverse effects.¹³ Meanwhile, Chien reported that acupuncture dramatically attenuated BC-related menopausal symptoms, and treatment gains were maintained up to 3 months after the completion of treatment.¹⁴ Therefore, analyzing the application trends, research status, and hotspots of acupuncture for BC-related symptoms is critical for use with acupuncture in clinical practice and deeper fundamental research.

Bibliometrics has been extensively used in diverse clinical fields as an emerging method in recent years.¹⁵ It is the application of statistical and mathematical techniques to scholarly publications, revealing multiple facets and study trends in that area.¹⁶ In addition, the quantity of bibliometrics literature has exponentially increased over the past few years. Citespace is the most commonly used information visualization software based on citation analysis theory.¹⁷ VOSviewer visualizes literature data in a multivariate, time-phased, and dynamic citation analysis language.^16,18 Using the Bibliometric software to examine articles in the R language environment is simple and quick.¹⁹ In recent years, acupuncture-related bibliometrics have grown exponentially, including acupuncture for pain,²⁰ depression,²¹ and inflammation.¹⁷ To the best of our knowledge, acupuncture therapy’s effects on BC-related symptoms have not yet been the subject of a thorough bibliometric analysis.

In this study, we use the bibliometric approach and scientific knowledge map to graphically analyze the research progress, current status, and hotspots of acupuncture for BC-related symptoms throughout the previous 30 years from multiple perspectives. We also predict future research trends in this area.

Material and Methods

Source of Data and Search Strategy

The data was gathered from the Web of Science Core Collection (WoSCC) database. The WoSCC was selected because it is the most extensive and frequently utilized database, embodying the most significant and appropriate journals.²² The search method included the topics “breast neoplasm” and “acupuncture therapy”, with the limited time set from 1993 to 2023. Literature that was an article or review was included, and the language was set to English. Table 1 displays the precise search techniques and outcomes.

Table 1 The Topic Search Query

Data Collection and Analysis

The data were retrieved by two independent reviewers from the WoSCC database. Any differences were settled by the decision of a third senior reviewer. With the help of the intrinsic function of WoSCC, the publication features were analyzed to provide a number of bibliometric parameters, primarily the Hirsch index, yearly publications, the output of countries, journals and citations. Furthermore, the impact factor of every journal was calculated using the Journal Citation Reports 2022 edition.

Data were transformed to “txt” format, designated “download_*.txt”, and then loaded into the “bibliometrix” package in the R environment (version 4.2.3), VOSviewer, bibliometrics (http://bibliometric.com/), and CiteSpace V6.1.6 for analysis (Figure 1). The “bibliometrix” package in the R environment (version 4.2.3) function was used to automatically transform and analyze the bibliographic data of the selected articles. We analyzed information related to countries, the author’s countries and keywords. The collaborative networks between institutions and authors were examined using VOSviewer. The collaborative analysis of countries was specifically plotted using the bibliometrics website. CiteSpace’s parameters were set as follows: (1) time slice: 1993–2023, 1 year per slice; (2) node type was chosen at a time; (3) 50 best items were used as selection criteria; (4) pruning: pathfinder. In addition, the timeline view of co-cited references and all items’ keywords were captured, along with powerful citation burst maps.

Figure 1 Flow-chart of the study.

Results

Analysis of Annual Publications

The volume of literature in a field and its changing trend can reflect the development stage. A total of 621 documents about acupuncture in BC research were included, including 442 “Articles” and 179 “Review Articles”. Although the time frame of our search was nearly 30 years, Figure 2 demonstrates that the first study in this field was published in 1995. From 1995 to the present, the number of publications shows a gradual upward trend over time. It is important to mention that there has been a substantial increase in 2018. Based on the time of publication and quantitative characteristics of the literature, research on acupuncture BC may be separated into two phases, namely the basic phase (1995–2017) and the significant growth phase (2018–2022). 272 documents were published, accounting for 51.04% of the total in Period 2. We anticipated that 85 papers would be written on acupuncture for BC in 2023 based on the fitting curve.

Figure 2 Annual trends of global scientific publications from 1995 to 2023.

