EXPLORING THE IMPACT OF GUT MICROBIOTA MODULATION ON COLORECTAL CANCER THERAPY: A BIBLIOMETRIC ANALYSIS OF PROBIOTIC AND PREBIOTIC INTERVENTIONS.

INTRODUCTION
Colorectal cancer (CRC) is a common cancer that poses a major global health burden.
Globally, CRC is ranked third in terms of incidence and second in terms of
mortality, accounting for 1.8 million new cases and 881,000 deaths in 2018. Its
incidence is predicted to increase to 2.2 million new cases and 1.1 million deaths
worldwide by 2030
1
. CRC, with over 1 million new cases diagnosed annually, is the third most
prevalent type of cancer in men and the second most prevalent type of cancer in
women and the primary cause of cancer-related deaths
2
. CRC has complex causes involving both genetic and environmental
factors
1
. However, there has been a longstanding interest in the role of gut
microbiota in CRC development and progression. This curiosity is partly due to the
high microbial load in the colon and the potential involvement of the gut microbiota
in carcinogenesis.
Although microbiota colonise body surfaces, including the oral cavity, vagina, skin,
and fluids, they predominantly inhabit the gastrointestinal tract (GIT)
3
. After being acquired through vertical transmission (through birth), the gut
microbiota becomes prone to changes by environmental (external) factors such as
lifestyle, drug treatment, and diet (nutrition) and co-evolves concomitantly with
the host throughout life
4
. A disturbance in the health and stability of this ecosystem (microbial
balance) causes dysbiosis, which subsequently leads to a multitude of pathological
states, including gastrointestinal disorders, cardiovascular, respiratory,
neurological, and metabolic conditions, stomach cancer, and CRC
5
. A growing body of evidence suggests that the gut microbiota, by affecting
body metabolism, influences energy balance and glucose metabolism, and changes in
its composition are associated with the development of obesity
2
, which is a major risk factor for CRC
6
.
Interestingly, a dynamic but largely stable gut microbiota is beneficial to
health
5
. Evidence has shown that microbiota, through the production of reactive
sulphur species (RSS)
7
and short-chain fatty acids (SCFAs)
4
, enhance the host antioxidant capacity. Thus, gut microbiota may be
essential in preventing oxidative stress and its related conditions, such as cancer.
In addition, previous studies have suggested that gut microbiota modulation may be a
novel strategy for CRC prevention and treatment
1
.
Extrapolating from the above, the complex community of microorganisms residing in the
GIT (gut microbiota) may serve as a crucial novel strategy for CRC prevention and
treatment. Thus, this bibliometric analysis aimed to examine existing research
(original research articles) that reported the positive effects of modifying gut
microbiota composition with probiotics and/or prebiotics on colorectal cancer,
highlighting crucial microbial signatures.

METHODS
This study employed a systematic data selection and analysis approach to thematically
and methodologically review existing studies (original research articles) that
report positive effects of altering gut microbiota composition with probiotics
and/or prebiotics on colorectal cancer. To ensure a structured and reproducible
selection process, a structured data selection approach was implemented to identify
and categorise relevant publications systematically. However, it should be noted
that this study does not represent a systematic analysis; instead, it applied a
structured bibliometric and content analysis to evaluate the positive relationship
between gut microbiota and CRC, and research trends in the field. Ethical approval
was not required as the analysis was based on previously published data.

Literature search
This bibliometric analysis was conducted by the PRISMA (Preferred Reporting Items
for Systematic Reviews and Meta-Analyses) guidelines
8

-

9
. The literature search was conducted for research articles published
online in the English databases Google Scholar and PubMed. In this study, only
English peer-reviewed original research articles published between 2020 and 2025
were considered. To search, terms like “Colorectal Cancer” or “Colon Cancer”,
“Colorectal Carcinoma” or “Colon Carcinoma”, and “Gut Microbiota”, “Positive
Effect Gut Microbiota and Colorectal Cancer” were used. A total of 116 studies
were selected and manually reviewed. The PRISMA flow diagram detailing the
selection process is provided (Figure
1).

