Chapter 24

Cancer

Aetiology and dietary recommendations

Cancer cachexia

Cancer treatment

Managing nutritional status in cancer

Living with and beyond cancer

Frequently asked questions

Neutropenia and food hygiene

Late effects

Palliative care in cancer

Aetiology and dietary recommendations

The incidence of cancer is increasing and, at present, a third of the UK population will be diagnosed with cancer at some point in their lifetime. The aetiology of cancer is complex, with 5% being caused by genetic factors and the remainder the result of a wide range of environmental factors. Diet can be part of this complex picture. The effects of diet probably start during childhood and then continue into adult life. This may be directly caused by the foods eaten, but also through influence of the food on body weight and growth. Other environmental factors include:

tobacco;

infection;

industrial pollutants, e.g. asbestos;

ionizing radiation;

sunlight.

Estimates of cancer preventability by appropriate diet, nutrition, physical activity, and body fatness have been undertaken by the World Cancer Research Fund for four countries and described as the Population Attributable Fraction (PAF). PAF is the proportional reduction in population disease or mortality that would occur if exposure to a risk factor were reduced to an alternative ideal exposure scenario (e.g. no alcohol use). Detailed statistics are available online: image…… http://www.wcrf.org/int/cancer-facts-figures/preventability-estimates/cancer-preventability-estimates-diet-nutrition.

The World Cancer Research Fund has recommended the following basic principles to a healthy eating diet that may support cancer prevention:

Maintain your weight within the normal body mass index (BMI) range.

Be physically active for at least 150 minutes every week and sit less.

Reduce your intake of high calorie foods and avoid sugary drinks.

Eat at least five portions of fruit/vegetables every day.

Eat a portion of pulses or wholegrain foods with every meal.

Reduce your intake of red meat to no more than 350–500 g (12–18 oz) a week and eat minimal amounts of processed meats.

Limit or avoid alcohol. If consumed, limit your alcohol intake to 2 units a day for men and 1 unit a day for women.

Breastfeed your baby.

Do not use dietary supplements for the prevention of cancer.

They recommend that a typical meal should ideally consist of three-quarters of the plate as wholegrain cereals, pulses, vegetables, and fruit, with the remaining one-quarter containing a source of protein such as fish, chicken, egg, or lean meat (Fig. 24.1).

image

Fig. 24.1Healthy plate guide.

Reproduced from ‘Eat well for life’, with permission from the World Cancer Research Fund. © World Cancer Research 2019. image…… https://www.wcrf-uk.org/sites/default/files/eat-well-for-life-booklet.pdf. More information and recipe ideas are available at: image…… www.wcrf-uk.org.

Cancer cachexia

Cancer cachexia is a multi-factorial syndrome which is defined by an ongoing loss of skeletal muscle mass, with or without loss of fat mass, that cannot be fully reversed by conventional nutritional support. It leads to progressive functional impairment and can influence tolerance to cancer treatment (see image…… Chapter 25 ‘Undernutrition’).

The diagnostic criteria are:

weight loss >5%; or

weight loss >2% in individuals showing depletion according to current bodyweight and height (BMI < 20 kg/m2) or skeletal muscle mass (sarcopenia).

The cachexia syndrome can develop progressively through various stages from pre-cachexia, cachexia, to refractory cachexia. The severity can be classified depending on the degree of depletion of energy stores and body protein in combination with the amount of weight loss.1

It is more common in some tumour types such as lung and gastrointestinal cancer and less common in other types of cancer, for example, breast and prostate cancer. Progression of disease increases the risk of cachexia, and refractory cachexia occurs in advanced cancer.

The metabolic features of cancer cachexia are:

Protein metabolism: systemic inflammation is associated with altered protein turnover, a loss of fat and muscle mass, and an increase in the production of acute phase proteins.

Carbohydrate metabolism: systemic inflammation is frequently associated with insulin resistance and impaired glucose tolerance.