Analysis of Countries

Forty-nine countries published more than one paper on acupuncture for the BC study between 1995 and 2023. Table 2 depicts the ten most productive nations and regions. The USA published the most papers (n = 226, 36.39%), followed by China (n = 159, 25.60%) and South Korea (n = 51, 8.21%). USA had the most citations (8936 times), the highest H-index (49) and centrality (0.33). The map of cross-country collaborations shows the density of collaboration between countries (Figure 3A). The USA has research collaborations with many countries, with China Canada, and UK collaborating most closely. However, the level of collaboration between other countries is lower. In Figure 3B, we find that the USA has long been in first place in terms of annual postings until 2015. China’s annual publication volume jumped in 2015 and was roughly equal to the USA in the following years, surpassing it in 2019. As shown in Figure 3C and D, papers in acupuncture for BC were mostly published in North America, Asia, and European nations.

Table 2 Top 10 Productive Countries Related to Acupuncture for BC

Figure 3 (A) Country Collaboration Map. (B) The changing trend of the annual publication quantity in the top ten countries from 1995 to 2023. (C) The international collaborations’ visualization map of countries/regions. (D) Corresponding Author’s Countries.

Analysis of Institutions

These papers were contributed by 1011 institutions, with a total of 161 papers being provided by the top 10 institutions, accounting for 25.93% of all the publications (Table 3). Memorial Sloan Kettering Cancer Center ranked first (n = 37, 5.96%), followed by Columbia University (n =17, 2.74%). Memorial Sloan Kettering Cancer Center is ranked first in terms of intermediary centrality, indicating that it is very influential in the field of acupuncture for BC. Meanwhile, we noticed that although Harvard University is only 7^th in relation to the number of articles published, it is second in terms of intermediary centrality at 0.13, indicating that this institution is also making an important contribution to the field.

Table 3 The Top 10 Productive Institutions Ranked by the Numbers of Publications

Authors and Co-Cited Authors

Over 3212 authors and 14,391 co-cited authors are included in this area of study. Among these authors, the top three were Mao, Jun J. (n = 27, 4.35%), Ben-arye, Eran (n = 15, 2.41%), and Bao, Ting (n = 12, 1.93%). The term “co-cited authors” refers to authors who have two (or more) writings referencing them at the same time. Among the leading 5 co-citation authors, Molassiotis, A. (n = 167, 26.89%) ranked first, followed by Mao, Jun J. (n = 144, 23.19%), and Deng G. (n = 110, 17.71%). Author/co-cited author collaboration network visualization is depicted in Figures 4A and B. There is close cooperation between authors, and the centrality of each author is much less than 0.1.

Figure 4 A network map showing authors (A) or co-cited authors (B) involved in acupuncture in research in relation to BC.

Analysis of Journals and Cited Journals

The 621 articles collected were allocated to 217 publications. The top 10 journals published roughly 32.37% of all publications (Table 4). Among them, Integrative Cancer Therapies ranked first (47 articles, 7.57%), followed by Supportive Care in Cancer (36 articles, 5.79%) and Journal of Alternative and Complementary Medicine (19 articles, 3.06%).

Table 4 The Top 10 Journals Involved in Research on Acupuncture in Relation to BC

The top three co-cited journals were the Journal of Clinical Oncology, Support Care Cancer, and Breast Cancer Research and Treatment (Table 5). This suggests that these journals hold significance in acupuncture research for the treatment of BC. The Jama-Journal of the American Medical Association, with the highest impact factor (IF) of 157.335, was also quite active.

Table 5 The Top 10 Co-Cited Journals Involved in Research on Acupuncture in Relation to BC

Figure 5 demonstrates that the majority of the articles were published in the field of “Medicine, Medical, and Clinical” on the left, with three important outward citation paths visualized as green curves, and they were significantly influenced by the fields of “Molecular, Biology, Genetics”, “Health, Nursing, Medicine”, and “Psychology Education Social”.

Figure 5 A network map showing Journals and Co-cited Journals involved in acupuncture in research in relation to BC.

Analysis of References

Table 6 presents the top ten papers ranked by co-citation frequency in descending order. The ten most co-cited references include one clinical practice guideline, two systematic reviews, and seven clinical studies. Excitingly, one clinical study was the most cited paper in the area from 1993 to 2023. These references were published in important and renowned journals. The review that had the greatest centrality of co-cited sources was in the journal of BREAST.

Table 6 Top 10 Co-Cited References with the Highest Frequency

According to the dynamics of the research area, Figure 6 displays the top 25 references in the citation boom that occurred throughout the growth of acupuncture for BC research from 1993 to 2023. References with high strength levels are usually significant turning moments in the scientific mapping area. The milestone paper is a clinical trial of acupuncture on aromatase inhibitor-related joint pain.¹² This literature can be broadly categorized into two phases: the first phase of research focuses on clinical studies related to acupuncture for the treatment of vasodilatory symptoms of BC, especially hot flashes; the outbreak of literature in the last decade can be categorized as the second phase, where research is being transformed into clinical studies related to acupuncture for the treatment of pain and peripheral neuropathies of BC and related guidelines.

