2.1. Study Design

Unlike traditional literature studies that use qualitative and experimental methods, this bibliometric analysis takes a quantitative approach to assess research on dietary fiber in cancer management. The methodology examines publication metrics, temporal trends, journal distributions, and citation patterns to provide a systematic overview of the field. The analysis maps the research landscape and identifies influential works and emerging trends, analyzes the geographic and institutional distribution of research contributions, and highlights promising directions for future investigation. Through this comprehensive assessment, the study seeks to deepen understanding of dietary fiber’s role in cancer management and support the development of more integrated approaches to cancer care.

2.2. Data Description and Collection

The primary sources for data collection are Web of Science, PubMed, and Scopus databases, chosen for their extensive coverage across interdisciplinary and biomedical disciplines (see Figure 1). A detailed search strategy was formulated using a combination of keywords and phrases related to “dietary fiber” and “cancer management,” including their synonyms and variations. The search query was “dietary fiber” OR “dietary fiber” OR “soluble fiber” OR “insoluble fiber” OR “fiber intake” OR “fiber intake” OR “fermentable fiber” OR “inulin” OR “psyllium” OR “pectin” “B-glucan” OR “resistant starch” OR “fructan” OR “fructose” OR “fructo-oligosaccharides” OR “oligosaccharides”) AND (“cancer management” OR “cancer treatment” OR “cancer therapy” OR “chemotherapy” OR “radiotherapy” OR “immunotherapy” OR “cancer patient care” OR “oncology” OR “nutrition”). The search was delimited to the period from April 1999 to May 2024, aiming to capture the most relevant and contemporary insights over the past 25 years.

2.3. Criteria for Inclusion and Exclusion of Studies

The inclusion criteria targeted peer-reviewed articles published in English from Web of Science, PubMed, and Scopus databases, focusing on the intersection between dietary fiber and cancer management. This encompasses empirical research, review articles, and meta-analyses that contribute to understanding the role of dietary fiber in the treatment, management, or care of cancer patients. Documents included were full-text publications within the specified timeframe (1999–2024).

Exclusion criteria were applied to conference abstracts and proceedings, non-peer-reviewed articles, letters to editors, book chapters, preprints, documents not in English, and publications that, despite mentioning dietary fiber or cancer, do not specifically address the role of dietary fiber in cancer management.

2.4. Data Cleaning

Following the initial data retrieval, a meticulous data cleaning process was undertaken. This involved the removal of duplicate entries resulting from the overlap between the databases and the refinement of search strings to weed out irrelevant articles which resulted in 343 articles included in the study (Figure 1). The relevance of each article was assessed based on its title, abstract, and keywords, ensuring a focus on the study’s primary objective. The iterative optimization of search strings was instrumental in refining the dataset to a manageable and relevant collection of literature for analysis.

2.5. Data Analysis

For the analysis phase, the bibliometric data was analyzed using the ‘bibliometrix’ R package (version 4.1.0). This package was specifically used for calculating collaboration indices, generating co-occurrence networks, and performing thematic mapping. Citation metrics were analyzed using the ‘ggplot2’ package for visualization. For keyword analysis, VOSviewer software (version 1.6.18) was employed to create network visualizations and density maps. All statistical analyses were performed in R (version 4.2.0), with data preprocessing conducted using the ‘tidyverse’ suite of packages.

Key metrics were derived to highlight trends in publication volume over time, identifying the most influential articles and authors through citation analysis. The study also mapped out co-authorship networks to reveal patterns of collaboration among researchers and institutions, providing insights into the community’s structure. Keyword analysis further allowed the examination of research foci, emerging trends, and potential gaps in the existing literature, highlighting areas ripe for future exploration.

3.1. Publication Trends

3.1.1. Year-Wise Distribution of Publications

The analysis of publication trends, as depicted in Figure 2, reveals a consistent upward trajectory in scholarly output over the observed period. No peer reviewed article was found for 1999. During the early years (2000–2010), publication activity was relatively limited, reflecting the nascent state of the research field. Significant year-to-year fluctuations during this period suggest initial interest that was not yet sustained. The subsequent mid-period (2010–2015) saw a steady growth in scholarly contributions. This period likely reflects growing awareness and recognition of the field’s importance among researchers. Notably, in the recent period (2015–2023), there has been a pronounced increase in the number of publications. This surge in scholarly output, especially post-2020, suggests intensified research interest potentially driven by technological advances, policy shifts, or increased funding and collaborative opportunities.

