NUTRITION

Pathophysiology — About 20% of cancer patients die because of gross wasting (cachexia) and no other obvious cause. The dietary intake of protein and calories is insufficient to meet the needs of the tumor, and the patient may experience profound weight loss despite a reasonable food intake. A tumor approximating 2% of body weight can use over 40% of a person’s daily caloric intake. The capacity for a tumor to enlarge while the rest of the body wastes has led some researchers to call a tumor a “nitrogen trap”.

Cancer patients have altered food metabolism, possibly due to tumor hormones such as a cachectin. In starvation the body normally responds by lowering its metabolic rate, but in cancer there is frequently an increased metabolic rate. The pattern of metabolism is changed. A tumor can metabolize large quantities of glucose by the inefficient process of anaerobic glycolysis, which produces lactic acid. The conversion of lactic acid back to glucose in the liver (the Cori cycle) demands energy, as does the breakdown of protein to glucose. These high-energy metabolic processes may account for the raised metabolic rate seen in many cancer patients. Protein metabolism is also affected, and protein breakdown (which slows down after a period of “normal” starvation) continues at a rapid rate in some cancer patients.

I. In patients undergoing vigorous treatment aimed at cure IV hyperalimentation (total parenteral nutrition) is sometimes used in the maintenance of health of patients. It has no advantages over enteral therapy in patients with functioning bowels. Chemotherapy can cause recurrent enteritis. Vigorous nutritional support may help sustain a patient through radical treatment (although firm evidence of this is lacking).

II. Patients with dysphagia enjoying good general well-being, but who are unable to swallow due to cancers of the head and neck, esophagus or stomach, or to neurological conditions such as amyotrophic lateral sclerosis (ALS), can benefit from nutritional support which enables them to ingest enough calories to remain active (and prevents the postural hypotension that under-nutrition can cause).

Management options for this group of patients include:

• Fine bore nasogastric tube

• Gastrostomy

• Jejunostomy

• Pharyngostomy

These procedures may be indicated only in a patient who cannot swallow and who complains of thirst or hunger.

Modern fine bore nasogastric tubes are tolerated quite well. Gastrostomy can be performed percutaneously under endoscopic control. Liquid feeding can be given overnight and disconnected during the day.

IV nutrition is not indicated because it defeats the main aim, which is improved patient activity.

III. Terminally ill patients who are no longer active do not need such invasive nutritional support for several important reasons:

• Intensive feeding does not prolong survival or increase tumor response.

• Intensive feeding cannot reverse weakness or weight loss.

• Intensive feeding does not reduce symptoms or make the patient feel physically stronger.

• Intensive feeding involves medical and nursing procedures (such as tube insertion) which may be unpleasant for a weak patient (and which can create additional problems of leakage and smell).

• Tubes and IV lines tend to increase the emotional distance between patient and family, at a time when emotional closeness is of paramount importance.

For patients who are not active, the more intensive measures are not indicated, but nutritional support continues to be important. Interest in the patient’s food intake carries a message from the caregiver. Advice from a dietitian can be invaluable. (see Diet)

Management options at this stage include:

• Improving appetite (see Anorexia)

• Dietary supplements

• Liquidized food

• Fortifying sip feeds

Dietary supplements containing tasteless glucose polymers can be added to drinks, soups, casseroles or puddings to boost calorie intake.

Sip feedings with nutritionally complete liquid foods can replace eating if the patient is weak. Small frequent amounts (50ml per hour) are encouraged.

«  Humans can survive for many months on a semi-starvation diet.

Comment — A reduced diet does not shorten prognosis in advanced disease. For an inactive patient with advanced cancer a low food intake does not cause hunger. Patients may even occasionally notice that a reduced food intake produces a feeling of well-being (as can a prolonged voluntary fast in a healthy person).

Patients’ concerns ("I’m losing weight" "I’m not eating enough") often relate to worries about having a serious disease and facing death, and need to be understood in the context of spiritual anguish. Patients can usually be helped to come to terms with their true situation by gently explaining their true needs, and allowing them to express their fears. (see Spiritual Pain)

Family members need support, because feeding the patient may have been all they could do to help. Since food is essential for life, family members often wrongly assume that more food will prolong life, and need explanation and reassurance. Family members need help to understand the continuing importance of their supportive role even when they can no longer focus on feeding. (Family members should be discouraged from forcing unwanted food on weak patients.)

Professional carers can be tempted to focus on technical methods of nutritional support, rather than on the more difficult issues of spiritual distress. (“I’m wasting away.”)

The main problems of reduced food intake are the related psychological concerns of the patient, family members and professional carers.

Measures of nutritional support (such as enteral tubes and IV hyperalimentation) which may be appropriate (ordinary) in patients undergoing treatment aimed at cure or enjoying good general well-being, become inappropriate (extraordinary) in far advanced disease, and should usually be avoided. Such measures do not add to the dying patient’s comfort, and may indeed cause unnecessary distress. They may prolong the process of dying by a few days, but do not improve the quality of remaining life.

The decision to remove a tube or IV line is simply one of patient comfort. If the patient wants a tube or IV line removed, it should be removed. If the dying patient is unconscious, professional carers should focus on the real issue, the comfort of the patient, and gently explain to family members that tubes and IV lines do not significantly prolong life.

Removing tubes and IV lines can be difficult if patient, family members or professional carers believe incorrectly that these prolong life, or are needed for comfort. (In Britain, the great majority of patients die with no tubes or IV lines in place, and they die comfortably.)

Teaching professional carers about spiritual support of terminally ill patients and their families gives them skills to help again, and reduces their need to perform technical interventions which have no advantage for the patient and distract attention from more important spiritual and emotional issues.

The author and publisher have taken precautions to ensure that the information in this book is error-free. However, readers must be guided by their own personal and professional standards of good practice in evaluating and applying recommendations made herein. The contents of this book represent the views and experience of the author, and not necessarily those of the publisher.