In their article in this issue, Drs. Jatoi
and Loprinzi review much of the data on weight loss and anorexia in cancer
patients from the standpoint of the impact of nutrition and various
pharmacologic agents on management, and they make some sound recommendations for
therapy. The benefit of nutritional interventions in this area are often
overhwhelmed by the patient’s complex disease course and, therefore, are
difficult to demonstrate.
It is now clear that malnutrition occurs for many different
reasons, but that the metabolic abnormalities associated with cancer are largely
due to the host’s response to the tumor. In a sense, these abnormalities are
an unavoidable component of the immune response, but many patients with cancer
lose weight at the same rate as other malnourished patients with chronic
Some cancer patients, especially breast and prostate cancer
patients, are not malnourished but obese. Therefore, it may be helpful to
classify the nutritional approach to cancer patients based on a more global
understanding of the role of nutrition in cancer prevention and treatment
rather than simply looking at weight loss therapy in isolation.
It has been estimated that in adults over age 50 years, one of
two men and one of three women will be diagnosed with some form of cancer during
their lifetime. Many of these people will be successfully treated cancer
survivors who will be interested in preventing a recurrence of their disease.
Weight loss in an obese cancer patient may be desirable. For example, a
reduction in body fat can lead to a reduction in circulating estradiol levels in
postmenopausal breast cancer patients. Moreover, the institution of a healthy
diet rich in fruits and vegetables may, in turn, lead to significant weight
Normal Starvation vs Cachexia
In true cancer cachexia as opposed to normal starvation, weight
is lost disproportionately from protein stores. Calorie restriction of normal
volunteers leads to a 0.25-lb loss of lean mass per pound of weight lost.
Disproportionately greater losses from muscle, due to the effects of cytokines
in patients with an active cancer that interferes with normal adaptation to
starvation, can lead to impaired immune function. However, in most studies the
adaptive loss of muscle mass associated with simple starvation has not been
adequately separated from the disproportionate and rapid loss of muscle mass
that increases the risk of infection. In many malnourished cancer patients,
there is no evidence of malnutrition beyond that which results from the adaptive
response to reduced food intake, and rapidly progressive general weight loss is
much less common than the disproportionate weight loss associated with cancer.
The End-Stage Patient
Twenty years ago, I routinely administered total parenteral
nutrition to end-stage cancer patients. While this produced some salutary
effects in selected patients, the risk-benefit considerations articulated in a
number of reviews and meta-analyses have convincingly argued against routine use
of total parenteral nutrition in end-stage patients.
The Weak Patient Undergoing Therapy
Anorexia and weakness routinely develop in many patients
undergoing chemotherapy or radiation. Such patients should be encouraged to rest
adequately and avoid skipping meals. Nutritional supplements in liquid form are
particularly useful in this population.
As the result of depression, many cancer patients fail to eat at
all and suffer undue amounts of fatigue. On the other hand, some patients equate
weight loss with poor outcome and fight to gain weight during therapy to prove
that they are prevailing over their cancer by eating high-fat desserts and red
meats. Some patients even become obese in the process, and this should not be
encouraged. The period of therapy is usually brief when viewed in the context of
the patient’s overall life span, and if the likelihood of response is high,
then nutrition during therapy should take a backseat to quality-of-life issues.
The Patient Who Wants Nutritional ‘Therapy’
Many cancer patients obtain information on nutrition from books,
friends, health food stores, and the Internet. It is important to advise these
patients that nutrition is not a therapy for cancer, but rather it is a body of
information in the scientific literature that suggests that healthy nutrition
including fruits, vegetables, cereals and grains, reduced dietary fat, and the
achievement and maintenance of a healthy body weight may be beneficial in cancer
prevention. Although the benefit of nutritional advice in reducing cancer
recurrence is far from certain, it can reduce the risk of other chronic
diseases. Some patients also enjoy an improvement in their quality of life from
making nutritional and lifestyle changes.
As Drs. Jatoi and Loprinzi discuss, patients presenting with
weight loss and anorexia should receive nutritional counseling and pharmacologic
therapy as necessary. With increased attention to the nutrition of cancer
patients at all stages of treatment, medical oncologists can provide benefits by
(1) enhancing the physician-patient relationship, (2) obviating needless
alternative therapies, (3) improving quality of life, and (4) preventing the
development of malnutrition through early intervention. Future research on
gene-nutrient interactions in cancer prevention and treatment will point the way
to new approaches.
1. Heber D, Blackburn GL, Go VLW (eds): Nutritional Oncology.
San Diego, Academic Press, 2000.
2. Camoriano JK, Loprinzi CL, Ingle JN, et al: Weight change in
women with adjuvant therapy or observed following mastectomy for node-positive
breast cancer. J Clin Oncol 8:1327-1334, 1990.
3. Owen OE: Obesity in Kinney JM, Jeejeebhoy KN, Hill GL, et al
(eds): Nutritrion and Metabolism in Patient Care. Philadelphia, W. B. Saunders ,