The diagnosis of a malignancy involves the cancer patient making some changes to certain lifestyle habits. Some of the most noteworthy are those affecting food. Opting for certain foods instead of other foods can help improve the patient’s symptoms, and on many other occasions reduce the malnutrition that is a consequence of the disease. With the aim of clarifying all the doubts cancer patients may have about their eating habits, we spoke to Pedro J. Robledo, nutritionist with the Clinical Nutrition and Dietetics Unit at MD Anderson Cancer Center Madrid.
What is the prevalence of malnutrition among cancer patients?
At diagnosis, prevalence is between 20% and 40%, whilst in the advanced stages of the disease it can reach up to 70% or 80%.
Does the risk and incidence rate of malnutrition vary depending on the origin of the tumor?
Studies show very different statistics for the diagnosis of the incidence rate of malnutrition depending on the organ and area affected by the tumor. For instance, the lowest incidence rates are for skin and breast tumors, and for some early-stage, non-metastatic lymphomas. On the other hand, the highest incidence rates of malnutrition are found in gastric, pancreatic or colon tumors, between 83% and 85%. Other tumors with high incidence rates of malnutrition are those of the lungs and ovaries, with lower rates, around 40% at diagnosis.
Does a malnourished cancer patient have a greater risk of complications?
As we said before, the type of tumor and the stage determine the degree of malnutrition in part, but other factors are involved too and may be metabolic and/or mechanical in type. Other factors like the age of the patient or prior diseases also affect response to treatment.
Does malnutrition affect nutrients?
Malnutrition caused by the tumor may produce mechanical and biological changes, which in the latter case generate metabolic imbalances, by excess or by defect. For example, carbohydrate metabolism is altered by an increase in gluconeogenesis and an increase in lactate/lipids; there is also an increase in lipolysis and protein oxidation. These processes generate a marked loss of body mass and bone and muscle loss. In such a situation, nutritional support is needed.
What does nutritional support for a cancer patient consist of? What strategy should be followed in this case?
Nutritional support aims to prevent premature death brought about by malnutrition and the reduced immunity this causes, providing a better quality of life. A second aim would be to improve tolerance and response to treatment and reduce the complications of treatment. To be able to achieve all this, it is necessary to know the patient’s nutritional state at diagnosis. Above all, the strategy must focus on preventing malnutrition as early as possible. For that reason, assessing the patient from a nutritional point of view prior to treatment is important.
What complications of cancer or its treatment should be treated with modifications to diet?
Modification to diet takes place in relation to the location and type of tumor. In the latter case it would be mainly digestive, esophageal, head and neck tumors. So, diet will be modified in three main cases: in situations related with the general effect of the tumors (dysphagia, ageusia (loss of taste), pseudo-occlusion); in those related with the effects of treatment (diarrhea, mucostitis, nausea and vomiting); and in those requiring therapy for increased toxicity – mainly due to chemotherapy – or for the elimination of components of dietary fiber, gastric acid secretion stimulators, absorption inhibitors or cellular growth stimulants.
What is the difference between parenteral and enteral nutrition?
The biggest difference is the way nutrition is administered. Whilst enteral nutrition is administered in a natural or synthesized manner to the gastrointestinal tract orally or through a tube, parenteral nutrition is administered directly into the blood. This means nutrients are administered in a purely chemical form, which is more direct and effective but causes more complications.
What eating habits are advised to prevent cancer? Does the consumption of alcohol affect the chances of developing cancer?
There is no miracle diet that can 100% guarantee the prevention of cancer. Nevertheless, certain eating habits are recommended and are useful in the prevention of cancer. Amongst these is the regular consumption of foodstuffs like fruit and vegetables, fiber and blue fish. It is also recommended to keep one’s weight down with a balanced diet and regular exercise.
Furthermore, an excess of processed foods, simple sugars and saturated fats should be avoided. Alcohol should be consumed in moderation, as it increases the risk of cancer of the mouth, larynx, pharynx, esophagus, liver and breast. Recommended doses do not exceed two units daily for men and one unit daily for women, bearing in mind that one unit equals 355 ml of beer or 150 ml of wine, for instance.