Inclusion and exclusion criteria
The structured search articles were considered eligible for this study if they
met the criteria:

Peer-reviewed original research articles.

Studies were in vivo.

Patients were clinically confirmed with a colon/colorectal
tumour.

Studies reported on gut microbiota composition/profile.

Studies reported a positive correlation between gut microbiota and
colorectal cancer/colon cancer.

Studies were published between 2020 and 2025.

Studies were excluded if they met the following criteria:

The same literature(s) was retrieved from the other database (no
duplication).

Reviews, meta-analyses, letters, editorial comments, conference
abstracts, case reports, overviews, paediatric articles, unpublished
articles, and non-English articles.

No control groups.

Studies published before the year 2020.

The literature(s) was not free.

Studies reported a negative correlation between gut microbiota and
colorectal cancer/colon cancer.

Literature screening and data extraction
To prevent the inclusion of duplicate papers in this work, the collected articles
were imported into Mendeley Desktop (version 1.19.8) to eliminate duplicates.
Following that, articles were screened according to the “inclusion and exclusion
criteria” of this study and irrelevant studies, such as in vitro studies, were
excluded. Finally, data extraction was systematically done and organised in a
structured Microsoft Excel spreadsheet considering the following variables:

The primary study information (year and study location).

Study subject/experimental unit information (e.g. humans/experimental
animals).

The relationship between gut microbiota and CRC (Positive
impact).

Type of probiotic and/or prebiotic used.

Sample type (e.g., fecal, intestinal tissue).

Most and least abundant microbes.

Identified taxa at the phylum, family, and genus levels

Data analysis
Data analysis and visualisation were performed using Python 3.11. The analysis
pipeline utilised open-source libraries including pandas, matplotlib, and
seaborn. The obtained results were presented using bar plots. The following
analyses were conducted:

Annual distribution of publications (2020-2025).

Geographic distribution by country.

Classification of studies by type (animal, human, combined) and
sample type.

Most and least abundant microbial taxa reported.

Taxonomic distribution at the phylum, family, and genus levels.

RESULTS

Study selection
The literature search and selection process are illustrated in FIGURE 1. In the
initial systematic search, we obtained a total of 116 studies from English
electronic databases, namely Google Scholar and PubMed. Before screening, we
excluded 30 duplicate articles. The remaining 86 articles were screened based on
their titles and abstracts, resulting in the exclusion of 23 additional
articles. Consequently, 63 articles were deemed eligible for assessment. After
reviewing the full texts of these 63 articles, we excluded 26 based on the
study’s inclusion criteria. Ultimately, 37 research articles met the study
criteria and were included in this bibliometric analysis.

Annual distribution of publications
The annual distribution of publications on probiotics and prebiotics affecting
gut microbiota from 2020 to 2025 is shown in Figure 2. Between 2020 and 2023, the number of publications
increased progressively, rising from 2020 (n=6, 16.2%) to 2022 (n=9, 24.3%) to
2023 (n=11, 29.7%). This trend suggests a growing academic interest in
interventions that aim to modify the microbiota. However, it is interesting to
note that the year 2021 also exhibited a modest decline in publications (n=3,
8.1%), which may be indicative of transient fluctuations in research output or
reporting. Also, a notable decrease in publication volume is observed in the
following years, with only 5 publications in 2024 (13.5%) and 3 in 2025 (8.1%).
This decline may be attributed to several factors: a possible stabilisation of
research output in the field, a shift toward more specialised or mechanistic
studies, or a time lag in indexing recent literature, especially for 2025.
Notably, the year 2025 saw a lower number of publications, with just three,
which could reflect a temporary dip in research activity.

Distribution of studies by country
The geographical distribution of studies examining the effects of probiotics
and/or prebiotics on gut microbiota is illustrated in Figure 3. A clear dominance by a few countries is evident,
reflecting regional trends in research productivity and investment in microbiome
science.