Lipid metabolism: the capacity for lipid oxidation is maintained or even increased in cancer patients, and especially so in the presence of weight loss.2

Nutrition screening should be used to identify malnutrition and cachexia as early as possible to facilitate a full nutritional assessment and implementation of a nutrition care plan. Nutrition screening tools which include symptoms that affect food intake are more sensitive to identifying those with cancer who are at risk of undernutrition.3 A full nutrition assessment should be undertaken by a healthcare professional experienced in nutrition and cancer (see image…… Chapter 4 ‘Nutrition assessment’). The Patient Generated Subjective Global Assessment (PG-SGA) is a useful tool providing a framework for a full assessment. It includes assessment of weight change, symptoms affecting food intake, current food intake, physical function, impact of disease, and a physical examination to assess muscle and fat stores. It has been validated in oncology and been shown to be a prognostic indicator.4

Cancer treatment

The diagnosis of cancer requires a multi-professional discussion and plan for the appropriate treatment. Multi-modality treatment is often planned with treatments running concurrently or consecutively and can include any of the following.

Chemotherapy—the use of drugs, either systemically or orally, given with the intention of killing cancer cells. Their actions affect both normal and cancer cells, producing toxicity in normal tissues and organs such as stomatitis, diarrhoea, and bone marrow depression. May be administered intermittently, allowing the body to recover between administration, or continuously. Often produce symptoms that affect food intake including anorexia, nausea, sore mouth, and taste changes. High dose chemotherapy may be given in haematological cancers with the intention of destroying the cancer contained in the immune system. Such procedures require support in the form of a bone marrow transplant or stem cell rescue to restore the function of the immune system.

Radiotherapy—the use of ionizing radiation given with the intention of killing cancer cells. Radiotherapy is directed at the tumour cells. It kills both normal and cancer cells and is given at doses that allow the normal cells to recover and regenerate. Side effects of the treatment are primarily confined to the area treated, for example, a sore mouth or throat when the head or neck is treated or diarrhoea when organs in the pelvis are treated. It may be used in combination with chemotherapy which sensitizes the tissues.

Surgery—may be used before or after other treatments. Usually involves excision of the tumour with adjacent lymph nodes to which the cancer may have spread. May also be used for palliation, for example, to bypass an intestinal obstruction. The effect on nutritional status will vary depending on the extent of the surgery and whether it impacts on intestinal function.

Hormone treatment—cancers that are dependent on hormones to promote growth may be treated with drugs to alter the availability of hormones in the body. These then block or reduce the growth of tissues that rely on hormones. They may influence nutrition via their effects on promoting weight gain and reducing bone density.

Novel therapies—these include experimental and new treatments that may be used in combination with conventional therapies or on their own. They include drugs such as growth factor inhibitors and immunotherapy.

Aims of cancer treatment

Nutritional management can plan an important role during each of the three aims of cancer treatment:

cure—to obtain a complete response;

control—to extend life and quality of life if cure is not possible;

palliation—to provide comfort where cure and control are not possible, to relieve symptoms and maximize quality of life.

Nutritional status during cancer treatment

Weight loss and poor nutritional status can have a negative impact on the ability to withstand cancer treatment. Changes in nutritional status can occur at any time before or after a diagnosis of cancer so it is important that people are screened and assessed on a regular basis. Nutritional interventions and support should be aimed at providing adequate nutritional intake, to maintain muscle mass in conjunction with physical activity and to improve quality of life. The aim is to prevent further deterioration in nutritional status or improve nutritional parameters, reducing the risk of breaks from treatment related to toxicity and to enable planned cancer treatment to be undertaken.

Nutritional requirements

Altered energy expenditure may occur in some people with cancer; however, this is often balanced by a reduction in physical activity. The provision of any form of nutritional status requires an estimation of energy, protein, fluid, and micronutrient requirements with appropriate monitoring. Nutritional requirements can be estimated by the following:

25–30 kcal/kg body weight

1.0–1.5 g protein/kg body weight.2

When planning artificial nutrition support it is advisable to assess each individual using the Henry equations (see image…… Chapter 25 ‘Estimating requirements in disease states’) with the appropriate estimated stress and activity factors.

The optimal ratio of carbohydrate to fat intake has not yet been established. In patients with insulin resistance, uptake and oxidation of glucose by muscle cells is impaired while the use of fat is normal or increased.2 It may be prudent when planning higher energy diets to promote weight gain to increase the ratio of fat to carbohydrate to meet energy requirements.

