Objective: Fatigue is a multidimensional symptom that is described in terms of perceived energy, mental capacity, and psychological status: it can impair daily functioning and lead to negative effects on quality of life. It is one of the most common side effects of chemotherapy and radiotherapy. In recent studies, l-carnitine (LC) supplementation has been demonstrated to be able to improve fatigue symptoms in patients with cancer.
Methods: In the present study we tested the efficacy and safety of LC supplementation in a population of patients who had advanced cancer and developed fatigue, high blood levels of reactive oxygen species, or both. As outcome measures we evaluated fatigue and quality of life in relation to oxidative stress, nutritional status, and laboratory variables, mainly levels of reactive oxygen species, glutathione peroxidase, and proinflammatory cytokines. From March to July 2004, 12 patients who had advanced tumors (50% at stage IV) at different sites were enrolled (male-to-female ratio 2:10, mean age 60 y, range 42-73). Patients were only slightly anemic (hemoglobin 10.9 g/dL) and hemoglobin levels did not change after treatment. LC was administered orally at 6 g/d for 4 wk. All patients underwent antineoplastic treatment during LC supplementation.
Results: Fatigue, as measured by the Multidimensional Fatigue Symptom Inventory-Short Form, decreased significantly, particularly for the General and Physical scales, and for quality of life in each subscale of quality of life in relation to oxidative stress. Nutritional variables (lean body mass and appetite) increased significantly after LC supplementation. Levels of reactive oxygen species decreased and glutathione peroxidase increased but not significantly. Proinflammatory cytokines did not change significantly.
Conclusion: Improvement of symptoms with respect to fatigue and quality of life in relation to oxidative stress may be explained mainly by an increase in lean body mass, which may be considered the most important nutritional or functional parameter in assessing the cachectic state of patients. In this view, fatigue with related symptoms can well be considered an important constituent of cancer-related anorexia cachexia syndrome.