The intensity of collaborative research, as indicated by the red line graph in Figure 2, highlights a notable evolution in the average number of authors per publication. In the early years (2000–2010), the limited collaboration, demonstrated by the relatively low average number of authors, aligns with the low overall publication output. The mid-period (2010–2015) shows a gradual rise in collaborative efforts, where research increasingly involved multiple contributors, likely due to growing interdisciplinary engagement. In the recent period (2015–2023), collaboration intensity has remained consistently high, with notable peaks in certain years. This trend signifies a transition to comprehensive, multiauthor projects, potentially enabled by the broadening of interdisciplinary collaborations, institutional partnerships, and advancements in communication technologies. The steady growth in collaboration reflects the field’s maturation and the recognition that addressing complex research problems benefits from diverse expertise and multi-institutional resources.

3.1.2. Geographical Distribution and Most Active Affiliations by Publications

The global distribution analysis depicted in Figure 3 reveals the concentration and reach of research activity across nations and institutions. Figure 3a employs color gradients to represent publication output by country, with darker shades corresponding to higher volumes. This mapping demonstrates the clear dominance of the United States and China in research productivity. The substantial American contribution reflects robust research infrastructure and funding mechanisms, while the strong Chinese presence aligns with strategic national initiatives to expand research influence. Additional significant contributions emerge from the United Kingdom, Germany, and Japan, though at lower volumes than the two leading nations. The participation of regions such as Brazil and Australia indicate broader international engagement, albeit at more modest levels compared to the primary research centers.

Figure 3b presents academic institutions by their publication output in this field of research. It highlights a clear hierarchy among the top 10 contributing institutions.

University of Texas MD Anderson Cancer Center demonstrates exceptional productivity with 35 articles, establishing it as the preeminent contributor. University of Utrecht follows with 26 articles, creating a notable gap between the first and second positions. University of Toronto and Shanghai Jiao Tong University form the next tier with 22 and 20 articles, respectively.

The middle range includes University of Paris Saclay (18 articles), Memorial Sloan Kettering Cancer Center and University of Michigan (both with 16 articles), University of Palermo (14 articles), and University of Pittsburgh (13 articles). Universidade de Coimbra completes the top 10 with 11 articles.

This distribution highlights the significant role of specialized cancer research centers (MD Anderson and Memorial Sloan Kettering) alongside major research universities. The international diversity of institutions—spanning North America, Europe, and Asia—indicates the global nature of research in this domain.

The substantial lead of MD Anderson (35% more publications than Utrecht) suggests its position as a focal point for research in this field. Figure 3b also reveals a stepwise decrease in publication output across institutions, with natural groupings forming at similar publication levels.

Figure 3b further highlights institutional research output through a simple yet informative format, providing clear numerical labels that facilitate precise comparisons between the different research centers. The data suggests varying institutional capacities, priorities, or resources dedicated to research publication in this field.

3.2. Citation Analysis

Figure 4 illustrates citation patterns among the most cited countries and individual documents, providing crucial insights into the academic influence and impact of different regions and key papers. Figure 4a reveals the countries with the highest citation counts, offering a measure of their global impact in this field. The United States stands out prominently, far surpassing other nations with over 3600 citations. This substantial number of citations reflects the United States’ research leadership and its ability to shape global academic discourse, which aligns with the dominance observed in earlier publication trends.

China emerges as the second most cited country, albeit with a significantly lower count than the United States which has over 1100 citations. The considerable gap between the two nations suggests that although China is growing in research output, the United States remains the leading authority. Japan, Germany, and Canada also feature prominently, reinforcing their status as research hubs with notable influence. Each of these countries has fostered active research communities contributing to the field’s development and global scholarship. The presence of several European nations and South Korea highlights a diverse geographic spread, underlining the collaborative and international nature of research (Figure 4a).