Micronutrient requirements are assumed to be similar to those of healthy individuals. It is unclear how high doses of vitamins, particularly antioxidants, influence toxicity of treatment, particularly chemotherapy and radiotherapy and overall survival.5

Managing nutritional status in cancer

The risk of malnutrition in cancer should be identified early to allow interventions to be planned, preventing a further deterioration in nutritional status. Nutritional therapy in cancer patients who are malnourished or at risk of malnutrition has been shown to improve body weight and energy intake but not survival.2

Dietary counselling, by healthcare professionals with the relevant knowledge and experience in cancer, should provide advice and support focused on eating and drinking, whenever this is possible. Although the research evidence does not suggest routine use of artificial nutritional support, it may be required in some circumstances when oral intake is insufficient because of the tumour itself or because of the side effects of planned treatment. If the gastrointestinal tract is functioning and can be accessed, then this should be the route of choice. Timing of the placement of an enteral feeding tube is important to ensure that this is done when the person is able to withstand the procedure and not when they are at increased risk of infection. Parenteral nutrition should be reserved for those with a non-functioning gastrointestinal tract, for example, in bowel obstruction or with a high output fistula (see image…… Chapter 26 ‘Fistulae’).

Managing symptoms

Symptoms affecting food intake are common in people with cancer and increase the risk of weight loss and malnutrition.6 The most frequent symptoms include no appetite, early satiety, taste changes, nausea, dry mouth, constipation, dry mouth, vomiting, and difficulties with swallowing. Medical management is essential for patient comfort and to reduce the impact on the oral intake of food and fluids. Dietary interventions can also help manage symptoms (Table 24.1).

Table 24.1 Dietary interventions to help manage symptoms7

Symptom Dietary advice and suggestions
Weight loss Food fortification—use of higher fat alternatives and addition of energy dense foods to meals and snacks
Changes to meal patterns to promote small frequent meals and snacks
High energy snacks, e.g. nuts, seeds, cheese, chocolate, fruit and nut bars
Use of high energy drinks, e.g. milky drinks including coffee and hot chocolate, milkshakes, smoothies
Use of commercial oral nutritional supplement drinks
Use of commercial energy supplements to add to food, drinks, or to be taken separately
Poor appetite Serving small portions
Meal pattern of little and often throughout the day
Food fortification
Relying on foods that are palatable
Nausea Use of anti-emetics prior to eating
Avoiding the smell of food
Cold foods may be preferable as they have less odour
Choose carbohydrate-based foods such as crackers, toast, plain biscuits, or cookies
Sip glucose-containing drinks
Try drinks and foods that contain ginger, for example, ginger tea or ginger ale
Sore mouth Appropriate mouthcare as advised by medical team
Plenty of fluids and use a straw if lips are sore
Avoid the use of salty, spicy, and sharp foods
Reduce seasoning, especially salt, in food
Foods that are soft, bland, and easy to eat
Cook cereals until they are soft and mash vegetables
Use of high energy drinks, e.g. milky drinks including coffee and hot chocolate, milkshakes, smoothies
Use of commercial oral nutritional supplement drinks avoiding sharp fruit flavours
Taste changes Often taste for tea and coffee is affected, if so, try fruit and herb teas, for example, berry, mint or camomile
If unable to detect flavours then increase seasoning, use herbs, salt, or citrus fruits such as lime and lemon
Try hot or warm foods
If foods such as meat taste metallic, then try different sources of protein including eggs, yogurt, and cheese
Dysphagia Foods that are soft and easy to eat
May require puree foods with advice about food fortification
Use of high energy drinks, e.g. milky drinks including coffee and hot chocolate, milkshakes, smoothies
Use of commercial oral nutritional supplement drinks
Early satiety Consider anti-emetics that promote gastric emptying
Small frequent meals and snacks
Avoid large volumes fluid consumed before or during mealtimes

Living with and beyond cancer

A diagnosis of cancer often leads people to research whether any particular foods or diet may influence the growth of their disease. This subject is highly complex and can be controversial. Dietary recommendations produced by the World Cancer Research Fund, following a systematic review of the available research evidence, are recommended for people who do not have any specific difficulties with eating and drinking. These principles are generally the same as those outlined in earlier in this chapter, ‘Aetiology and dietary recommendations’. However, for some diagnostic groups there may be specific considerations, e.g. indication of links between better survival and consuming foods containing soy in people with breast cancer.8

