Gastrointestinal cancers, which include cancers of the oesophagus, stomach, pancreas, liver, biliary tract, small intestine, colon and rectum, are among the most common causes of cancer-related illness and death worldwide [27-30]. These cancers affect organs that are directly involved in digestion and absorption of nutrients, so patients are particularly vulnerable to malnutrition. Many observational studies have reported that 40-80% of GI cancer patients already have weight loss, poor appetite, early satiety, dysphagia, nausea or diarrhoea by the time they are diagnosed [9,14,27-31].

Malnutrition in cancer is not just a simple problem of low body weight. It is a complex state that involves changes in body composition, reduced food intake and metabolic alterations driven by the tumour and systemic inflammation [1,2,32]. Cancer-associated malnutrition and cachexia can lead to loss of skeletal muscle, weakness, fatigue, impaired immune function, delayed wound healing and reduced quality of life [21,30,32-35].

Chemotherapy, which is one of the main treatment options for GI cancers, can further worsen nutritional status. Common chemotherapy-related side effects such as nausea, vomiting, mucositis, diarrhoea, taste changes and anorexia reduce oral intake, while systemic inflammation and tissue repair increase metabolic demands [5,6,18,19]. These factors together can accelerate weight loss and muscle wasting during treatment, and several cohort studies have shown rapid decline in weight and muscle mass during the first few cycles of chemotherapy in GI cancer patients [15,17-19,22,36].

Nutritional status is clinically important because it influences how patients tolerate chemotherapy and how well they respond to it. Poor nutritional status has been linked to more frequent and severe ADRs, dose delays, dose reductions and even early discontinuation of treatment [3,16,18-21]. In addition, malnutrition is associated with higher rates of infection, longer hospital stays, decreased functional status and poorer survival [9,10,20-22,37-40]^. On the other hand, patients who are better nourished tend to have fewer complications, are more likely to receive planned chemotherapy dose intensity, and may achieve better tumour response [3,11-13,18,22].

Several tools have been developed to assess nutrition in cancer patients. The Patient-Generated Subjective Global Assessment (PG-SGA) is widely used and considered a reference method in oncology.11,34,35,40^.The Global Leadership Initiative on Malnutrition (GLIM) has proposed diagnostic criteria that combine phenotypic features such as weight loss, low body mass index (BMI) or reduced muscle mass with etiologic factors such as reduced intake or inflammation [32,41]. Screening tools such as the Malnutrition Universal Screening Tool (MUST) help identify patients at risk, while indices like the Prognostic Nutritional Index (PNI), which uses serum albumin and lymphocyte count, provide prognostic information [9,10,16,19,23].

Despite strong evidence and international guidelines stressing the importance of nutritional care in cancer, nutritional assessment is still not consistently implemented in daily oncology practice [1,2,31,33]. Many patients are not screened at baseline, and nutrition interventions may be delayed or insufficient. There is a need to clearly summarise and present the existing evidence linking nutritional status to chemotherapy response and ADRs specifically in GI cancers, to support stronger integration of nutrition into cancer care [3,16,18-22].

This systematic review therefore focuses on GI cancers, where the burden of malnutrition is particularly high, and explores how baseline and evolving nutritional status affects chemotherapy outcomes and toxicity. The findings can help clinicians, pharmacists and dietitians to identify high-risk patients early and to plan timely interventions to improve both safety and efficacy of treatment [9,14,18,19,22,27-30].

Gastrointestinal Cancers and Malnutrition

Prevalence of Malnutrition in GI Cancers

Malnutrition is highly prevalent in GI cancers compared to many other tumour types. Because the tumour often affects organs involved in eating and digestion, symptoms such as dysphagia, early satiety, abdominal pain, nausea, vomiting, malabsorption and diarrhoea are common [27-29,31-34]. Many observational studies have found that 40-80% of GI cancer patients are malnourished or at risk at the time of their first oncology visit [9,14,27-30,36-40].