The citation analysis revealed in Figure 4b provides fascinating insights into the research that has shaped our understanding of diet and cancer treatment. Leading the citations with over 500 global references, Pierce et al.’s groundbreaking study [31] challenged conventional wisdom about diet’s role in breast cancer outcomes. Their research followed early-stage breast cancer survivors who adopted a diet extremely rich in vegetables, fruit, and fiber while maintaining low fat intake. Surprisingly, after 7.3 years of follow-up, this dietary intervention did not demonstrate the expected reduction in either additional breast cancer events or mortality rates.

Hakomori’s research [32] opened new frontiers in cancer immunotherapy by exploring tumor-associated carbohydrate antigens (TACAs) as targets for anticancer vaccines. Their clinical trials demonstrated promising results across multiple cancer types: STn vaccines showed potential for breast cancer treatment, while GM2 and GD3 proved beneficial for melanoma cases, and globo-H showed promise in treating prostate cancer. The study established crucial criteria for successful vaccine development, emphasizing the importance of high antigen expression on tumor cells and robust antibody production. While they also explored innovative approaches using idiotypic anticarbohydrate antibodies and peptide mimetics of TACAs, these methods remain in early stages of development but offer potential solutions to the challenge of weak TACA immunogenicity.

Spencer et al.’s research [33] revealed an important connection between dietary fiber and cancer immunotherapy outcomes. Their findings demonstrated that patients receiving immune checkpoint blockade (ICB) treatment showed improved progression-free survival when maintaining high fiber intake. Notably, this benefit was particularly pronounced in patients who consumed sufficient fiber while avoiding probiotic supplements, suggesting a complex interaction between diet, gut microbiota, and cancer treatment efficacy.

Giavasis [34] contributed valuable insights into the therapeutic potential of fungal compounds, particularly focusing on polysaccharides like β-glucans and heteropolysaccharides. Their research traced how these compounds evolved from traditional Asian medicine into modern pharmaceutical applications. The study highlighted these substances’ versatility in medical applications, specifically their effectiveness as antitumor agents, immune system stimulants, and prophylactic treatments. This work effectively bridged the gap between traditional medical knowledge and contemporary pharmaceutical development.

Figure 4c presents the most influential (cited) journals in dietary fiber and cancer research. Notably, the Journal of the American Medical Association (JAMA) dominates the citation landscape with 519 citations from just one paper from the dataset, demonstrating extraordinary impact. Similarly, Glycobiology and Journal of Clinical Oncology show significant influence with 424 and 402 citations, respectively.

In contrast, journals such as Cancers, International Journal of Molecular Sciences, Carbohydrate Polymers, and Frontiers in Immunology lead in publication volume, indicating their role as primary venues for ongoing research in this field (Figure 4d). Furthermore, the minimal overlap between the two panels (Figure 4c,d) suggests researchers employ different publication strategies depending on their goals. Breakthrough findings often target prestigious journals with wide readership, whereas more specialized research appears in field-specific journals.

Additionally, the diversity of journals across both panels reflects the multidisciplinary nature of using nutritional intervention including dietary fiber and cancer research, spanning from general medicine to biochemistry, oncology, and molecular sciences. Interestingly, the International Journal of Molecular Sciences appears among leaders in both metrics, suggesting its dual role as a popular venue with substantial impact.

The implication of this is significant for research strategy and scholarly communication. Researchers seeking to maximize visibility, and impact might prioritize submitting high-quality work to citation-dominant journals like Journal of the American Medical Association or Glycobiology, while those needing to build publication volume quickly might target journals like Cancers. For institutions evaluating research performance, Figure 4c demonstrates the importance of considering both metrics rather than focusing solely on publication counts. The substantial disparity between publication output and citation impact across journals also suggests fundamentally different roles within the scholarly ecosystem—some journals serve primarily as venues for disseminating new findings, while others function as platforms that significantly amplify research influence through citations.

3.3. Keyword and Topic Trend Analysis

The analysis of Figure 5 depicts the most frequent author keywords and reveals several dominant research themes. The analysis of keywords, as depicted in Figure 5a, reveals the dominant research themes in the field. ‘Dietary fiber’ emerges as the most frequent keyword with 66 occurrences (8% of total keywords), followed closely by ‘oligosaccharides’ with 64 occurrences (8%). These two major themes reflect the core focus of the research field. ‘Immunotherapy’ and ‘cancer’ represent the next tier of frequently used keywords with 38 (5%) and 37 (5%) occurrences, respectively, indicating strong research interest in therapeutic applications.

