ReviewIncidence and Correlates of Fatigue in Metastatic Castration-Resistant Prostate Cancer: A Systematic Review

Prostate cancer is the second most common malignancy of men in the western countries. Fatigue is the most stressful symptom of which patients with metastatic castration-resistant prostate cancer (mCRPC) complain. The aim of this article was to report available data about the incidence of fatigue in mCRPC and its correlates. The design involved a systematic review to define incidence of fatigue according to Common Toxicity Criteria in randomized controlled trials of medical treatments of mCRPC and according to International Classification of Diseases Revision 10 (ICD-10) criteria, and to define prevalence and correlates of fatigue in patients with mCRPC. The data source used was PubMed. In December 2014, 2 PubMed searches were performed and the clinical data on the occurrence of cancer-related fatigue along the course of metastatic disease, and findings about its pathogenesis were summarized. Cancer-related fatigue, as defined according to ICD-10 criteria, was reported in 12% to 21% of patients, and prospective clinical trials showed a prevalence of Grade 3/4 fatigue according to Common Toxicity Criteria of 0% to 18%. A list of possible correlates of fatigue in mCRPC, either patient-related, disease-related, or treatment-related, is proposed herein for future studies. Antineoplastic treatments, particularly chemotherapy and radiotherapy, have a major role in the pathogenesis of fatigue in metastatic prostate cancer, however, hormonal treatments remain the most prevalent therapies. A standardized tool for multidimensional assessment of fatigue in metastatic cancer is suggested.