China is the leading contributor with 22 publications, making up a significant
portion of the total dataset (59.5%). This strong position can be attributed to
the country’s growing scientific output, increased governmental support for
health-related biotechnology, and a strategic focus on gut microbiota research
in recent years. China’s interest in functional foods, traditional medicine, and
dietary modulation likely supports this trend.
The United States ranks second with 5 publications (13.5%), reflecting its strong
research infrastructure and its established contributions to nutrition and
microbiome science. However, its output on this specific topic seems modest
compared to China, which may indicate that the U.S. has more diversified
research priorities.
Several other countries, including South Korea (3 publications, 8.1%), Japan,
Taiwan, Canada, the United Arab Emirates, and Italy (each contributing 1
publication, 2.7% respectively). This varied involvement indicates a rising, yet
still limited, global interest in probiotic and/or prebiotic-related microbiota
research beyond the leading nations.

Study type distribution based on experimental units

Figure 4 shows the classification of the
included studies based on their subject units. An analysis of the distribution
of study types among the 37 unique articles revealed a strong predominance of
animal-based research. Specifically, 31 studies (83.8%) focused exclusively on
animals, indicating a significant reliance on preclinical models in probiotic
and prebiotic research. In contrast, only 3 articles (8.1%) were based on human
subjects, and another 3 articles (8.1%) incorporated data from both animal and
human sources. This distribution highlights a significant gap between
experimental research and clinical application in this field. The low percentage
of studies involving humans and translational research indicates that, despite
the growing interest in microbiome modulation, the scientific literature
continues to depend heavily on animal models for investigating gut microbial
dynamics and host responses. The lack of combined studies involving both animals
and humans highlights the limited efforts to verify findings from animal
research in human populations. This validation is crucial for connecting
laboratory results with clinical applications. These observations underscore the
necessity for future research to broaden the representation of human cohorts and
to encourage integrative designs that allow for comparisons across species. Such
methods could improve the external validity of microbiome research and aid in
the development of targeted dietary or therapeutic interventions that have
proven effective in human subjects.

Biological sample types

Figure 5 illustrates the distribution of
biological sample types used in studies that evaluate the impact of probiotics
and/or prebiotics on gut microbiota composition. Among the 37 unique studies
included in this analysis, a clear methodological trend was observed regarding
the biological sample types utilised for microbiota profiling. Faecal samples
were used in 35 studies (94.6%), making them the most commonly adopted sample
type. One study (2.7%) utilised a combination of faecal and colonic tissue
samples, while another study (2.7%) did not specify the sample type used. The
predominance of faecal sampling highlights its methodological advantages,
including non-invasiveness, ease of collection, and suitability for both animal
and human research. The limited use of colonic tissue samples underscores the
challenges associated with invasive procedures, particularly in human
studies.

Classification of studies based on mode of microbiota modification

Figure 6 presents the classification of 37
unique studies based on their use of probiotics, prebiotics, or a combination of
both. The data indicate a significant predominance of prebiotic-focused
interventions in the literature. Among the included studies, 26 studies (70.3%)
utilised prebiotics exclusively, while 9 studies (24.3%) concentrated solely on
probiotics. Only 1 study (2.7%) employed a combined approach that incorporated
both probiotics and prebiotics, known as a synbiotic design. Additionally,
another study (2.7%) did not clearly define the type of intervention used. This
distribution suggests that prebiotics have been more frequently researched,
likely due to their easier formulation, more consistent regulatory status, and
broader dietary applications. In contrast, the studies focusing solely on
probiotics were less common, and the use of combined approaches remains
underrepresented, even with the growing interest in synbiotic therapies. The
limited number of studies investigating combined interventions may reflect
challenges related to study design, safety concerns, or difficulties in
understanding the underlying mechanisms. Nonetheless, this trend highlights a
significant opportunity for future research to explore the synergistic effects
of probiotics and prebiotics on gut microbiota composition and overall host
health outcomes.

