Nutritional Assessment of the Cancer Patient

Nutrition is not often thought of as a critical issue in cancer management, but can be an important variable that effects quality of life and survival times. In patients with cancer, particularly metastatic disease, it is not a question of curing the patient, but a question of how can the quality of life for the patient be increased. Over the past 20 years there has been a growing literature base concerning the role of certain macronutrients (fats, protein, and carbohydrate) and micronutrients, (vitamins, minerals, fatty acids and amino acids) on neoplastic diseases. Though this area of investigation is still in its infancy, there is increasing evidence that nutritional management of neoplasia can have profound effects on the lives of the animals and owners that are involved in this disease process.

Joseph J. WAKSHLAG
BS, MS, DVM

Joseph Wakshlag graduated with a BS and MS from Montclair State University, and a DVM from the Cornell College in Veterinary Medicine. He is currently pursuing a PhD in pharmacology and is involved in residency training in Veterinary Nutrition. Research interests include the mechanisms of lean body wasting in dogs and cats, as well as amino acid and fatty acid metabolism in neoplasia. Extracurricular interests include metabolism of the athletic animal, which he directly examines 365 days a year in his kennel of Euro-hound sprint racing sled dogs.

Francis A. KALLFELZ
BS, DVM, PhD, Dipl ACVN

Francis Kallfelz graduated from the Cornell College of Veterinarian Medicine in 1962 and continued on to receive his PhD in physiology in 1966 studying calcium metabolism. Soon after graduating he became a faculty member in the department of Clinical Sciences at the Cornell College of Veterinary Medicine. He served as hospital Director from 1986 - 1997 and was also intimately involved with the Chartering of the American College of Veterinary Nutrition, which was established in 1988. Francis Kallfelz is presently the James Law Professor of Nutrition in the Department of Clinical Sciences. Though much of his career has been spent researching calcium, phosphorus, magnesium and vitamin D metabolism and absorption, his more recent research interests have been examining protein requirements and the molecular mechanisms of lean body wasting.

1. Nutritional Assessment of the Cancer Patient

Though not the focus of this chapter, a patient that presents with anorexia requires immediate attention including administration of enteral, or possibly partial or total parental nutrition (see Chapter 14). It is often difficult to determine whether weight loss is due to anorexia, or cancer cachexia. Often in advanced neoplastic diseases there is an element of intermittent anorexia associated with chemotherapeutic treatment of the disease itself.

Clinically, cachexia can be defined as progressive weight loss in the face of apparent adequate caloric intake. This situation may be caused by a variety of mechanisms, but is most commonly thought of as an alteration in the basal metabolic rate resulting in an increased resting energy requirement. However, other factors which are not due to an increase in the metabolic rate may also result in lean body wasting.

Obtaining a good history, a thorough physical examination, personal assessment and patient follow-up is critical in determining the metabolic status of the animal. To differentiate whether a cancer patient is hypermetabolic or if there are other mechanisms causing lean body wasting requires not only assessment of body weight, but also determining body condition score and attempting to subjectively determine whether there has been abnormal lean body wasting in the patient.

When cancer is diagnosed in a dog, the veterinarian generally encounters one of three situations:

1. Neoplasia without nutritional complications
2. Neoplasia with anorexia
3. Neoplasia with cachexia

A veterinary study suggested that a significant sub-population (27%) of feline cancer patients will develop cachexia (Baez et al., 2002). The percentage of canine cancer patients with cachexia has not yet been determined, but as treatment modalities extend the survival times of canine cancer patients, cachexia may become more prevalent.

Sophisticated tools including Dual Energy X-ray Absorptiometry (DEXA) and bioelectrical impedence can be used to assess lean body mass, however, these modalities are not available to most clinicians. Therefore regular measurement of body weight and body scoring are essential when monitoring neoplasia.

In general, anorexia will result in weight loss primarily of adipose tissue, while patients with cachexia will lose nearly equal amounts of skeletal muscle and fat mass (© JY Deschamps).

When assessing the cancer patient for excessive weight loss and lean body wasting, other diseases that must be ruled out include diabetes mellitus, cardiac disease, renal disease, and hyperthyroidism, since biochemical and hormonal stimulation of weight loss and cachexia may also occur in these diseases as well.

Guidelines that have been reported in studies of human cancer patients help to define abnormal weight loss and aid the definition of the cachectic response (Inui, 2002) (Table 1 & Table 2).

Close scrutiny of scapular, hindlimb, and masticatory musculature is routinely necessary is cachexia is suspected (Baez et al., 2002). Bony prominences such as the glenoid tuberosity, the spine of the scapula, the tuber ischii, greater trochanter of the femur and the sagittal crest of the skull become more evident in a short period of time.

Examination of the gluteal musculature and paralumbar muscles which lead to prominence of the ileal crest and vertebral spines are also easily useful for assessing lean body wasting (Figure 1). Similar to body condition scoring (BCS) for obesity, there is a muscle condition scoring (MCS) system in development. This tool should be available for clinicians in the near future to help define cachexia and abnormal lean body wasting in dogs.

Figure 1. Emaciated appearance due to inappropriate lean body wasting. Note the prominent ribs, hips, vertebrae and sagittal crest as well as the loss of hindlimb and pectoral musculature (© Courtesy of the Cornell Comparative Oncology Program).