The visualization also highlights several interconnected research areas: ‘in-vitro’ (28 occurrences, 3%), ‘chain fatty-acids’ (26 occurrences, 3%), and ‘cells’ (25 occurrences, 3%) suggest significant laboratory-based experimental work. ‘Expression’ (30 occurrences, 4%) and ‘gut microbiota’ (23 occurrences, 3%) indicate a growing interest in molecular mechanisms and microbiome research. More specific disease-focused terms appear as well, such as ‘breast-cancer’ (16 occurrences, 2%), while process-oriented terms like ‘activation’ (19 occurrences, 2%), ‘apoptosis’ (17 occurrences, 2%), and ‘growth’ (17 occurrences, 2%) reflect the emphasis on understanding biological mechanisms.

3.4. Thematic Areas

The thematic map in Figure 6 divides research topics into four quadrants based on relevance and development, offering valuable insights into the maturity and impact of various themes.

In the upper-right quadrant (Motor Themes), we find “dietary fiber,” “chain fatty-acids,” and “gut microbiota.” These themes are well-developed and highly relevant, signifying their central role in shaping current research. Their positioning indicates strong development and high centrality to the field.

The upper-left quadrant (Niche Themes) features topics like “active specific immunotherapy,” “human alpha,” and “beta-cyclodextrin.” Despite their high level of development, these themes have lower relevance to the broader field. This specialized focus suggests their significance is confined to specific subfields rather than across a wide spectrum of research interests.

In the lower-left quadrant (Emerging or Declining Themes), topics like “beta-1” and “6-branched oligosaccharides” are less relevant and underdeveloped, hinting at either an emerging status or a gradual decline. Their relatively low relevance indicates that they are currently niche areas, possibly gaining traction or becoming obsolete over time.

The lower-right quadrant (Basic Themes) includes “glycosylation,” “identification,” and “binding.” These themes show high relevance but lower development, suggesting they serve as fundamental concepts underpinning more complex research areas in the field.

3.5. Evolution of Research Themes Over Time

Figure 6b illustrates the evolution of research themes over time, specifically comparing the periods of 2000–2015, 2016–2021, and 2022–2024. This visualization provides insights into how key themes have emerged, persisted, or evolved across these time frames.

In the first period (2000–2015), notable themes included “cancer,” “nanoparticles,” “dendritic cells,” “butyrate,” “inulin,” and “immunotherapy.” These topics represented a diverse range of interests, with “cancer” leading the field as a focal point. “Nanoparticles” and “dendritic cells” indicated a strong interest in innovative therapeutic delivery mechanisms and immune cell studies [35].

Moving to the next period (2016–2021), several themes persisted and evolved, while others shifted or emerged. “Cancer” remained prominent and expanded into subcategories like “colorectal cancer,” “lung cancer,” and “oral immunotherapy.” Newer themes like “microbiota” and “allergy” emerged, signifying a growing focus on the microbiome and its health implications. “Glycosylation” gained prominence, suggesting an increased interest in biochemical processes relevant to cancer research [36].

In the latest period (2022–2024), several core themes have persisted or expanded in relevance. “Immunotherapy,” “inulin,” and “gut microbiota” remain prominent, underscoring the enduring interest in immune-based treatments, carbohydrate biology, and microbiome research. Emerging themes like “dietary,” “polysaccharides,” and “cancer therapy” reflect the importance of nutritional strategies and biochemical processes in disease management. “Glycosylation,” “immunotherapy,” and “inulin” continue to play key roles, suggesting continuity in research focus [35–37].

Figure 6b effectively demonstrates how research priorities shift and evolve. Cancer-related themes have consistently remained central, with subdomains developing over the years. The rising prominence of themes like “microbiota” and “oligosaccharides” signals an expanding interest in gut health and therapeutic innovation. The persistence of topics like “immunotherapy” and “glycosylation” indicates their continued relevance across these periods. Such a diagram helps researchers identify long-standing trends and anticipate emerging directions, guiding them in strategic planning and collaboration.