Types of probiotics used in studies

Figure 7 illustrates the classification of
probiotics used in the studies analysed. Among the 9 studies that used
probiotics as the sole intervention, specific probiotic strains were reported in
seven studies. Clostridium butyricum was the most frequently
used species, appearing in two studies (22.2%). Each of the following probiotic
types was reported in one study (11.1% each): lactobacillus
gallinarum, Lactobacillus plantarum,
Parvimonas micra, Bifidobacterium
fragilis, Bifidobacterium lactis, Pediococcus
pentosaceus and an undefined “probiotic powder.” In addition to
Clostridium butyricum, Lactobacillus spp.
(Lactobacillus gallinarum and Lactobacillus
plantarum) and Bifidobacterium spp.
(Bifidobacterium fragilis and Bifidobacterium
lactis) were reported in two studies each, making them also the
most frequently used species.

Types of prebiotics used in studies

Figure 8 illustrates the distribution of
prebiotic classifications among the studies included in this analysis. A
significant finding is the clear dominance of the “Natural compounds and
extracts” category, which comprises more than half of the classified studies
(n=14, 53.8%). This category encompasses a diverse array of plant-based
substances, herbal decoctions, polysaccharides, and other bioactive dietary
components. In contrast, a smaller group of studies utilised “Not commercial”
prebiotics (n=8, 30.8%), referring to experimental or naturally derived
substances that are not associated with any specific commercial formulation.
Pharmaceutical agents, such as antibiotics, antidiabetic drugs, or inhibitors,
were examined in 4 studies (15.4%). These findings highlight a relatively high
level of reporting rigour for prebiotic interventions.

Frequently identified microbial phyla

Figure 9 summarises the 10 most frequently
identified microbial phyla across studies examining the impact of probiotics
and/or prebiotics on gut microbiota composition. The taxonomic data were
standardised to account for synonymous classifications (e.g.,
Verrucomicrobia and Verrucomicrobiota were
combined). The phylum Firmicutes was the most commonly
reported, appearing in 48 studies. This dominance is consistent with its known
abundance in the gastrointestinal tract and its central role in fermenting
dietary fibres, producing short-chain fatty acids, and influencing host energy
balance.

Following Firmicutes, the phyla Bacteroidetes
(in 41 studies) and Verrucomicrobia/Verrucomicrobiota (appeared
in 12 studies, if merged) were also frequently reported, reflecting their
well-established importance in gut ecology and health. Other phyla, such as
Proteobacteria, Actinobacteria, and
Nitrospirota, were observed less frequently, suggesting
more targeted or niche-focused investigations.

Frequently identified microbial families

Figure 10 shows the ten most commonly
identified microbial families in studies exploring the effects of probiotics
and/or prebiotics on gut microbiota. The data highlight a prevalence of findings
related to bacterial families that are typically associated with gut health,
energy metabolism, and interactions between hosts and microbes. The most
frequently reported family is Lactobacillaceae, accounting for
24.5% (n=26), which aligns with the widespread use of Lactobacillus
species in probiotic products. Members of this family are
well-known for their roles in maintaining the integrity of the mucosal barrier,
modulating immune responses, and producing antimicrobial compounds like
bacteriocins. Bacteroidaceae was the second most prevalent,
accounting for 11.3% (n=12).

Following closely in frequency are Rikenellaceae (10.4%, n=11)
and Akkermansiaceae (9.4%, n=10). Akkermansia
muciniphila, a key representative of the
Akkermansiaceae family, has gained significant attention
for its role in mucin degradation and its potential anti-obesity and
anti-diabetic properties. Other families, including
Odoribacteraceae (7.5%), Lactobacillaceae
and Bifidobacteriaceae (5.7% each), were also present at
moderate frequencies and are commonly associated with probiotic functions.

Ruminococcaceae and Clostridiaceae each
accounted for 4.7%, along with Prevotellaceae (3.8%)
constituted the top ten, thereby emphasising the taxonomic diversity of the
microbial communities evaluated across the included studies. The distribution of
taxa reflects both core gut microbiota members and taxa of emerging interest in
the field of microbiome research.

