Anorexia is an abnormal loss of the appetite for food. Anorexia can be caused by cancer, AIDS, a mental disorder (i.e., anorexia nervosa), or other diseases.

Cancer and cancer treatments may affect taste, smell, appetite, and even the ability particularly in oral cancers, to eat enough food or absorb the nutrients from food. This can cause malnutrition, a condition caused by a lack of consuming by mouth or through supplemental feeding systems like PEG tubes, key nutrients. Malnutrition can cause the patient to be weak, tired, and unable to fight infections or even get through cancer treatment. Malnutrition may be made worse if the cancer grows or spreads. Eating too little protein and calories is a very common problem for cancer patients, particularly oral cancer patients as they develop painful mucositis sores in their mouths during treatments that can persist for some period during and after the completion of treatment. The sores make it very painful to take nutrition by mouth. Having enough protein and calories is important for healing, fighting infection, maintaining lean body mass, and having enough energy.

Anorexia and cachexia are common causes of malnutrition in cancer patients. Anorexia may occur early in the disease or later, if the cancer grows or spreads. Some patients already have anorexia when they are diagnosed with cancer. Almost all patients who have advanced cancer will have anorexia. It is the most common cause of malnutrition in cancer patients.

Cachexia is a condition marked by a loss of appetite, subsequent weight loss, lean body mass/muscle loss, and general weakness. It is common in patients with tumors of the lung, pancreas and upper gastrointestinal tract as well as oral cancer patients. One of the side effect of prolonged treatments be they radiation, chemo, or surgery to the oral environment, is that the side effects of this chronic discomfort can be a lack of enthusiasm to eat. Besides the difficulty in swallowing, the oral pain and discomfort, even taste is radically altered and there is no pleasure in eating. Combine this with the fact that patients become increasing lethargic and sleep for protracted periods during radiation treatments for oral cancer, and you have the makings of malnutrition and wasting of lean body mass. It is important to watch for and treat cachexia early in cancer treatment because it is hard to correct. It is worth mentioning that dehydration can also occur during this time, often requiring IV transfusions in a hospital setting to rehydrate patients. It can be caused by a general lack of desire to drink, again from the pain incurred in swallowing, and also from protracted periods of nausea and diarrhea brought on by both radiation and chemotherapy treatments.  For patients on PEG feeding systems, it is important to remember that in addition to the liquid diet supplement used by these systems, that adequate amounts of water are also added to the formula at each feeding.

Cancer patients may have anorexia and cachexia at the same time. Weight loss can be caused by eating fewer calories, and by burning more calories, or both. It requires a great deal of energy for the body to be in a constant state of repair and rebuild from the ongoing treatments and the destruction of not only cancerous tissues but collateral healthy tissue as well. It is important that cancer symptoms and side effects that affect eating and cause weight loss are both anticipated and treated early. Both proper nutrition therapy and medicine can help the patient stay at a healthy weight. Most major cancer centers employ, and have as part of the treatment team, a nutritionist that is capable of monitoring a patient’s nutritional intake and body weight.

Medicine may be needed to offset these side effects by targeting the following:

  • To help increase appetite.
  • To help digest food.
  • To help the muscles of the stomach and intestines contract (to keep food moving along).
  • To prevent or treat nausea and vomiting.
  • To prevent or treat diarrhea.
  • To prevent or treat constipation.
  • To prevent and treat mouth problems (such as dry mouth, infection, acute oral pain, and sores).
  • To prevent and treat general pain in other areas of the body.