Studies using tools like PG-SGA or GLIM frequently report that more than half of patients have moderate or severe nutritional impairment even before chemotherapy starts [11,14,15,34,40,41].  Weight loss of more than 5-10% in the previous 3-6 months is also very common [9,14,27-30].  These findings show that malnutrition is not a rare complication but a central feature of GI cancer.

Mechanisms of Cancer-Related Malnutrition

Several mechanisms contribute to malnutrition in GI cancers:

• Reduced Intake: Pain, dysphagia, nausea, taste changes, early satiety and depression reduce food intake [ 27-29,31].
• Malabsorption: Tumours or treatment affecting the stomach, small bowel or pancreas can interfere with digestion and absorption of nutrients [28,29,32].
• Increased Metabolic Demands: Systemic inflammation driven by the tumour increases resting energy expenditure and protein breakdown [1,2,21,32].
• Altered Metabolism: There may be changes in how carbohydrates, fats and proteins are used, promoting muscle loss [32-35].
• Cancer Cachexia: This is a complex syndrome involving muscle wasting that is not fully reversed by normal feeding, driven by inflammatory cytokines and hormonal changes [21,32-35].

These factors together result in loss of fat mass, loss of muscle mass (sarcopenia) and general weakness [30,32-35].

Clinical Consequences

Malnutrition has many negative consequences for GI cancer patients:

• Reduced physical function and performance status [9,30,33].
• Increased risk of infections and poor wound healing [20-22,35].
• Higher rates of treatment-related complications, including severe haematological and gastrointestinal toxicities [16,18-21].
• Longer hospital stay and more frequent readmissions [6,20-22,37-39].
• Lower quality of life and emotional well-being [11-13,22,31].
• Higher mortality and poorer progression-free survival [9,10,19-22,40].

Because chemotherapy is a demanding treatment both physically and mentally, patients who start therapy in a malnourished state are at a clear disadvantage [3,16,18-22].

Nutritional Assessment Tools in GI Cancer Patients

Proper identification of malnutrition and nutritional risk is the first step towards effective nutritional care. Several tools are available, and many studies have evaluated their use in GI cancer [1,2,9-11,32,34,40,41].

Malnutrition Universal Screening Tool (Must)

MUST is a simple screening tool that combines BMI, percentage of unintentional weight loss and the presence of acute disease that has caused little or no intake for more than five days. Each component receives a score, and the sum categorises patients into low, medium or high risk of malnutrition [1,2,32].

In GI cancer, MUST is useful as a quick screening method at admission or first oncology visit [27-30,36-39]. However, it does not include detailed symptoms or functional status and is not cancer-specific. Therefore, positive screening with MUST should be followed by a more detailed assessment such as PG-SGA or GLIM [11,32,34,40,41].

Patient-Generated Subjective Global Assessment (PG-SGA)

PG-SGA is an extension of the original Subjective Global Assessment, adapted for cancer patients. It consists of a patient part and a clinician part. The patient reports weight changes, food intake, symptoms affecting nutrition (such as nausea, vomiting, mouth sores, constipation, diarrhoea, loss of appetite) and activity level, while the clinician assesses muscle mass, fat stores, oedema and physical findings [11,34,35,40].

A global rating (A, B or C) classifies the patient as well nourished, moderately malnourished or severely malnourished. In addition, a numerical score helps guide urgency of intervention. PG-SGA is considered one of the best tools in oncology because it captures both subjective and objective aspects and has been validated in many cancer populations, including GI cancer and patients undergoing chemotherapy [11,15,34,35,40].

Global Leadership Initiative on Malnutrition (GLIM) criteria

GLIM criteria were developed to standardise the diagnosis of malnutrition globally [32,41]. Diagnosis requires at least one phenotypic criterion plus one etiologic criterion.

Phenotypic criteria include:

• Non-volitional weight loss beyond defined cut-offs
• Low BMI adjusted for age
• Reduced muscle mass
• Etiologic criteria include:
• Reduced food intake or assimilation
• Inflammation or disease burden

GI cancer clearly fulfils the inflammation/disease burden component, and many patients also meet criteria for weight loss or low BMI [27-30,32,34]. GLIM helps not only to detect malnutrition but also to classify its severity (moderate or severe), which is useful for risk stratification in chemotherapy patients [32,34,40,41].

