Course of fatigue between two cycles of adjuvant chemotherapy in breast cancer patients

The purpose of this study was to determine the course of fatigue in patients with breast cancer between 2 cycles of adjuvant chemotherapy, from the day of administration until the day of the next infusion. In a prospective cohort study, a sample of 151 patients with breast cancer receiving adjuvant chemotherapy was recruited from 6 hospitals in mainly the south of the Netherlands. Patients reported their experience of fatigue in a diary, the Shortened Fatigue Questionnaire, on a daily basis between the third and fourth treatment with adjuvant chemotherapy. Patients were treated with either a doxorubicin containing schedule or with cyclophosphamide, methotrexate, and 5-fluorouracil (CMF, 28 days). In the 28-day regimens, infusions were given on day 1 and day 8. The days after completion of the third and the start of the fourth treatment with chemotherapy were statistically analyzed. We tested the hypothesis that the maximum fatigue score occurs in the first 4 days after treatment. The mean age of the sample was 47.2 years (SD = 8.8). Most women (84%) were married or lived together with a partner. The majority (80%) of all patients had been diagnosed with stage II breast cancer. The division between mastectomies (47%) and lumpectomies (52%) was approximately equal. Sixty percent of the patients received radiotherapy before the third treatment with chemotherapy and/or in the period they kept the diary. A chaotic pattern of fatigue between the 2 cycles of chemotherapy emerged. Smooth (splines) curves showed an average highest level of fatigue on day 3 from the start. For the 28-day regimens, another distinct peak was seen around day 11. A relatively larger number of patients experienced peak fatigue levels before day 5. The course of fatigue in the CMF group was significantly different compared with the doxorubicin regimens. The fatigue peak in the CMF group was lower. Women taking cyclophosphamide orally experienced the peak level of fatigue significantly later. Influences of other variables were not observed in any chemotherapy group. Cancer-related fatigue has a chaotic nature. The first days after treatment with chemotherapy are the worst. The type of chemotherapy has a significant impact on the course of fatigue. Improved understanding of the nature and course of fatigue could equip healthcare providers better for informing patients about what they may expect. Future research should include interventions aimed at reducing or coping with fatigue.