Malnutrition In Cancer Patients: What it is, and Why It Matters

What is Cancer Associated Malnutrition?

Malnutrition in cancer patients, known as Cancer-Associated Malnutrition or CAM for short, is a serious condition that is characterized by significant weight loss and the lack of sufficient nutrients that are needed for patients to function normally. CAM can result from cancer itself and/or from the cancer treatments aiming to eradicate the tumor. CAM’s progression is controlled by the tumor, so it often makes patients weaker and more susceptible to infection and tumor side effects. This is why preventive measures to address CAM are often an integral part of a holistic strategy to treat cancer.

How is CAM different than malnutrition?

CAM differs from malnutrition in that they have different causes, and also affect the nutritional makeup of patients in different ways. While normal malnutrition develops from a lack of sufficient amounts and types of nutrients to the body, CAM goes beyond this type of starvation. Because CAM can result from the effects of the tumor, such as metabolic alterations or by anticancer treatment side effects, it can be very dangerous and difficult to treat.

A key difference between malnutrition and CAM is how they deplete nutrients in the body. Malnutrition is typically defined as a loss of energy, protein and fat stores that significantly affect body tissue and organ function. Malnourished patients will first lose body fat stores without a significant loss of muscle mass. This does not happen when patients have CAM.

CAM patients will lose muscle mass resulting in protein degradation, as well as several other symptoms that affect both psychological and physical processes (Argiles). Other indications include altered metabolic functions, a sense of satiety before consuming enough nutrients, lowered food intake, damaged immune system, and dangerous lean muscle mass loss (Meyenfeldt). Cachexia is a specific form of CAM that occurs mostly in patients whose disease is in an advanced stage. Overall, CAM is more complex than malnutrition, and cannot be fixed simply by eating.

Factors that Affect Metabolism in CAM

A cancerous tumor not only affects a patient’s metabolism as it competes with the tumor for resources, but it also alters how it digests macronutrients. There is a link between how much energy a patient uses on a daily basis, and weight loss in cancer patients because the tumor and patient compete for nutrients that contributes to starvation. The presence of a tumor also causes the metabolism to break down nutrients differently. For example, muscle atrophy can occur when more proteins are being broken down to create a primary energy source.

Another factor that affects CAM is related to tumor secretions because they induce skeletal muscle breakdown. Lipolysis, or the breakdown of fats, can also occur. These are examples of how the body’s normal functions are altered by cancer during its progression.

How Cancer Treatments Can Lead to Anorexia and Other Food Aversions

Different surgery requiring resections of the oral, esophageal, and gastrointestinal tract, can cause the side effect of decreased food intake (Cutsem & Arends) for the patient.  Reduced taste sensitivity is also very common in surgeries involving the tongue, taste buds, and saliva glands from the alterations in the thickness of the saliva, and the olfactory nerve, which affects the sense of smell (Cutsem & Arends).

Chemotherapy can have many dangerous and perpetuating consequences based on the location and length of treatment. Taste and smell changes and aversions are common; changing appetite and taste cause a decrease in pleasure from food, limiting the number of nutrients a patient consumes.  Chemotherapy consequences increase when treating areas in the gastrointestinal tract. Mucositis, which is the painful inflammation and ulceration of the lining of the digestive tract, can occur anywhere along the digestive tract, causing lesions (Cutsem & Arends). An array of other side effects such as nausea, vomiting, constipation, early satiety, and bloating all affect the digestive system and create physical and mental aversions to food intake.

Similar to chemotherapy, radiotherapy contributes to CAM depends on the location and length of time treating the tumor. The gastrointestinal mucus is very vulnerable to radiation because it has a toxic effect on the microvilli of the GI mucus (Cutsem & Arends). This makes digestion of valuable nutrients more difficult on both a comfort and functionality level. Radiation can harm sensory aspects of eating, such as taste buds on the tongue, by reducing secretion of and altering the thickness of saliva. Overall, the location of the radiation affects the aspects of food intake related to that location.  

CAM is caused by many different factors stemming from a wide variety of areas in cancer and its treatment. It is important to reiterate the cyclical nature of this disease and how dangerous it can be if proper treatment for CAM is not integrated as part of the whole treatment plan for a cancer patient.

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