Factors predicting clinically significant fatigue in women following treatment for primary breast cancer

Abstract

Cancer-related fatigue is common, complex, and distressing. It affects 70-100% of patients receiving chemotherapy and a significant number who have completed their treatments. We assessed a number of variables in women newly diagnosed with primary breast cancer (BrCa) to determine whether biological and/or functional measures are likely to be associated with the development of clinically significant fatigue (CSF). Two hundred twenty-three women participated in a study designed to document the impact of the diagnosis and treatment of primary breast cancer on function. Forty-four had complete data on all variables of interest at the time of confirmed diagnosis but prior to treatment (baseline) and ≥9 months post-diagnosis. Objective measures and descriptive variables included history, physical examination, limb volume, hemoglobin, white blood cell count, and glucose. Patient-reported outcomes included a verbal numerical rating of fatigue (0-10, a score of ≥4 was CSF), five subscales of the SF-36, Physical Activity Survey, and Sleep Questionnaire. At baseline, the entire cohort (n=223) and the subset (n=44) were not significantly different for demographic, biological, and self-reported data, except for younger age (p=0.03) and ER+ (p=0.01). Forty-five percent had body mass index (BMI)≥25, 52% were post-menopause, and 52% received modified radical mastectomy, 39% lumpectomy, 52% chemotherapy, 68% radiation, and 86% hormonal therapy. Number of patients with CSF increased from 1 at baseline to 11 at ≥9 months of follow-up. CSF at ≥9 months significantly correlated with BMI≥25, abnormal white blood cell count, and increase in limb volume and inversely correlated with vigorous activity and physical function (p<0.05). Fatigue increases significantly following the treatment of BrCa. Predictors of CSF include high BMI and WBC count, increase in limb volume, and low level of physical activity. These are remediable. © 2010 The Author(s).