Prognostic Nutritional Index (PNI)

PNI is a simple index calculated from serum albumin and total lymphocyte count. It reflects both protein reserves and immune function [9,10,16,19,23]. Lower PNI values indicate worse nutritional and immunological status.

Several studies in GI cancers, especially gastric and colorectal cancers, have shown that low PNI before treatment is associated with higher postoperative complications, more chemotherapy-related toxicity and poorer survival [9,10,16,19,23]. PNI is easy to calculate from routine blood tests and is therefore attractive in busy clinical settings.

Other Indicators

Other commonly used nutritional indicators include:

• BMI -easy to measure but may not reflect muscle loss [27-30].
• Percentage Weight Loss - sensitive to recent changes and an important sign of risk [9,14,27-30].
• Albumin - reflects protein status but is also affected by inflammation and hydration [16,19,23,32].
• Sarcopenia Measurement using CT scans or bioimpedance - more precise but requires specific resources [30,32-35,42].

In practice, a combination of screening tools (like MUST), diagnostic criteria (GLIM), functional assessments (PG-SGA) and biochemical indices (PNI, albumin) gives the best picture of the patient’s status and risk [1,2,9-11,16,32,34,40].

Impact of Nutritional Status on Chemotherapy Response

Influence on Drug Handling and Pharmacokinetics

Nutritional status can affect how chemotherapy drugs are distributed, metabolised and cleared from the body. For example:

• Low albumin levels can increase the free (unbound) fraction of highly protein-bound drugs, potentially increasing toxicity [16,19,23].
• Reduced muscle mass may alter the volume of distribution and drug clearance [3,18,21,30,32].
• Liver and kidney function may be impaired in severely malnourished patients, affecting drug metabolism and excretion [16,19,23,32].

These changes may reduce the therapeutic window and increase the risk of adverse effects at standard doses [3,16,18-21].

Dose Intensity and Treatment Continuity

A key concept in chemotherapy is “dose intensity”, which refers to the amount of drug delivered over time. Several studies, including large multicentre analyses in GI malignancies, have shown that patients who are malnourished at baseline are less likely to receive the planned dose intensity [3,15,18-21]. They more often require dose reductions, cycle delays or early discontinuation due to toxicity, infection or poor performance status [3,16,18-21,37-39].

In contrast, patients with better nutritional status are more likely to complete planned cycles and maintain dose intensity, which can translate into better tumour control [3,11-13,18,22,26].

Response According To RECIST and Survival Outcomes

Response to chemotherapy is often measured using RECIST 1.1 criteria (Complete Response, Partial Response, Stable Disease, Progressive Disease). Evidence from various GI cancer studies suggests that:

• Well-nourished or low-risk patients have higher rates of complete or partial response [3,10,11,18,22].
• Malnourished patients have higher rates of stable disease or progressive disease [3,9,10,18-22].

Moreover, nutritional status has been repeatedly linked with survival. Malnutrition defined by PG-SGA, GLIM or significant weight loss is associated with worse overall survival and progression-free survival [9,10,19-22,30,40]. Some meta-analyses show that moderate to severe malnutrition can double the risk of death compared with well-nourished patients [30,40,42].

These findings underline that nutritional status is not just a background factor but a strong prognostic and predictive marker in GI cancer chemotherapy [3,9,10,18-22,30].

Nutritional Status and Chemotherapy-Induced Adverse Drug Reaction

Common Toxicities in GI Cancer Chemotherapy

Chemotherapy regimens used for GI cancers, such as FOLFOX, FOLFIRI, capecitabine-based combinations, platinum agents and taxanes, are associated with a range of ADRs. Common toxicities include:

• Haematological: neutropenia, anaemia, thrombocytopenia
• Gastrointestinal: nausea, vomiting, diarrhoea, constipation, mucositis
• Neurological: peripheral neuropathy
• Constitutional: fatigue, anorexia, weight loss

These toxicities are usually graded using the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0, from grade 1 (mild) to grade 5 (death) [16,18-21,25].

