Values of Sleep/wake, Activity/rest, Circadian Rhythms, and Fatigue Prior to Adjuvant Breast Cancer Chemotherapy

Fatigue is the most prevalent and distressing symptom experienced by patients receiving adjuvant chemotherapy for early stage breast cancer. Higher fatigue levels have been related to sleep maintenance problems and low daytime activity in patients who have received chemotherapy, but knowledge describing these relationships prior to chemotherapy is sparse. The Piper Integrated Fatigue Model guided this study, which describes sleep/wake, activity/rest, circadian rhythms, and fatigue and how they interrelate in women with Stage I, II, or IIIA breast cancer during the 48 hours prior to the first adjuvant chemotherapy treatment. The present report describes these variables in 130 females, mean age=51.4 years; the majority were married and employed. Subjective sleep was measured by the Pittsburgh Sleep Quality Index and fatigue was measured by the Piper Fatigue Scale. Wrist actigraphy was used to objectively measure sleep/wake, activity/rest, and circadian rhythms. Mean Pittsburgh Sleep Quality Index score was 6.73+/-3.4, indicating poor sleep. Objective sleep/wake results were within normal limits established for healthy individuals, except for the number and length of night awakenings. Objective activity/rest results were within normal limits except for low mean daytime activity. Circadian rhythm mesor was 132.3 (24.6) and amplitude was 97.2 (22.8). Mean Piper Fatigue Scale score was 2.56+/-2, with 72% reporting mild fatigue. There were significant relationships between subjective and objective sleep, but no consistent patterns. Higher total and subscale fatigue scores were correlated with most components of poorer subjective sleep quality (r=0.25-0.42, P< or =0.005).