Observational studies suggest that a healthy diet in combination with ample physical activity is associated with a lower prevalence of cancer-related fatigue. The SoFiT trial (SoFiT: Study on Fatigue: a lifestyle intervention among colorectal cancer survivors) will assess the effect of a personalized lifestyle program on cancer-related fatigue in a randomised study.

We designed a program that aims to increase adherence to lifestyle recommendations on diet and physical activity. The program was person-centred with regards to the lifestyle and personal characteristics of participants, to the determinants of behaviour of that participant, and to the preference, opportunities, and barriers of the participant.

The effect of the program was tested in the SoFiT trial: a two-armed, parallel, randomized controlled trial among adult stage I-III colorectal cancer survivors, who experience cancer-related fatigue after treatment completion; intended sample size n=184. Participants randomized to the intervention group received the personalized lifestyle program. During six months, participants in the intervention group had individual sessions with a lifestyle coach of which four sessions were face-to-face and eight sessions were remote. After six months, participants randomized to the control group had access to two lifestyle coaching sessions and to the same materials that the intervention group also received.

The primary endpoint of the trial is cancer-related fatigue. Secondary endpoints are: sleep quality and duration, health-related quality of life, physical performance, depression and anxiety, skeletal muscle echo intensity and cross-sectional area, and gut microbiota composition.

This trial will show the effects of a personalized lifestyle program on cancer-related fatigue, and on an extensive set of secondary outcomes.