Nutritional support for the treatment of cancer patients and between treatments

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In the past half century, malignant tumors have become a common life-threatening disease in China, malnutrition and nutritional risks are huge challenges faced by tumor patients, and even become one of the important causes of
death for tumor patients.
The data show that 40%~80% of tumor patients have different degrees of malnutrition, and about 20% of tumor patients die due to malnutrition and its complications, rather than the tumor itself¹.

As cancers that are more prone to malnutrition, gastric cancer, esophageal cancer, lung cancer, liver cancer and colorectal cancer are in the forefront of tumor mortality
.

For tumor patients, in addition to the increase in nutritional requirements brought about by tumor metabolism itself, treatment and treatment-related side effects, such as nausea and vomiting caused by chemotherapy, decreased appetite, dysphagia and diarrhea caused by mucositis caused by radiotherapy, will further aggravate the malnutrition of tumor patients, therefore, it is of great significance for tumor patients to give patients better nutritional support treatment in the treatment and treatment interval in clinical work
.

The need for nutritional support

Nutritional support for cancer patients can prevent further deterioration of the body's nutritional status and ensure that the patient's body can tolerate treatment measures such as surgery, radiotherapy or chemotherapy, so as to obtain better long-term treatment results
.
Studies have shown that for patients with malnutrition before surgery, nutritional support for 7~14 days before major surgery is beneficial to reduce postoperative complications, promote wound healing, and shorten hospital stay¹.

Even if the patient's tumor has affected multiple organs and the body's consumption is serious, nutritional support can also play a role
in slowing down its own consumption.
A large number of studies have found that reasonable and effective provision of nutritional support does not increase tumor recurrence or metastasis rate and reduce survival rate, but can significantly improve the postoperative nutrition and immune status of tumor patients, reduce the occurrence of postoperative complications and infections, improve the treatment rate of patients, reduce the mortality rate, reduce the proportion of drugs and medical expenditure, and have positive significance
for most patients with malnourished tumors.

Therefore, the "Guidelines for Nutritional Support for Cancer Patients" issued by the Chinese Medical Association strongly recommends, "Once diagnosed with cancer, nutritional risk screening and nutritional assessment, including dietary survey, weight loss, physical examination, anthropometric measurement and laboratory examination
.
" Nutritional risk screening and nutritional assessment should be performed multiple times during the treatment of tumor patients"²
.
The European Society for Clinical Nutrition and Metabolism (ESPEN) guidelines for clinical nutrition for cancer also state that "nutritional disorders in oncology patients should be detected as early as possible, and it is recommended that patients be regularly assessed for nutritional intake, weight changes, and body mass index (BMI), and repeat the assessment according to the patient's clinical condition"³.

Principles of nutritional support for oncology patients

The 2021 edition of the Chinese Society of Clinical Oncology (CSCO) Guidelines for Nutrition Therapy for Malignant Tumors⁴ points out that the primary form of nutrition therapy is nutrition education and dietary guidance, and follows a three-step nutrition therapy strategy, namely:

1.
Nutritional risk screening and assessment, nutrition education and dietary guidance should run through the whole process of diagnosis and treatment of malignant tumors;

2.
When the patient has insufficient oral intake, supplementary enteral nutrition is recommended, oral nutrition supplement is preferred, and tube feeding can be considered when the digestive tract function is basically normal, and the intake is insufficient due to eating disorders and other reasons;

3.
When the nutrient requirements cannot be met through oral intake and enteral nutrition, enteral nutrition combined with parenteral nutrition is recommended; When enteral nutrition is not feasible or tolerated, give full parenteral nutrition
.

Recommendations for energy and nutrient intake in patients with tumors

In terms of the daily nutritional needs and specific nutrient intake of tumor patients, the Chinese Medical Association recommends that the daily energy intake should be 25~30 kcal/kg/d, of which protein intake should be guaranteed to be 1.
0~2.
0 g/kg/d, improve the proportion of fat energy supply of patients, increase dietary density, and supplement vitamins and trace elements²
.

