Relationship between fatigue and cytokine levels in patients age 50+ with acute myeloid leukemia (AML)

Abstract

19566 Background: Fatigue is the most common and disabling symptom affecting patients with AML; effective prevention or treatment measures have yet to be found. Cytokines, biological markers of inflammation, may represent a major cause of fatigue, but published data are limited. Methods: Patients age 50 or older with AML were recruited between May and September 2006. All patients were fluent in English, within one year of diagnosis, and free of any other active malignancy. Fatigue was measured using the Functional Assessment of Cancer Therapy (FACT) Fatigue subscale, a single-item global fatigue scale, and the European Organization for the Research and Treatment of Cancer (EORTC) QLQ-C30. Blood was simultaneously drawn for quantitative measurement of a panel of 13 cytokines. Repeat measurements were done 4–6 weeks later. Correlational analysis was used to examine relationships between individual cytokines and fatigue scores. Changes in fatigue scores between time points were correlated with changes in cytokine levels. Results: 34 patients (23 men; 11 women) were enrolled (mean age 67 y; range 52–84). 27% had not started chemotherapy or were receiving best supportive care, while the rest were undergoing active chemotherapy. At baseline, a weak correlation (r=0.332, p=0.059) was seen with interleukin (IL)-6 and at least one fatigue measure. No correlations (r<0.30) were observed with any of the other cytokines (interferon (IFN)-?, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IP-10, MCP-1, MiG, and tumor necrosis factor-a) and any fatigue measure. Follow-up data were available for 29 patients. A statistically significant correlation with fatigue was seen with IL-2 (r=0.407, p=0.032), and clinically-important correlations that did not achieve conventional statistical significance were seen with IFN-? (r=0.331, p=0.085), IL-5 (r=0.344, p=0.073), and IL-10 (r=0.326, p=0.091). Conclusions: Based on these data, the most promising cytokine-fatigue relationship was noted with IL-2. However, IFN-?, IL-5, IL-6, and IL-10 also showed potentially important relationships with fatigue. Given our small sample size and patient enrolment at differing time points during their treatment course, further controlled studies are warranted. No significant financial relationships to disclose.