Wasting (Cachexia)
Cancer frequently leads to widely recognized but poorly understood syndrome known as cachexia. The manifestations of this syndrome are weakness, loss of weight and appetite (anorexia). The patient appears ill and emaciated. The cause of anorexia remains complex and unclear. Muscle biopsies from breast and colon cancer patients show fat content of the muscles to be half of non-cancer patients. There is also an increased break down of proteins in the muscles.
There has been an increasing awareness of cachexia in patients with cancer. In one autopsy series, more than 22 per cent of the patients died without identifiable cause other than cancer cachexia. These patients did not die of their cancer, but of the systemic effects of their cancer that produced the debilitating syndrome that is cachexia. In addition to contributing to mortality, the malnutrition and wasting present serious symptomatic problems.
Cause of Wasting (Cachexia): The cause is not well understood, but there are some contributing factors.
· Cancers at specific sites like esophagus produce mechanical obstruction to passage of food.
· It has been postulated that metabolic demands are increased in cancer patients due to competition by cancer cells for nutrition. Various studies have demonstrated increased nutrients consumption in large sarcomas.
· Other mechanisms like abnormalities of smell and taste, deranged nervous system control and presence of cancer cell secretions in the blood, are all implicated.
· Besides the cancer, treatment can also influence nutritional status of the patient. Chemotherapy and radiation therapy can lead to malnutrition by causing mucositis, enteritis and vomiting, while the stress of surgery produces a hyper-catabolic state. Nutritional consequences of cancer chemotherapy are secondary to its side-effects such as nausea, vomiting, oral pain, diarrhea and fever.
Management: Adequate nutritional support is necessary. When voluntary oral intake is unsatisfactory and the gastro-intestinal tract is functional, feeding via gastric tube is indicated.
When gastrointestinal tract cannot be used for nutritional support, total intravenous nutrition is essential, until tube or oral feeding can be resorted to.
It is likely that by offering such nutritional support before, during and after the treatment, clinical response may improve and also tolerance to therapy.
Total intravenous nutrition is a newer and effective method of nutritional support through which carbohydrates and fats for calories and amino acids for nitrogen requirements, are given. It is useful before the treatment as well as after the treatment with radiation and chemotherapy. However, this involves close monitoring of metabolic needs and careful adjustment of mineral and trace metals in the body.