Figure 6 Top 25 references with the strongest citation bursts from 1995 to 2023.

The cluster analysis of reference allowed us to observe those 10 clusters. Four of these clusters correlated with disease names, including #3 menopausal problem, #4 inhibitor-induced arthralgia, #6 reducing hot flash, and #7 night sweat. Another quartet focused on treatment techniques such as #0 cancer care, #1 acupuncture therapy, #2 alternative therapeutic approaches, and #9 Chinese medicine. The top ten clusters that were most recently active included #1 acupuncture therapy, #4 inhibitor-induced arthralgia, and #5 nonspecific effects (Figure 7).

Figure 7 References cluster time-line map related to acupuncture on BC from 1995 to 2023.

Analysis of Keywords

Publications yielded a total of 2171 keywords related to acupuncture for BC. Since 1993, a total of 25 keywords have experienced significant bursts. Figure 8 shows that keywords such as inhibitor-induced validation (2018–2023), inhibitor induced arthralgia (2019–2023), cancer pain (2019–2023), fatigue (2019–2023), therapy (2020–2023), induced peripheral neuropathy (2020–2023), safety (2020–2023), electroacupuncture (2021–2023), pain (2021–2023), and risk factor (2021–2023) have gained prominence in recent years. This indicates that research concerning these topics is currently garnering attention and signifies potential developmental trends in the field.

Figure 8 Top 25 keywords with the strongest citation bursts from 1995 to 2023.

A cluster analysis of the keywords revealed 10 clusters. These clusters pertained mostly to disease name (#1, #3, #4), treatment (#0, #2, #5, #6, #8), and mechanism (#7). For a deeper exploration of characteristics of the temporal evolution of the knowledge base in acupuncture for BC, cluster analysis was performed using the timeline view tool of CiteSpace (Figure 9). The clusters that were most recently active included #0 complementary therapies, #1 hot flashes, #3 symptom cluster, #4 nausea, #5 trial, and #8 traditional Chinese medicine.

Figure 9 Keyword cluster time-line map related to acupuncture on BC from 1995 to 2023.

Thematic evolution maps offer an alternative perspective on identifying research hotspots and trends. From 1995 to 2012, the primary research focus was on “prevalence”. The mainstream research topic shifted to “Quality of life” during the years 2013–2016, while “fatigue” emerged as a novel keyword from 2017–2019. In particular, the research on acupuncture for BC from 2020 to 2023 showed a notable increase in the appearance of “mechanisms” and “expression” (Figure 10A).

Figure 10 (A) Thematic map of keywords. (B) Keyword evolution analysis.

Moreover, we constructed a thematic map of hotspots, as shown in Figure 10B. The upper right quadrant, exemplifying strong centrality and high density, indicates that the research themes symbolized by the keywords in this region are highly popular. Consequently, prevalent themes during the period 1993–2003 include”hypnosis””clinical oncology program””risk factors””validation”,and”functional assessment.

Discussion

General Information

For this particular investigation, we conducted a thorough exploration of the WoSCC databases to locate articles related to acupuncture for BC that were published between 1995 and 2023. This scientometric study comprised 621 articles published in 217 journals by 1011 institutions in 49 countries.

We can classify three-decades of development into two periods as the basic phase (1995–2017) and the significant growth phase (2018–2022). There was an increased number of patients developing complications such as pain, acupuncture has been widely used with its unique advantages in analgesia.²³ Aromatase inhibitors (AIs) have been included in the 2018 treatment guidelines for BC. About half of women who take AIs develop arthritis-like joint stiffness and pain, some clinical evidence suggests that acupuncture can successfully manage joint stiffness and pain.²⁴ Consequently, research on BC acupuncture therapy-related research has developed to a new level.

The number of articles published in the USA was far in advance and had taken the lead. One in eight women is likely to have BC, indicating that the USA is a country with a high rate of BC.²⁵ That could be hundreds of millions of dollars a year in research funding in the United States.²⁶ China was the only developing nation among these ten most published countries, which is closely linked with the increased provision in the medical field.²⁷ Memorial Sloan Kettering Cancer Center, established in 1884, is consistently ranked in the top two of the best hospitals in the United States for cancer specialties. Mao Jun J., Bao Ting and Deng Gary are leading members of the institution researching the field.

