clinical practice
Nutrition therapy
Monitoring the nutritional
status of cancer patients helps
boost treatment outcomes.
By Kellie Bilinski
M
alnutrition 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
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 or freecall 1800 812 942.
References at www.nursingreview.com.au
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