Malnutrition in cancer patients is often associated with loss of lean body mass and can be caused by a combination of factors such as inadequate food intake, decreased physical activity and metabolic derangements, often referred to as cancer cachexia. These derangements can be host- or tumour-derived, such as elevated resting metabolic rate, insulin resistance, lipolysis and proteolysis, which aggravate weight loss and are worsened by systemic inflammation and catabolic factors.1
Reduced food intake is common in cancer patients and a result of primary anorexia (loss of appetite). This can be compounded by secondary factors such as oral ulceration, xerostomia, poor dentition, intestinal obstruction, malabsorption, constipation, diarrhoea, vomiting, reduced intestinal motility, chemosensory alteration and uncontrolled pain. Total inability to eat requires immediate intervention, such as total parenteral nutrition, unless otherwise indicated, to avoid starvation.2
Numerous recommendations suggest cancer patients should be screened for risk or presence of malnutrition, due to its negative effect on treatment outcome. Both a low body mass index and weight loss have been shown to independently predict survival.3
Loss of muscle mass is the main aspect of cancer-associated malnutrition that predicts risk of physical impairment, post-operative complications, chemotherapy toxicity and mortality.4 Nutritional and metabolic therapy, therefore, must emphasise the maintenance or gain of muscle mass.
The collective derangements of dietary intake and metabolism described can be optimised by nutrition therapy when used in conjunction with medical management of pain and symptoms, pharmacological agents and physical activity. Nutrient requirements should be met (unless contraindicated) in cancer patients by offering the appropriate nutritional interventions, which may range from counselling alone to parenteral nutrition. Professional nutrition counselling from an accredited practising dietitian (APD) is first-line therapy for cancer patients. This entails detailed and repeated communication aimed at ensuring patients have a thorough understanding of nutrition that will lead to a change in eating habits.
Clearly, the best way to maintain or increase energy and protein intake is with normal food. However, as this is not always possible, oral nutrition supplements may be useful. Oral nutrition supplements are mostly nutritionally complete and can be consumed in addition to food. However, if this is insufficient, supplemental or complete oral, enteral or parenteral nutrition may be indicated, depending on the level of function of the gastrointestinal tract.5
Although there are clear benefits to nutrition therapy, these benefits must be weighed against the risks, burden and cost. This is particularly apparent in advanced cancer where the expected benefits of nutrition therapy may be outweighed by, for example, being attached to a feeding device or gastrostomy placement, in the days preceding death.
There is little data on the optimal time to start nutrition therapy. Patients who are likely to develop anorexia or gastrointestinal issues during treatment should be offered nutrition support before they become severely malnourished, whereas those who are already malnourished should be offered nutritional support immediately.
Nutritional therapy in cancer patients who are malnourished or at risk of malnutrition has been shown to improve body weight, energy intake and quality of life but not survival. A recent systematic review showed that nutrition therapy improved quality of life in cancer patients who were malnourished or at risk of malnutrition.6
The overall goal of nutrition therapy is to provide patients with a nutritionally adequate diet which includes all essential macro- and micronutrients. As in all forms of malnutrition, there is a high risk of micronutrient deficiency, particularly the water-soluble vitamins. In view of this, the use of multivitamin/mineral supplements in doses that approximate nutrient requirements is safe and useful.7
Vitamin D deficiency has been commonly reported in cancer patients and has been associated with poor prognosis and survival in numerous studies.8,9 However, it is not known whether repleting vitamin D stores in cancer patients will improve prognosis. In general, high doses of any vitamin or mineral supplement is not recommended.10 A recent meta-analysis of 68 randomised prevention trials including more than 230,000 participants was unable to show any protective effects of antioxidants but did find a slightly raised mortality in subjects consuming beta-carotene, vitamin A or vitamin E.11
In another study of over 290,000 men, multivitamin supplements were associated with a significant increase in mortality from prostate cancer.12 In patients with early colon cancer, multivitamin supplements were not associated with improved rates of cancer recurrence or overall survival.13 Similarly, 5–8 years of dietary supplementation with beta-carotene (25mg) or tocopherol (50mg) in smokers slightly increased the risk of lung cancer.14 Another trial failed to show that long-term supplementation with vitamin E (400 IU/day) nor selenium (200 mg) had a beneficial effect on incidence of prostate cancer.15 A prospective observational trial in 4459 men with early prostate cancer reported mortality to be significantly increased by a factor of 2.6 in men supplementing selenium in doses of more than 140 mg/day.16 In another randomised control trial (RCT) involving 14,641 physicians in the United States of America, supplementation with vitamin E (400 IU/ day) and vitamin C (500 mg/day) for 10 years was unable to show any benefit on cancer incidence.17
In summary, it is important that patients at risk of malnutrition be identified early and the appropriate intervention commenced. For those who are malnourished, oral nutrition supplements are recommended. Ideally, patients should achieve their nutrient requirements from food, although a multivitamin and mineral supplement is recommended if food intake is inadequate.