The top four active authors were from the United States. This finding may mean that US researchers have made a significant contribution to this study. In terms of co-cited authors, the top ranking was Molassiotis Alex, followed by Mao Jun J. and Deng Gary. Molassiotis Alex (The Hong Kong Polytechnic University) is widely recognized for his substantial contributions to the development of clinical practice guidelines for evidence-based combination therapy for BC.²⁸ Mao Jun J.’s research is important for reducing peripheral neuropathy induced by neoadjuvant paclitaxel in BC patients.²⁹ Deng Gary focused on the study of acupuncture for dyspnea in BC patients and chronic fatigue after chemotherapy.³⁰

Knowledge Base

The top 10 co-cited journals are mostly top-tier publications and consist of seven clinical trials, two reviews, and one clinical practice recommendation. Seven clinical studies outline the process of discovery and development of acupuncture for BC-related symptoms. The seven clinical studies included acupuncture for vasodilatory symptoms in women with BC-related symptoms,^31–34 aromatase inhibitor-related joint pain,^12,35 and cancer-caused fatigue.³⁶ Research shows acupuncture’s increasing popularity as an alternative medicine worldwide due to its effectiveness. A high-IF study by Hershman included 226 early-stage BC patients who were taking AIs through a multicenter collaboration. They concluded that the true acupuncture group significantly reduced joint pain at 6 weeks.¹² However, accuracy issues were found in their test results.

Three articles, consisting of one clinical practice guideline and two systematic reviews, were examined. Meta-analyses and systematic reviews of RCT showed that acupuncture is effective in reducing cancer pain, nausea and can reduce the use of painkillers.^37,38 Additionally, in 2017, the Society for Integrative Oncology issued a clinical practice guideline that highlighted the role of acupuncture in symptom relief and acupuncture for the treatment of chemotherapy-induced nausea and vomiting (CINV) with a “B” grade of recommendation.²⁸

Research Hotspots

The research hotspots, in addition to the symptoms such as pain and vasodilatory symptoms, which are also focused on QOL and electroacupuncture, are major highlights of the treatment.

Over 70% of advanced cancer patients experience moderate to severe pain,³⁹ adding to the current opioid crisis and highlighting the need for nonpharmacological treatments.⁴⁰ An evidence-based guideline strongly recommends acupuncture for arthralgia-induced pain,¹³ especially in patients receiving aromatase inhibitors. A network meta-analysis of 17 RCTs involving 1516 participants ranked acupuncture as the top intervention for improving pain intensity,⁴¹ showing acupuncture plays a great role in pain management. Apart from this, multiple RCTs suggested acupuncture can reduce CINV,⁴² despite its limited role in prevention.⁴³ Importantly, acupuncture can also alleviate vasomotor symptoms like hot flushes and night sweats, which are prevalent in 65% of postmenopausal BC patients.⁴⁴ As the number of survivors increases, addressing these symptoms becomes crucial.⁴⁵ Hormone replacement therapy (HRT), often used for hot flashes, is controversial in BC patients.⁴⁶ Clinical studies have shown that acupuncture is effective in relieving hot flashes without elevating estradiol levels or inducing cancer recurrence.³³ The underlying mechanism of acupuncture, possibly by increasing in endorphin levels and reducing the level of the potent vasodilator calcitonin gene-related peptide continues to be a focus.⁴⁷ Moreover, acupuncture seems to significantly improve night sweats in BC survivors.⁴⁸ Measuring treatment effects on QOL is crucial, particularly for BC patients undergoing therapies such as anthracyclines (ANT), which often have significant side effects.^49,50 Acupuncture is effective in the secondary prevention of myelosuppression during chemotherapy, and QOL improves in women during treatment.⁵¹

Electroacupuncture, which combines electrostimulation and traditional acupuncture needling, cannot only improve treatment efficiency but also be a targeted route of drug delivery. Preliminary findings suggest electroacupuncture can promote paclitaxel accumulation by altering the microvasculature and microenvironment of mouse BC tumors.⁵² In addition, electroacupuncture significantly induced apoptosis in the tumors.⁵³ Mechanistic analyses have shown that electroacupuncture has been shown to directly decrease triple-negative breast cancer (TNBC) tumor growth by inhibiting proteins involved in tumor angiogenesis and extracellular matrix, suppressing triple-negative BC-induced inflammation, and upregulating nerve growth factor receptors.⁵⁴ Therefore, future studies should focus on how acupuncture plays various roles in a more targeted way during each stage of BC.

