Patients with kidney cancer and many other types of cancer have in common chronic fatigue as one of the main symptoms, especially as the tumor grows larger and starts causing changes to the metabolism of energy. Chronic fatigue results from a complex interaction of triggering factors, including nutrient deficiencies, anemia, an increase in energy expenditure, and metabolic stress.
Nutrient deficiencies result from appetite changes and nutrient absorption problems; they are usually associated with anemia, which is a common cause of chronic fatigue in kidney cancer. At the same time, the tumor itself has increased energy expenditure as it needs extra energy to keep growing. In the process, cancer cells take away oxygen and nutrients meant to nourish normal cells and contributes to a reduction in perceived levels of energy. At the same time, cancer and chronic disease put the body in metabolic stress, which also contributes to the development of fatigue.