Course of mental fatigue and motivation in breast cancer patients receiving adjuvant chemotherapy

Background: The purpose of this study is to determine the course of fatigue referring to cognitive symptoms (scale 'mental fatigue') as well as the motivation to start any activity (scale 'reduced motivation'), as a function of chemotherapy, in breast cancer patients undergoing adjuvant chemotherapy. Patients and methods: In a prospective cohort study a sample of 157 patients with breast cancer was interviewed at the first, third and fifth cycle of adjuvant chemotherapy as well as 4 and 12 weeks after completion of adjuvant chemotherapy. Patients were treated with standard adjuvant chemotherapy, either a doxorubicin containing schedule or CMF (cyclophosphamide, methotrexate and fluorouracil). The psychological dimensions of fatigue were measured by the Multidimensional Fatigue Inventory. A linear multilevel model was used for analysing the courses. Results: The course of mental fatigue and motivation were not affected by the type of chemotherapy. The course of mental fatigue and motivation varied, but seemed to be stable during the treatment of chemotherapy. After the completion of chemotherapy, a weak improvement was seen. Relatively many patients experienced depressive symptoms during the study. These symptoms were correlated with both dimensions of fatigue. At all measurements mental fatigue was influenced by type of operation where women with a mastectomy were significantly more mentally fatigued than women that had undergone a lumpectomy, but nevertheless they were significantly more motivated to start any activity. Age, marital status, number of treatments and the interval between the operation and the first treatment of chemotherapy also seemed to be important determinants. Conclusions: An unequivocal pattern of mental fatigue and reduced motivation during as well as after adjuvant chemotherapy was not found. Depressive symptoms were definitely related to these variables. Type of operation had a significant impact on mental fatigue and motivation to start any activity. Health care providers should be aware of the high rate of patients who experience depressive symptoms during and after the treatment of chemotherapy. Further research should include the trajectory preceding adjuvant chemotherapy and a longer study period afterwards. Moreover, the exact influence of the variables 'age', 'marital status', 'number of treatments' and 'the interval between the operation and the first treatment of chemotherapy' on fatigue is unclear and needs further study.