Background: Fatigue is one of the most common side effects of treatment for breast cancer (BC). This study used a daily diary approach to investigate the course of fatigue in BC patients receiving adjuvant chemotherapy. We examined clinical (BSA, menopausal status, stage, hemoglobin levels) and self-reported biopsychosocial factors (anxiety, depression, pain, physical and social functioning) as predictors of fatigue after chemotherapy infusion.

Methods: We enrolled 28 stage I (39%), II (50%), and III (11%) BC patients (mean age = 48.9 years, SD = 9.7) receiving standard adjuvant chemotherapy. Fatigue was assessed over 14 consecutive days (day −2 to +11) using a modified version of the NIH Patient-Reported Outcomes Measurement Information System (PROMIS®) fatigue short-form. Putative predictors of fatigue were assessed in the week prior to infusion. Anxiety and depression were measured with computerized adaptive testing. Pain, physical functioning, and social functioning were assessed using PROMIS global health items. Clinical variables were abstracted from patients' medical records. Analyses used individual growth curve modeling to examine overall levels of post-infusion fatigue and rates of change (amplitude) in daily fatigue over a 14-day period prior to the next infusion.

Results: Daily fatigue varied considerably over the 14 day study period, following a sinusoidal pattern. Fatigue T-scores increased from near-normal values (mean = 53) by about 1 SD (p < .001) during the first 3 days post-infusion (mean = 62), peaked on days 3–6, and decreased to near-normal (mean = 53) by day 11. Higher baseline anxiety, depression, pain and problems with physical functioning independently predicted higher overall fatigue levels during the post-infusion period (p < .001). In addition, baseline pain and physical functioning predicted distinct patterns of change in fatigue scores (p < .05). Fatigue showed a steep rise and fall in patients with less pain and better physical functioning at baseline, rapidly returning to pre-infusion levels. Fatigue was more constant in patients with greater pain and worse physical functioning at baseline. These patients reported higher fatigue scores prior to infusion but experienced fewer dynamic changes in response to chemotherapy. Medical variables and social functioning were not associated with baseline fatigue levels or changes in fatigue.

Conclusions: This study demonstrates that BC patients with greater anxiety, depression, pain or poor physical functioning at baseline are at risk for prolonged and severe fatigue during treatment with chemotherapy. Patients with low pain and high physical functioning experience sharper changes in fatigue after infusion with quick return to baseline. The NIH PROMIS questionnaire provides a powerful quantitative method to identify predictors of chemotherapy-related fatigue. Identification of these predictors is critical for effective management of patient expectations and the development of targeted interventions to improve tolerance and functioning during adjuvant chemotherapy for breast cancer.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-08-06.