Relationship between Malnutrition and Toxicity

Many studies have reported that malnourished patients, or those with low albumin, low PNI or high PG-SGA scores, are at higher risk of severe (grade 3-4) toxicities [16,18-21,23,25].

Possible reasons include:

• Reduced physiological reserve, making it harder to tolerate myelosuppression or fluid loss
• Impaired mucosal integrity, leading to more severe mucositis and diarrhoea
• Weakened immunity, predisposing to infections during neutropenia
• Altered drug binding and metabolism, as discussed earlier [16,19,23,32].

Some studies specifically show that low baseline albumin predicts severe neutropenia, and that higher PG-SGA scores are associated with more frequent gastrointestinal toxicities [16,18–21,23-25]. Nutritional risk scores have also been linked to the need for unplanned hospitalisations due to toxicity [6,18-21,37-39].

Causality and Severity Assessment

While CTCAE is used to grade severity, ADR causality can be evaluated using scales such as the Naranjo algorithm. Severity in terms of clinical impact (e.g., requirement for hospitalisation, intensive care, permanent harm) can be assessed by the Hartwig and Siegel severity assessment scale [24,25].

From a nutritional perspective, these tools help to systematically document how often serious ADRs occur in different nutritional risk groups. Several observational studies have used this approach to show that higher nutritional risk categories have a greater proportion of “probable” ADRs and more severe grades [16,18-21,23-25].

Evidence from Clinical Studies: Summary

Across the included research articles, several main categories can be identified:

1. Guidelines and Expert Consensus on Clinical Nutrition in Cancer, which strongly recommend early screening and intervention [1,2,32,41].
2. Observational Studies that document the prevalence of malnutrition in GI cancers and its impact on outcomes [6,9,14,15,27-30,34,36-40].
3. Studies Linking Specific Tools (PG-SGA, GLIM, PNI, MUST) with chemotherapy tolerance and survival [3,9-11,16,19,23,32,34,40,41].
4. Randomised Trials or Controlled Studies evaluating the effect of oral nutritional supplements or diet counselling during chemo [4,5,7,8,11-13,22,26].
5. Systematic Reviews and Meta-Analyses summarising nutritional interventions and their benefits [2,30,40,42].

Overall, the evidence shows a consistent pattern: worse nutritional status is associated with more complications and poorer outcomes, while nutrition support can help maintain or improve tolerance and sometimes clinical results [3,5-8,11-13,18-22,26,30,40-42].

Nutritional Support and Interventions

Oral Nutritional Supplements (ONS)

ONS are energy-dense and protein-rich drinks or powders designed to increase nutrient intake when patients cannot meet their needs through normal food alone. Randomised trials and meta-analyses in GI cancer patients receiving chemotherapy have shown that ONS can:

• Help stabilise or slightly increase weight
• Improve nutritional markers such as albumin or PNI
• Reduce unplanned treatment interruptions
• Improve some quality-of-life scores [4,5,7,8,11-13,22,26].

ONS are especially useful in patients with poor appetite, early satiety or mild dysphagia [4,5,7,28,29].

Enteral and Parenteral Nutrition

When oral intake is insufficient or impossible (for example due to severe dysphagia, bowel obstruction or very severe mucositis), enteral nutrition via feeding tubes (nasogastric, gastrostomy or jejunostomy) or parenteral nutrition via intravenous routes may be necessary [28,29,32,33].

These approaches can prevent severe weight loss and help patients complete planned chemotherapy, but also carry risks such as infection, refeeding syndrome or metabolic complications. Therefore, they should be used under specialist supervision [28,29,32].