CSCO pointed out⁴ that the energy requirement of bedridden patients was 20~25 kcal/kg/d, and that of active patients was 25~30 kcal/kg/d; The daily intake of water should be 30-40 ml/kg/d, the energy supply ratio of carbohydrates and fat refers to healthy people, respectively, 50%~65% and 20%~30%, protein intake should not be less than 1.
0 g/kg/d, and it is recommended to reach 1.
5~2.
0 g/kg/d
.

The effect of antitumor therapy on the body's nutritional metabolism

The nutritional metabolism of tumor patients is different from that of ordinary people, but the specific changes in energy metabolism are still controversial
.
Overall, nearly half of the newly diagnosed tumor patients are in a state of hypermetabolism, and the body's resting energy expenditure increases, which is prone to malnutrition or cancerous cachexia⁻⁶
。 In the process of tumor treatment, the body's nutritional status will be affected by more complex factors, for example, surgical treatment will lead to increased nutritional requirements, while long-term fasting before surgery and reduced postoperative dietary intake will easily lead to a decrease in nutritional status; The radiation field in tumor radiotherapy inevitably involves some normal tissues such as the mouth, pharynx, esophagus, and stomach, which in turn affects the patient's chewing, swallowing, and digestion and other eating processes.
The cytotoxic effects of chemotherapy are the basis of its anti-tumor effects, but it also interferes with
normal cells.
Coupled with the interference caused by treatment-related adverse events, the probability of malnutrition in cancer patients during treatment is greatly increased
.

Dietary countermeasures for different patients during antitumor therapy

The White Paper on Dietary Nutrition of Cancer Patients in China points out that doctors should assist patients to fully understand the existing nutritional problems, help patients formulate reasonable diet plans, and give different suggestions
for patients with different situations.

For example, for anorexic, food should be diversified, small and frequent meals, and meals should be added between meals to create a comfortable and quiet dining environment; For nausea and vomiting, should eat less and more meals, try not to drink water before meals, chew slowly and swallow, do not lie flat for 1 hour after meals, but walk moderately after meals to prevent food reflux; For patients with stomatitis, it is recommended to eat less residue or cold liquid, avoid the intake of irritating foods, keep the mouth clean, and prevent secondary infection; For people with dysphagia, soft food or semi-liquid food, liquid food should be tried, and if coughing and other discomfort occur when eating, you should be vigilant for aspiration pneumonia; For diarrhea, choose less residue and low-fiber food, avoid greasy food, and actively correct water and electrolyte imbalances
.

brief summary

Nutritional support plays a crucial role in multidisciplinary cancer treatment, but cancer-related malnutrition remains largely underappreciated in clinical practice
.
Nutrition therapy is of great significance to cancer patients, hospitals and clinicians should have the concept of full-cycle health management for tumor patients, and improve the clinical path based on evidence-based medical evidence, establish a nutritional risk screening-malnutrition diagnosis-nutritional support treatment-convalescent nutrition management and efficacy monitoring of patients nutrition support treatment chain, so that nutrition therapy truly becomes the most basic and necessary basic treatment measures
for tumor patients.

References

1.
Cancer Nutrition Management Branch of Chinese Nutrition Society.
White Paper on Nutritional Diet for Cancer Patients in China.

2.
Guidelines for nutritional support for tumor patients[J].
Chinese Journal of Surgery, 2017, 55(11):29.

3.
Muscaritoli M, Arends J, Bachmann P, et al.
ESPEN practical guideline: Clinical Nutrition in cancer.
Clin Nutr.
2021; 40(5):2898-2913.

4.
Guidelines for nutritional therapy for malignant tumors of the Chinese Society of Clinical Oncology (2021 edition).

5.
 Bosaeus I, Daneryd P, Svanberg E, et al.
Dietary intake and resting energy expenditure in relation to weight loss in unselected cancer patients[J].
Int J Cancer, 2001,93(3) :380-383.

6.
 Cao DX, Wu GH, Zhang B, et al.
Resting energy expenditure and body composition in patients with newly detected cancer[ J].
Clin Nutr, 2010,29(1) :72-77.