Frequently identified microbial genera

Figure 11 shows the ten most frequently
identified microbial genera in studies examining the effects of probiotics
and/or prebiotics on gut microbiota. Unlike ranking dominance or suppression
within individual studies, this distribution reflects the overall frequency of
each genus reported in the literature, providing insights into the most commonly
targeted or observed microbial groups.

The genus Bacteroides ranked highest, appearing in 2.4% (n=12).
As a core component of the human gut microbiota, Bacteroides
species play critical roles in breaking down complex
polysaccharides, modulating the host immune system, and producing short-chain
fatty acids (SCFAs). Their prevalence in scientific literature may be due to
their sensitivity to dietary interventions and their role as indicators of
microbiota functionality and composition.

Alistipes and Parabacteroides, both members of
the Bacteroidetes phylum, were also frequently reported in 2.0%
(n=10) of entries. Alistipes is increasingly associated with
stress, inflammation, and disease states when dysregulated, while
Parabacteroides has been studied for its potential
anti-inflammatory and metabolic roles. Their repeated identification suggests a
dual role in both beneficial and dysbiotic gut environments, depending on the
context.
Key members of the Firmicutes phylum, such as
Lachnospiraceae and Ruminococcus, were
also prominently featured, each appeared in 1.8% (n=9) of enteries. These genera
are major producers of butyrate, essential for maintaining epithelial integrity
and modulating host metabolism. The presence of Akkermansia
(1.8%, n=9) of entries, particularly the species A.
muciniphila, further highlights its emerging significance, as it is
linked to mucin turnover and metabolic health benefits.
Other frequently reported genera include Odoribacter and
Turicibacter (1.6%, n 8 each), which are typically
categorised as low-abundance but functionally significant taxa. These genera
have been implicated in various host physiological processes, especially lipid
metabolism and gut motility. Additionally, Roseburia is noted
in 1.4% (n=7) of entries, a prominent butyrate-producing genus, has been
recognised for its role in anti-inflammatory pathways and glucose homeostasis.
Lastly, Lactobacillus appeared in 1.6% (n=8) of entries, a
well-established and widely used probiotic genus, which is commonly included in
commercial formulations due to its ability to restore microbial balance and
support mucosal immune function.

Most abundant microorganisms in individual studies

Figure 12 presents the microbial taxa most
frequently reported as the dominant (most abundant) organisms within individual
studies. Instead of showing overall abundance across pooled datasets, this graph
highlights the specific taxa recognised as the most prominent in relative
abundance for each study context. The genus Akkermansia was the
most frequently cited as the dominant microbe, being reported as the
highest-abundance taxon in six separate studies. This aligns with the growing
interest in Akkermansia muciniphila, due to its mucin-degrading
properties and beneficial metabolic associations, including improved glucose
tolerance and anti-inflammatory effects.

Other genera or families commonly identified as dominant in studies included
Lachnospiraceae, Lactobacillus, and
Bifidobacterium. These taxa are well-known for their roles
in the production of short-chain fatty acids, maintenance of gut barrier
integrity, and regulation of the host immune system. The presence of
Ruminococcaceae, Clostridium, and
Bacteroides further emphasises their ecological importance
and responsiveness to prebiotic or probiotic interventions.
Interestingly, taxa such as Bifidobacterium animalis,
Akkermansia muciniphila, and
Muribaculaceae, while not universally dominant, were noted
as peak-abundance organisms within individual studies. This indicates their
potential for context-dependent expansion under certain experimental
conditions.

Least abundant microorganisms in individual studies

Figure 13 displays the microbial taxa that
were most frequently reported as having low abundance in individual studies. It
is important to note that this does not indicate overall low abundance across
all samples; rather, it reflects which taxa were identified as the least
dominant within specific experimental or observational contexts. The genus
Alistipes was the most commonly reported low-abundance
taxon, identified as the least represented organism in six studies. Although
Alistipes is a common gut commensal, its low abundance may
indicate sensitivity to specific probiotic or prebiotic interventions or
associations with compromised ecological niches within the microbiota.

