Abstract
Cancer-related fatigue is a subjective and pervasive symptom, related to the disease and its treatments, and has a significant impact on patients' quality of life. This study has two fundamental goals: (1) to identify different fatigue trajectories in metastatic colorectal cancer patients undergoing chemotherapy; (2) to identify psychosocial determinants of these fatigue trajectories. A total of 169 patients were assessed for their level of fatigue at the beginning of a new chemotherapy cycle, and were subsequently followed every two weeks. Psychosocial variables such as anxiety, depression, perceived control, coping strategies, and social support were measured from the start. Four trajectories of physical fatigue were identified: 1) a trajectory of "intense fatigue" (6.51%), 2) a trajectory of "average fatigue" (48.52%), 3) an "increasing fatigue" trajectory over time characterized by non-fatigued patients at the inclusion (11.83%); finally, 4) a trajectory of resilient patients who report "no fatigue" during treatment (33.14%). While it appears that physical fatigue and depression are strongly associated, the results also show that poor adaptation (emotionally-focused coping) and little control over the evolution of the disease contribute to the intensity and the increase of fatigue over time.The identification of transactional variables in the explanation of this symptom makes it possible to envisage adapted psychosocial care, turned towards personalized medicine.