There is emerging evidence of the benefit of maintaining a body weight in the normal range, eating a healthy balanced diet, and being physically active after diagnosis. The evidence is strongest in colo-rectal, breast, and prostate cancers, with the impact being on either cancer-related mortality or overall health in the prevention of other chronic diseases such as cardiovascular disease and diabetes.9

Frequently asked questions

Sugar People do not need to avoid sugar to prevent or cure cancer. Cancer cells, like all other cells in the body, use glucose for energy. Some people have suggested that reducing sugar intake can minimize cancer cell growth. However, restricting the amount of sugar has not been proven to slow down or control the growth of cancer cells and, therefore, it does not need to be avoided. Reducing sugar in the diet can be a useful way to help someone lose weight.

Vitamin and mineral supplementation If an individual follows the principles of healthy eating, then the diet is likely to provide all the vitamins and minerals required. However, there may be times when eating is more difficult and an individual is unable to eat sufficiently to meet their requirements. In this situation, a one-a-day multivitamin and mineral supplement would be recommended to meet the needs of the individual.

At present, there is no evidence that taking extra vitamins as supplements will reduce the chance of cancer coming back. Very high doses, i.e. well above the reference nutrient intake, may be harmful and have unpleasant side effects or may interact with medication.5

Alternative and complementary diets People with cancer often obtain dietary information from the Internet, media, family, and friends. This may relate to individual foods, vitamins, minerals, supplement, or diets that claim to influence the growth of cancer. Such diets may vary widely in the foods they advise, but there are some common features including high consumption of vegetables, vegetable juices, and low sugar fruits and often avoid sugar or refined carbohydrates, grains, dairy, and meat. Some include a ‘juice fast’ or abstinence from nutrients for a period of time. Some are particularly prescriptive regarding the consumption of carbohydrate, limiting this with the aim of producing ketosis (ketogenic diet). The rationale behind the use of ketogenic diets is that normal tissues are able to use ketones but cancer cells are not and they continue to metabolize glucose.

A review of alternative cancer diets did not identify any clinical evidence to support their use.10 Regimens suggested are often restrictive and put the person at risk of an unbalanced dietary intake and weight loss. Diets for which no clinical benefit has been shown, but which may entail risks should not be recommended. Patients seek such diets as they appear to provide hope and a cure. Advice and support for patients exploring such diets should take the psychological aspects into account.

Neutropenia and food hygiene

Neutropenia occurs when there is a low number of white blood cells called neutrophils. When neutrophils are low the immune system is weakened, making it harder to fight infection. This means a greater risk of food poisoning and illness. Neutropenia can be caused by a blood cancer or blood condition. It can also happen during or after treatment. Some of these treatments include: chemotherapy, a bone marrow or stem cell transplant, and medications that suppress the immune system (such as steroids, cyclosporine, and monoclonal antibodies). To help protect against food-borne organisms, it is important to follow good hygiene practices and avoid particular foods. The following advice should be given to all patients undergoing cancer treatment.

Food preparation

Wash your hands thoroughly with soap and warm water before cooking, after touching the bin, going to the toilet, and before and after touching raw food.

Wash all worktops and chopping boards before and after cooking.

Use different chopping boards for raw and ready-to-eat foods.

Keep raw food away from ready-to-eat foods such as bread, salad, and fruit.

Store raw meat in a clean, sealed container on the bottom shelf of the fridge.

Wash fruit and vegetables under cold running water before eating.

When cooking, check food is piping hot throughout before eating.

Foods to avoid

It is recommended that these foods are avoided because they are associated with an increased risk of listeria, campylobacter, salmonella and toxoplasmosis:

uncooked soft cheeses with white rinds, e.g. Brie, chevre (i.e. goats’ cheese);

uncooked blue cheeses, e.g. Gorgonzola, Roquefort, and Stilton;

pâté—meat, fish, and vegetarian;

raw and undercooked meat;

raw shellfish;

unpasteurized milk;

raw and partially cooked eggs (follow local guidance).

People with prolonged, severe neutropenia such those undergoing a bone marrow transplant or peripheral stem cell transplant may require additional food restrictions. Guidance is published by the charity, Bloodwise: image…… https://bloodwise.org.uk/sites/default/files/documents/Eating_Well_With_Neutropenia_2017_0.pdf

Late effects

There may be later consequences of cancer treatment that impact on dietary intake, nutritional status, and the risk of developing other diseases such as cardiovascular disease and diabetes (Table 24.2).