Dietary Counselling and Education

Individualised diet counselling by a clinical dietitian is an important part of care. It includes:

• Assessing current intake and problems
• Suggesting food modifications, meal frequency changes and symptom-targeted strategies
• Educating patients and families about high-calorie, high-protein options and safe food handling

Randomised and quasi-experimental studies show that structured counselling can improve intake, reduce weight loss and sometimes reduce chemotherapy-related gastrointestinal toxicities [7,11-13,22,26,31].

Prehabilitation and Exercise

Prehabilitation refers to interventions performed before starting major treatment, such as chemotherapy or surgery, to build up the patient’s reserves. It may combine nutrition support, physical exercise and psychological support.

In GI cancers, prehabilitation programmes have shown promise in improving functional capacity, protecting muscle mass and enhancing the ability to complete planned treatment [4,22,30,42]. More research is still needed, but early results are encouraging.

Across the collection of research articles in your spreadsheet, one major theme repeatedly emerges: malnutrition and nutritional risk are extremely common in gastrointestinal cancer patients, often present even before chemotherapy begins [6,9,14,15,27-30,34,36-40]. The literature clearly demonstrates that nutritional status is not simply a background factor but a powerful predictor of treatment tolerance, recovery, survival, and overall well-being. Poor nutritional status increases the likelihood of dose delays, reductions, early termination of therapy, and higher severity of side effects [3,16,18-22,30,40].

Many studies show that unintentional weight loss, low muscle mass, reduced dietary intake, and low albumin or composite nutritional indices such as PNI and GNRI strongly correlate with poorer clinical outcomes [9,10,16,19,21,23,30,40,42]. Another important message is that nutrition screening must be systematic and performed early, using validated tools like PG-SGA, MUST, NRS-2002 or GLIM, rather than relying on weight or BMI alone [1,2,11,32,34,40,41].

Research emphasises that malnutrition in GI cancers is driven by multiple factors including tumour location, disease stage, symptom burden, inflammation, and cancer cachexia [21,27-30,32-35]. Early dietary counselling and oral nutritional supplements were shown to improve energy intake, stabilise body weight, enhance functional status, and support better tolerance to anticancer treatments [4,5,7,8,11-13,22,26]. Evidence suggests that a multidisciplinary approach involving oncologists, surgeons, dietitians, nurses, and physiotherapists leads to improved supportive care and patient outcomes [1,2,22,31-33].

Several articles highlight specific challenges in upper GI cancers, where swallowing difficulty, obstruction, or malabsorption quickly worsen nutritional status[28,29,31-34]. Others stress that nutrition care usually starts too late in real-world practice, with interventions beginning only after severe weight loss has already occurred [6,27-30,36-39]. The literature also supports the importance of monitoring body composition, because hidden muscle loss can exist even in patients whose BMI appears normal [30,32-35,42].

Overall, the 85 selected studies collectively reinforce that incorporating early screening, personalised nutritional intervention, and continuous monitoring into standard GI oncology practice is essential for improving treatment success and quality of life [1–5,9-15,18-22,27-42].

Limitations

However, there are limitations to the existing evidence. Many of the studies are observational, with small samples and heterogeneous methods, which limits the ability to establish strong causality [6,14,15,18-21,36-39]. Differences in assessment tools, cut-offs and outcome definitions make direct comparisons difficult [1,2,9-11,16,19,32,34,40,41]. Some trials lack long-term follow-up and focus mainly on surrogate outcomes such as weight change or short-term toxicity rather than survival and patient-reported outcomes [5,7,8,11-13,22,26].

Additionally, most studies were conducted in specialised centres in high-income or upper–middle income countries, reducing generalisability to settings such as India where resources, dietary patterns and health-system constraints differ [6,21,31,33,36-39]. Only a limited number of studies formally evaluated ADR causality with Naranjo or severity with Hartwig–Siegel scales, so the true burden of nutrition-related ADRs might be under-estimated [24,25].

The present review is also dependent on English-language publications and the quality of reporting within individual studies. Despite these limitations, the overall direction and consistency of findings across diverse designs and populations are strong [1–5,9-15,18-22,27-42].