For dietary advice for your patients that takes into account their current medical condition, seek support from an APD.
Dr Kellie Bilinski is a post-doctoral research fellow at NICM and Western Sydney University, and a spokesperson for the Dietitians Association of Australia.
To find your local APD, search ‘Find an Accredited Practising Dietitian’ at www.daa.asn.au or freecall 1800 812 942.
References:
- Dechaphunkul T, Martin L, Alberda C, et al. Crit Rev Oncol Hematol 2013;88:459e76.
- Arends J, Bachmann P, Baracos V et al. ESPEN guidelines on nutrition in cancer patients. Clinical Nutrition 36 (2017) 11e48
- Martin L, Senesse P, Gioulbasanis I, et al. Diagnostic criteria for the classification of cancer-associated weight loss. J Clin Oncol 2015;33:90e9.
- Martin L, Birdsell L, Macdonald N, et al. Cancer cachexia in the age of obesity: skeletal muscle depletion is a powerful prognostic factor, independent of body mass index. J Clin Oncol 2013;31: 1539e47.
- Arends J, Bachmann P, Baracos V et al. ESPEN guidelines on nutrition in cancer patients. Clinical Nutrition 36 (2017) 11e48
- Baldwin C, Spiro A, Ahern R, Emery PW. Oral nutrition therapy in malnourished patients with cancer: a systematic review and meta-analysis. J Natl Cancer Inst 2012;104:371e85.
- Norman HA, Butrum RR, Feldman E, et al. The role of dietary supplements during cancer therapy. J Nutr 2003;133(Suppl. 11):S3794e9.
- Rose AA, Elser C, Ennis M, Goodwin PJ. Blood levels of vitamin D and early stage breast cancer prognosis: a systematic review and meta-analysis. Breast Cancer Res Treat 2013;141:331e9.
- Autier P, Boniol M, Pizot C, Mullie P. Vitamin D status and ill health: a systematic review. Lancet Diabetes Endocrinol 2014;2:76e89.
- Rock CL, Doyle C, Demark-Wahnefried W, et al. Nutrition and physical activity guidelines for cancer survivors. CA Cancer J Clin 2012;62:243e74.
- Bjelakovic G, Nikolova D, Gluud LL et al.. Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis. JAMA 2007;297:842e57.
- Lawson KA, Wright ME, Subar A, et al. Multivitamin use and risk of prostate cancer in the national institutes of health-AARP diet and health study. J Natl Cancer Inst 2007;99:754e64.
- Ng K, Meyerhardt JA, Chan JA, et al. Multivitamin use is not associated with cancer recurrence or survival in patients with stage III colon cancer: findings from CALGB 89803. J Clin Oncol 2010;28:4354e63.
- The Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study Group. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med 1994;330:1029e35.
- Klein EA, Thompson Jr IM, Tangen CM, et al. Vitamin E and the risk of prostate cancer: the selenium and vitamin E cancer prevention trial (SELECT). JAMA 2011;306:1549e56.
- Kenfield SA, Van Blarigan EL, DuPre N, Stampfer MJ, Giovannucci E, Chan JM. Selenium supplementation and prostate cancer mortality. J Natl Cancer Inst 2014;107:360.
- Wang L, Sesso HD, Glynn RJ, et al. Vitamin E and C supplementation and risk of cancer in men: posttrial follow-up in the Physicians' Health Study II randomized trial. Am J Clin Nutr 2014;100: 915e23.
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