Table 24.2 Late effects of cancer diagnosis and treatment on nutrition

Cancer diagnosis Late effects Effect on nutrition
Head and neck cancer Dysphagia, xerostomia, taste changes Continued weight loss after treatment
Upper gastrointestinal cancer Early satiety
Stricture following surgery or radiotherapy
Altered bowel habits
Dumping syndrome
Continued weight loss after treatment
Malabsorption
Deficiency of vitamin B12 following gastrectomy and requirement for prophylactic vitamin B12
Anaemia
Gynae-oncology Altered bowel habits following radiotherapy
Risk of bowel obstruction because of disease, adhesions, or radiotherapy changes
Surgery may result in formation of ileostomy or colostomy
Restricted dietary intake
Early satiety, vomiting
Malabsorption of food and fluids, e.g. with high output intestinal stoma
Vitamin and mineral deficiencies
Haemato-oncology Graft versus host disease
Changes in bowel habits caused by radiotherapy
Increased risk of metabolic syndrome
Weight loss
Poor dietary intake
Vitamin and mineral deficiencies
Urology, breast, brain, and central nervous system tumours Increased risk of metabolic syndrome and increased adiposity
Osteoporosis in hormone-related cancers such as prostate and breast
Obesity
Poor vitamin D status
Childhood cancers Recurrence of childhood cancer and risk of new cancer
Altered gastrointestinal function
Poor growth
Nutritional deficiencies

Palliative care in cancer

Palliative care is traditionally for those patients with advanced incurable disease. Nutrition has a role2 and, as with all palliative care, should be considered in a holistic way considering all aspects of care and, importantly, the patient’s wishes. All decisions should be validated and reviewed on an ongoing basis. It is vital that nutritional concerns are identified early. There is limited evidence of benefit from nutritional support in survival or comfort for patients with weight loss secondary to refractory cancer cachexia.11 As with any patient identified with nutritional issues, holistic assessments should be made, establishing what is appropriate for that individual. This may include: food fortification advice, nutritional supplements, texture modification, or artificial nutritional support.

Artificial nutritional support should always be considered with care,12 with the benefits and burdens being explored. Ethically and legally, artificial nutritional support is deemed a medical treatment and can be withdrawn if in the best interests of the individual; however, emotionally, nutrition can be seen as a ‘source of life’ and, as such, a lack of nutrition as causing starvation.13 In particular, home parenteral nutrition (HPN) should only be considered:11

if the patient has a WHO performance status of ≤2;

when enteral nutrition is insufficient;

when the expected survival because of tumour progression is >2-3 months;

when HPN is expected to stabilize or improve performance status and quality of life; and

the patient desires this mode of nutrition support.

See also image…… Chapter 35, ‘Palliative care’.


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2Arends, J., et al. (2017). ESPEN guidelines on nutrition in cancer patients. Clin. Nutr. 36, 11–48.

3Shaw, C., et al. (2015). Comparison of a novel, simple nutrition screening tool for adult oncology inpatients and the Malnutrition Screening Tool (MST) against the Patient-Generated Subjective Global Assessment (PG-SGA). Support Care Cancer 23, 47–54.

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8World Cancer Research Fund. (2014). Diet, nutrition, physical activity and breast cancer survivors. Available at: image…… http://www.wcrf.org/sites/default/files/Breast-Cancer-Survivors-2014-Report.pdf.

9Moug, S.J., et al.(2017). Lifestyle interventions are feasible in patients with colorectal cancer with potential short-term health benefits: a systematic review. Int. J. Colorectal Dis. 32, 765–75.

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11Bozzetti, F., et al. (2009). ESPEN guidelines on parenteral nutrition: non-surgical oncology. Clin. Nutr. 28, 445–54.

12Druml C et al. (2016). ESPEN guideline on ethical aspects of artificial nutrition and hydration. Clin. Nutr. 35, 545–56.

13Department of Health. (2013). More care, less pathway. A review of the Liverpool care pathway. Available at: image…… https://www.gov.uk/government/publications/review-of-liverpool-care-pathway-for-dying-patients.