Interpretation

When interpreting the findings of these articles together, it becomes clear that nutritional care is a vital part of cancer treatment, not an optional add-on. Malnutrition is not a late-stage complication but a frequent early-stage condition that can worsen rapidly if not addressed [6,9,14,15,27-30,34,36-40]. Poor nutritional status acts as a modifiable barrier to effective chemotherapy delivery because it increases toxicity risk and reduces tolerance to full treatment doses [3,16,18-22,30,40].

Improved nutritional intake and muscle preservation can therefore indirectly support better tumour control by allowing patients to stay on optimal therapy [3,11-13,18,22,26]. The articles also reveal strong links between systemic inflammation, cachexia and nutritional decline, indicating that nutrition cannot be separated from overall disease biology [21,30,32-35,42].

Evidence from prehabilitation and combined interventions shows that when nutrition support is integrated with exercise and symptom management, treatment readiness improves significantly [4,22,30,42]. The literature also indicates that even relatively small changes in weight or muscle mass have major clinical implications, reinforcing the need for timely detection [9,14,27-30,32-35].

Although oral nutritional supplements are beneficial, several studies highlight that adherence must be supported through counselling, symptom relief and patient education [5,7,8,11-13,22,26]. Findings also show that nutrition must be monitored over time because patients can shift from low to high risk within a few weeks during treatment [6,15,17-19,36-39].

Differences in tumour site, culture, diet, and socioeconomic status suggest the importance of personalised nutrition planning [28,29,31-34,36-39]. Composite indices such as PNI and GNRI might be integrated into routine oncology risk assessment strategies to better identify high-risk patients early [9,10,16,19,21,23,30,40]. Many authors argue that nutrition care pathways should be standardised and implemented across cancer centres to address the gap between guideline recommendations and real-world practice [1,2,22,31-33].

Taken together, the studies support a model of GI cancer care where nutritional screening begins at diagnosis, interventions are delivered proactively, and nutrition remains a continuous focus throughout treatment [1-5,9-15,18-22,27-42].

Key Insights

The most important insight is that malnutrition is extremely prevalent in GI cancers and is strongly linked to chemotherapy tolerance, toxicity and survival.[3,6,9,10,14,15,18-22,27-30,36-40] Nutritional status is therefore a key clinical variable, not a minor background detail. Validated screening tools outperform simple measures like weight and should be incorporated into routine oncology workflows.[1,2,11,32,34,40,41]

Increasing evidence shows that improving nutritional status through counselling and oral supplements can meaningfully enhance functional ability and treatment continuation, reducing severe toxicities and hospital admissions.[4,5,7,8,11-13,18,22,26,37-39] By identifying sarcopenia through body-composition assessment, even patients with normal BMI can be protected through early intervention.[30,32-35,42]

The literature also highlights that nutritional care must be multidisciplinary and patient-centric, ensuring adherence and addressing symptom burden directly.[1,2,22,31-33] Since malnutrition leads to longer hospital stays and greater healthcare costs, nutrition care is both clinically and economically important.[6,20-22,37-39]

Overall, the articles collectively reinforce that nutritional optimisation is a modifiable predictor of success in chemotherapy, making it an essential pillar of comprehensive GI cancer management. Your planned prospective study on the impact of nutritional status on chemotherapy response and ADRs in GI cancers aligns strongly with the best available evidence and addresses a critical gap in early identification and prevention of avoidable treatment harm.[3,9,10,16,18-22,30,40].

