Fatigue is an exceedingly common often treatable problem in cancer patients that profoundly affects all aspects of quality of life. Prevalence estimates have ranged from 50% to 90% of cancer patients overall. After addressing reversible or treatable contributing factors, such as hypothyroidism, anemia, sleep disturbance, pain, emotional distress, climacterium, medication adverse events, metabolic disturbances, or organ dysfunction such as heart failure, myopathy, and pulmonary fibrosis, patients may be screened with a brief fatigue self-assessment tool. All cancer patients should be screened regularly for fatigue. Those with moderate or severe fatigue may benefit from both pharmacologic and nonpharmacologic interventions, while mild fatigue that does not interfere with quality of life can be treated with nonpharmacologic measures alone. Physicians often have insufficient knowledge about fatigue and its treatments or underestimate the impact of fatigue on quality of life, while patients may consider it an unavoidable and untreatable side-effect and fear that reporting it may incite a change toward less aggressive cancer treatment. A practical review may therefore be useful to health care professionals in order to avoid the common barriers to its treatment that exist on the sides of both physicians and patients.

Guarana is an effective, inexpensive, and nontoxic alternative for the short-term treatment of fatigue in BC patients receiving systemic chemotherapy. Further studies are needed to confirm these results and to evaluate their generalizability to chronic CRF and to other types of cancer.

Type II deiodinase (D2) activates thyroid hormone by converting thyroxine (T4) to 3,5,3′-triiodothyronine (T3). This allows plasma T4 to signal a negative feedback loop that inhibits production of thyrotropin-releasing hormone (TRH) in the mediobasal hypothalamus (MBH) and thyroid-stimulating hormone (TSH) in the pituitary. To determine the relative contributions of these D2 pathways in the feedback loop, we developed 2 mouse strains with pituitary-and astrocyte-specific D2 knockdown (pit-D2 KO and astro-D2 KO mice, respectively). The pit-D2 KO mice had normal serum T3 and were systemically euthyroid, but exhibited an approximately 3-fold elevation in serum TSH levels and a 40% reduction in biological activity. This was the result of elevated serum T4 that increased D2-mediated T3 production in the MBH, thus decreasing Trh mRNA. That tanycytes, not astrocytes, are the cells within the MBH that mediate T4-to-T3 conversion was defined by studies using the astro-D2 KO mice. Despite near-complete loss of brain D2, tanycyte D2 was preserved in astro-D2 KO mice at levels that were sufficient to maintain both the T4-dependent negative feedback loop and thyroid economy. Taken together, these data demonstrated that the hypothalamic-thyroid axis is wired to maintain normal plasma T3 levels, which is achieved through coordination of T4-to-T3 conversion between thyrotrophs and tanycytes.

Cancer-related fatigue is the most prevalent cancer symptom, reported in 50%-90% of patients and severely impacts quality of life and functional capacity. The condition remains underreported and often goes untreated. Guidelines suggest screening for fatigue at the initial visit, when the diagnosis of advanced disease is made, and at each chemotherapy session, as well as the identification of treatable contributing factors such as anemia, hypothyroidism, depression and sleep disorders. Brief assessment tools such as the Brief Fatigue Inventory or the Visual Analog Scale may be appropriate in the initial scoring of fatigue severity, but the initial approach to treatment usually requires a more comprehensive assessment, education, and the determination of an individualized treatment plan. Patients with moderate or severe fatigue may benefit from both pharmacological and non-pharmacological interventions, whereas mild fatigue that does not interfere with quality of life can be treated with non-pharmacological measures alone. Non-pharmacological measures that have shown to be promising include cognitive-behavioral interventions such as energy conservation and activity management (ECAM), exercise and perhaps sleep therapy. Many other modalities may be beneficial and can be used on an individual basis, but there is insufficient evidence to promote any single treatment. Pharmacological therapies that have shown to be promising include the psycho-stimulants methylphenidate and dexmethylphenidate, modafinil (in severely fatigued patients only), and erythropoietin-stimulating agents in patients with chemotherapy-associated anemia and hemoglobin levels < 10 g/dL. Recently, our group reported impressive results with the use of the dry extract of Guarana (Paullinia cupana), with no significant side effects and at low cost, for the treatment of physical and mental cancer-related fatigue.

We were unable to show that patients with breast cancer undergoing radiation therapy derive any advantage with guaraná over placebo for both fatigue and depressive symptoms.