Cancer-related fatigue: can it be due to adrenal suppression secondary to high-dose steroids used as antiemetic?

Abstract

To the editor: The use of dexamethasone for cancer-related fatigue (CRF) in patients with advanced cancer is a controversial issue. Beneficial effects of dexamethasone may be counterbalanced by its serious side effects. The exact mechanism of the action of steroids on cancer-related fatigue is unknown. Recently, Yennurajalingam et al. hypothesized that dexamethasone exerts its effects on CRF mainly by interfering with the peripheral effects of proinflammatory cytokines [1]. We believe that this may not be the case for some of patients with CRF. The exact pathogenesis of CRF is unknown. A role of systemic inflammation or imbalance between hypothalamicpituitary-adrenal (HPA) axis and systemic cytokines has been proposed [2, 3]. Advanced stage cancer represents a state of chronic stress. Low levels of endogenous cortisol, which may be associated with symptoms in advanced cancer, had been demonstrated by Lundstrom et al. [4]. Major symptoms of adrenal insufficiency (i.e., fatigue, nausea, loss of appetite) may be misinterpreted as CRF. Indeed, some patients treated for CRF may have unrecognized adrenal insufficiency. High dose of dexamethasone (8–16 mg/day) is commonly used as antiemetic therapy in highly and moderately emetic regimens. Updated ASCO guidelines on antiemetics recommend a 4-day course of dexamethasone (12 mg on day 1 and 8 mg on days 2–4) for highly emetogenic chemotherapy and 1–3-day 8 mg course for moderately emetogenic chemotherapy [5]. Highdose steroids may suppress the hypothalamic pituitary and adrenal axis, even with short-term use [6]. Han et al. published their article on adrenal suppression related to the use of dexamethasone as an antiemetic therapy in patients with cancer in July 2012 [7]. Patients receiving dexamethasone as an antiemetic for at least 3 days per cycle and for more than 3 months were included in this study. Adrenal suppression was demonstrated biochemically in 45 of the 103 patients (43.7 %). Adrenal suppression was more common in patients receiving megestrol acetate concomitantly. Daily replacement therapy with 7.5–10 mg of prednisolone for 1–2 weeks in patients with suppressed HPA axis resulted in the improvement of symptoms associated with adrenal insufficiency. This dose of prednisolone is approximately equivalent to 1 mg of dexamethasone [8]. This is about one eighth of the dose recommended in the study of Yennurajalingam et al. We believe that this lower dose may allow the use of steroid for longer periods and spare some of the patients with CRF from serious side effects of higher doses of steroids. Metabolic (i.e., hyperglycemia, hypokalemia) and muscular side effects (i.e., proximal muscle weakness) of long-term use of steroids may be confused with CRF or even increase the severity of CRF. Lower dexamethasone dose will probably cause less metabolic and muscular side effects. For those patients with continuing symptoms of CRF, steroid dose may be gradually increased. In the current study, no follow up for the quality of life was made after cessation of dexamethasone [1]. As CRF is a chronic problem, symptoms may become worse after cessation of high-dose dexamethasone. Lesser dose of dexamethasone may be used more safely for longer periods of time for some patients with this chronic problem. There are still unanswered questions about CRF: What should be done for patients without biochemical evidence of HPA axis suppression? Should we search for biochemical evidence of inflammation (i.e., C-reactive protein) in this group of patients? Should we start with higher doses of dexamethasone when we have laboratory evidence of both systemic inflammation and HPA axis suppression? Should adrenal insufficiency be in the routine checklist of evaluation O. O. Eren (*) :B. Oyan Medical Oncology Section, Department of Internal Medicine, Yeditepe University Hospital, Devlet yolu, Ankara Caddesi, 102-104 Istanbul, Turkey e-mail: droneren@hotmail.com