Other taxa frequently identified as having low abundance include
Bacteroides, Odoribacter, and
Turicibacter. Although these genera are often abundant in
healthy individuals, they may experience significant reductions under certain
dietary conditions, during inflammation-driven dysbiosis, or as a result of
targeted microbial modulation strategies.
Additionally, Streptococcus, Helicobacter, and
Desulfovibrio appeared among the least abundant taxa.
Helicobacter and Desulfovibrio are
particularly noteworthy due to their potential pathogenicity and their links to
mucosal inflammation and sulfur metabolism, respectively. Their low abundance in
many studies may reflect intentional suppression or baseline scarcity in healthy
models.
Finally, the presence of Lachnospiraceae and
Parabacteroides on this list, despite their common
identification as beneficial or butyrate-producing organisms, suggests
context-dependent depletion, such as during fibre-restricted diets or high-fat
feeding regimens.

DISCUSSION
The primary risk factors for CRC include advanced age and genetic and environmental
factors
1
. Despite this, there has been significant interest in the role of gut
microbiota in the development and progression of CRC. This interest is probably a
result of the high load of microbes in the colon and the implication of the gut
microbiota in carcinogenesis. The gut microbiota is the largest and most influential
microecosystem in the body and plays a pivotal role in maintaining overall
health
10
. Currently, standard therapies for CRC include immunotherapy,
chemoradiotherapy, and surgery, all of which are associated with recurrence,
metastasis, and poor prognosis
10
. This highlights the need for alternative treatment strategies. One
promising treatment approach is the modulation of the gut microbiota using natural
compounds or extracts, such as Huangqin Decoction
10
. Research has shown that by modulating the gut microbiota, the therapeutic
impact of 5-fluorouracil (5-FU), a drug commonly used to treat gastrointestinal
tumours, is enhanced while mitigating its side effects. Thus, the modulation of gut
microbiota plays an essential role in the treatment of CRC and has been recognised
as a promising mechanism for the treatment of CRC
11
.
In this bibliometric analysis, 37 publications were examined. China emerged as the
leading contributor, with 22 publications accounting for 59.5% of the dataset. This
prominence can be attributed to the country’s increasing investment in scientific
research and its interest in traditional medicine. In this study, a marked
preference for using prebiotics and/or natural compounds (such as extracts) to
modulate the gut microbiota was observed, as most of the publications from China
focused on Traditional Chinese Medicine
10

-

20
. Among the 37 studies analysed, 70.3% focused solely on prebiotics, 24.3%
used probiotics, and only 2.7% adopted a combined approach (probiotics and
prebiotics). This indicates that the preferred mode of modifying the gut microbiota
is distinctly dominated by prebiotics, products derived from dietary fibres, or
plant compounds that are easier to integrate into functional foods
21

,

22
.
In contrast, the use of probiotics, which involves the administration of live
microorganisms, faces various challenges, such as species-specific efficacy,
variability in responses among individuals, and difficulties in transportation and
storage conditions
23

