Docetaxel-related fatigue in men with metastatic prostate cancer: a descriptive analysis

Fatigue is a prevalent and debilitating side effect of docetaxel chemotherapy in metastatic prostate cancer. A better understanding of the kinetics and nature of docetaxel-related fatigue may provide a framework for intervention. This secondary analysis was performed using the MOTIF database, from a phase III, randomised, double-blind, placebo-controlled study of modafinil (200 mg/day for 15 days) for docetaxel-related fatigue in men with metastatic prostate cancer [1]. The pattern of fatigue was analysed using the MDASI (MD Anderson Symptom Inventory) score. The impact of modafinil, cumulative docetaxel exposure, age and smoking status on fatigue kinetics were explored. Fatigue-related symptoms were assessed using the SOMA6 (fatigue and related symptoms) subset of the SPHERE (Somatic and Psychological Health Report). Mood was tracked using the short form 36 health survey questionnaire (SF-36). Across four docetaxel cycles, fatigue scores were higher in the first week and decreased over weeks two and three. Whilst men randomised to modafinil had reduced fatigue scores, cumulative docetaxel had little impact. Younger men (55–68 years) had significantly reduced fatigue scores, whereas current and ex-smokers had higher scores. There was no significant change in mood status or haemoglobin across treatment cycles. Men described both ‘somnolence’ and ‘muscle fatigue’ contributing significantly to their symptom complex. Assessment and management of docetaxel-related fatigue remains an important challenge. Given the complex, multifactorial nature of fatigue, identification through structured interview and interventions targeted to specific ‘at risk’ groups may be the most beneficial. Understanding the temporal pattern (kinetics) and nature of fatigue is critical to guide this process.