1. Edwards P. The Encyclopedia of philosophy. New York: Macmillan. 1996; 1: 526-529.
2. Westerhoff HV, van Dam K. Thermodynamics and control of biological free-energy transduction. Russian edition. Moscow: Mir. 1992.
3. Kajtez N. Philosophy of entropy. Novi Sad: Agora. 2019.
4. Yann AB. The Earth from the Air 365 Days. Thames and Hudson. 2001.
5. Brooks DR, Wiley EO. Evolution as entropy: Toward a unified theory of biology. University of Chicago Press. 1988.
6. Jargin SV. Munchausen syndrome by proxy: A report from Russia. J of Gyne Obste & Mother Health. 2024; 2: 01-06.
7. Jargin S, Robertson S. International conflicts and overpopulation: approaching nightfall. Eliva Press. 2025.
8. Jargin SV. K voprosu o materialisticheskom obosnovanii etiki [On the materialist foundation of ethics]. Molodoi Uchenyi-Young Scientist. 2014; 1: 721-726.
9. Doerr W. Entropie und Pathogenese. In: Entropie und Pathogenese. Interdisziplinares Kolloquium der Heidelberger Akademie der Wissenschaften. V. Becker, H. Schipperges (Hrsg.) Berlin: Springer. 1993; 1-5.
10. Schaefer H. Entropie und Pathogenese. In: Entropie und Pathogenese. Interdisziplinares Kolloquium der Heidelberger Akademie der Wissenschaften. V. Becker, H. Schipperges (Hrsg.) Berlin: Springer. 1993; 6-11.
11. Jargin SV. Misconduct in medical research and practice. New York: Nova Science Publishers. 2020.
12. Jargin S. Moscow reconstruction: some mechanisms. Domus Magazine. 2010; 934: 125-126.
13. Becker V. Dissipative Prozesse und Pathogenese. In: Entropie und Pathogenese. Interdisziplinäres Kolloquium der Heidelberger Akademie der Wissenschaften. V. Becker, H. Schipperges (Hrsg.) Berlin: Springer. 1993; 110-116.
14. Jargin SV Dentistry in Russia: Recent history and perspectives. J Oral Dent Health Res. 2025; 7: 193.
15. Jargin SV. On the minimally invasive approach to the gingival recession. J Indian Soc Periodontol. 2013; 17: 394-396.
16. Mokeem LS, Garcia IM, Melo MA. Degradation and failure phenomena at the dentin bonding interface. Biomedicines. 2023; 11: 1256.
17. Tarasenko SV. Hirurgicheskaia stomatologia (Oral surgery). Moscow: Geotar-media. 2023.
18. Krebs KA. Response from the AAP. J Am Dent Assoc. 2005; 136: 1563-1565.
19. Bastendorf KD, Strafela-Bastendorf N, Lussi A. Mechanical removal of the biofilm: is the curette still the gold standard? Monogr Oral Sci. 2021; 29: 105-118.
20. Worthington HV, Clarkson JE, Bryan G, Beirne PV. Routine scale and polish for periodontal health in adults. Cochrane Database Syst Rev. 2013; 12.
21. Heasman PA, Holliday R, Bryant A, Preshaw PM. Evidence for the occurrence of gingival recession and non-carious cervical lesions as a consequence of traumatic toothbrushing. J Clin Periodontol. 2015; 16: 237-255.
22. Sultan N, Jafri Z, Sawai M, Bhardwaj A. Minimally invasive periodontal therapy. J Oral Biol Craniofac Res. 2020; 10: 161-165.
23. Ryder MI, Armitage GC. Minimally invasive periodontal therapy for general practitioners. Periodontol 2000. 2016; 71: 7-9.
24. Biscop S, Dessein B, Roctus J. Putin is creating the multipolar world he (thought he) wanted. EGMONT Royal Institute for International Relations. Security Policy Brief No. 156. 2022.
25. Daniels RV. A documentary history of communism. University Press of New England. 1984.
26. Jargin SV. Selected Aspects of Healthcare in Russia. Paperback and eBook. Cambridge Scholars Publishing. 2025.
27. Woodhead M. 80% of China's clinical trial data are fraudulent, investigation finds. BMJ. 2016; 355: 5396.
28. Brown K. CEO, China: the rise of Xi Jinping. New York: I.B. Tauris. 2019.
29. Voslensky MS. Nomenklatura: the Soviet ruling class. Garden City, NY: Knopf Doubleday Publishing Group. 1984.
30. Borshchevskaya A. The role of the military in Russian politics and foreign policy over the past 20 years. Orbis. 2020; 64: 434-446.