,

24
. These challenges may have led to a lesser representation of probiotic
studies in the literature. Although the combined use of prebiotics and probiotics
could theoretically exhibit synergistic effects by enhancing microbial viability and
supporting targeted metabolic activities, factors such as the selection of
compatible probiotic strains and appropriate prebiotic substrates complicate the use
of this approach. Nevertheless, the use of well-designed combinations can contribute
to the development of more effective therapeutic strategies for managing diseases
associated with dysbiosis
25
.
The classification of prebiotic types used in studies revealed a distinct trend
towards natural compounds and plant-derived bioactive substances. More than half of
the prebiotic interventions (53.8%) consisted of natural extracts, herbal
ingredients, and dietary polysaccharides. This reflects the interest in the effects
of traditional medicine and functional foods on the gut microbiota, particularly in
Asian countries
26
.
Considering the annual distribution of publications, this study reports a decline in
publications on this subject, as 2025 contributed only three publications to the
dataset (8.1%). This could mean that research on the subject is shifting to more
specialised studies, such as the use of non-commercial or experimental prebiotics.
The use of non-commercial or experimental prebiotics (30.8%) indicates that
microbiota research is still in its exploratory phase. This group includes new
oligosaccharides or unidentified fibre complexes, and the prebiotic potential of
these components has not yet been definitively established. While this provides
scientific innovation, it can also lead to variability in the results due to
differences in content and dosage. The analysis of probiotic species used in studies
has been noteworthy in terms of microbial diversity, but it has revealed that the
number of probiotic-focused interventions remains limited. Clostridium
butyricum was the most commonly used species, appearing in two of the
nine studies (22.2%). Additionally, species from the Lactobacillus
and Bifidobacterium genera were included in two studies each,
demonstrating that these groups are important in probiotic research
24

,

26
.
Xue et al.
17
reported Firmicutes and Bacteroidetes as
the most dominant phyla, consistent with the trend of a higher frequency of
Firmicutes, followed by Bacteroidetes,
observed in the studies included in this analysis. This trend is likely because
these phyla are the most abundant microbes in the gut, as species from the phyla
Bacteroidetes and Firmicutes account for over
90% of the gut microbiota
10
. At the genus level, Akkermansia spp. was the most
frequently cited dominant microbe (most abundant). This is probably due to its
ability to inhibit the occurrence of colonic tumours and ensure intestinal
epithelial barrier integrity by exhibiting protective effects to reduce mucosal
inflammation that may have been induced by colitis or CRC
11
. Following Akkermansia, Lachnospiraceae
was the most abundant beneficial bacterium in a healthy gut
10
.
When evaluated from the perspective of experimental design, animal models have stood
out in studies examining the effects of probiotics and prebiotics on the gut
microbiota and host physiology. Of the 37 articles assessed, 83.8% were based solely
on animal subjects, 8.1% were based on human subjects, and 8.1% included both human
and animal data. Although experimental animal models are often preferred because of
their relatively low cost, ease of manipulation, and controllable experimental
environments, their direct applicability to human physiology presents a significant
limitation
28

,

29
. Differences in metabolic pathways, immune responses, and microbial loads
among species make it difficult to translate data obtained from experimental models
to humans directly
27

-

28

,

30
. Therefore, the increasing importance of studies that include both animal
and human data is crucial for validating the findings obtained and establishing a
solid foundation for clinical applications. Walter et al.
31
stated that inter-species comparative designs are critical for understanding
independent microbiome responses and optimising interventions specific to human
health.
In studies evaluating the effects of probiotics and/or prebiotics on the gut
microbiota, a distinct methodological trend towards using faecal samples appears.
The fact that faecal samples were used in 94.6% of the 37 analysed studies shows
that this sample type has become the standard for microbiota profiling. This finding
is consistent with existing trends in the literature, as faecal sampling is
considered a practical, noninvasive, and repeatable method for both human and animal
studies
32

,

33
.

CONCLUSION
In conclusion, the relationship between gut microbiota and colorectal cancer (CRC)
highlights the complexity and significance of microbial communities in health and
disease. While certain taxa demonstrate context-dependent abundance variations, the
modulation of gut microbiota through natural compounds, particularly prebiotics,
shows promise as a complementary strategy in CRC treatment. The predominance of
studies focused on prebiotics, especially from China, indicates a growing interest
in leveraging traditional medicine and dietary approaches for enhancing therapeutic
outcomes. While challenges remain in the use of probiotics, exploring the
synergistic effects of combined prebiotic and probiotic interventions could pave the
way for more effective CRC management strategies. However, further research is
essential to deepen our understanding of gut microbiota dynamics and to optimise
therapeutic approaches for CRC patients.