Research Frontiers

Pain is not only a current research hotspot; we predict that it is also a future research trend. In order to better investigate and characterize the cutting-edge field, we conducted a keyword and co-citation analysis of the keywords and co-cited literature for emergence and clustering. Current studies focused on “chemotherapy-induced peripheral neuropathy (CIPN)”, “cancer-related fatigue (CRF)” and “nonspecific effect”.

CIPN poses a significant clinical issue for BC patients,⁵⁵ with a prevalence rate ranging between 30% and 97%.⁵⁶ Mostly, it results in paresthesia and pain, which, according to the current interventions, are not sufficiently addressed.⁵⁵ However, promising evidence from acupuncture studies suggests pain reduction and enhanced nerve conduction in CIPN patients.⁵⁷ While findings from a phase IIA trial indicate acupuncture’s potential in reducing CIPN’s severity among BC patients undergoing neoadjuvant therapy,²⁹ it is essential to note the necessity for larger-scale studies to solidify these conclusions.

CRF has received inadequate attention, diagnosis, and care. A Study tracking fatigue trajectories in BC patients found that high fatigue is often accompanied by depressive tendencies and higher rates of sleep disorders.⁵⁸ A randomized controlled study found that acupuncture relieved physical and psychological fatigue and reduced the incidence of anxiety and depression.³⁶ Acupuncture should be advocated as an effective alternative therapy for CRF patients, particularly those with BC.⁵⁹ According to research, acupuncture works to reduce fatigue by influencing the variety and amount of intestinal bacteria, enhancing intestinal barrier performance, and modifying brain gut peptides.⁶⁰ With the advancement of genome and transcriptome sequencing, they showed that acupuncture can improve CRF in BC by blocking the Leptin/AMPK signaling pathway and thereby minimizing mitochondrial functional impairment.⁶¹ While acupuncture presents several potential benefits in BC treatment, particularly in managing CIPN and CRF, future studies need to provide larger samples and maintain stringent controls to ensure the results’ validity and reliability.

Increasing evidence shows that acupuncture therapy has nonspecific effects in addition to specific therapeutic effects.⁶² Meta-analysis has shown that the clinical efficacy of “comfort needling” is also influenced by nonspecific effects and that comfort needling has some specific potency due to the contact of the treatment modality with the skin, resulting in the projection of somatosensory fibers to various brainstem nuclear area and hypothalamus.⁶³ Acupuncture does not only provide analgesia by suppressing the sensation of pain, but it can also provide analgesia by intervening on emotions and cognitions (expectations) to relieve the sensation of pain.⁶⁴ To further measure the specificity impact of acupuncture and to encourage the growth of acupuncture on a global scale, sham acupuncture control should be implemented in a way that minimizes the influence of factors such as patient-doctor communication, patients’ expectations, and the attitude of the practitioner.

Strengths and Limitations

Our study provides a systematic analysis of acupuncture treatment for BC-related symptoms, which can provide some guidance. We also used multiple bibliometric programs to analyze the research hotspots and trends in multiple dimensions. However, this study has several drawbacks. First, we just included articles from WoSCC. Again, the retrieved articles were limited to those published in English. Finally, complete annual data for 2023 is not yet available, new hotspot areas may have been missed, and further updates are needed for future studies.

Conclusion

In summary, acupuncture treatment for BC-related symptoms is a challenging subject in clinical and basic research. Acupuncture treatment for BC-related symptoms is a relatively new field, receiving increased attention since 2018. The use of acupuncture in symptom management of BC has been broadening and the scope of research has gradually overstepped from single symptom management to an integrated oncology treatment model. A number of clinical trials have been conducted to validate the efficacy and safety of acupuncture therapy for the treatment of BC-related symptoms, with studies focusing on acupuncture’s improvement of BC-related symptoms and adverse effects after BC treatment. There are increasing studies on acupuncture in the treatment of pain, vasodilatory symptoms, CIPN, and CRF. These are important for promoting the use of acupuncture therapy and improving the quality of life of BC patients. Improving these symptoms and studying their mechanisms will be the focus of future research. In the future, basic and translational research should be carried out to reveal the mechanism of the effect of acupuncture and moxibustion, and at the same time, multi-center and large sample RCTs should be conducted to provide more credible data, and multi-methods combination therapy research should be carried out to enrich and standardize the treatment of breast cancer, so as to bring about a new development and change in the field.