- Week 14: second visit. Patients will be invited to come to the Luxembourg Institute of Health (Strassen, Luxembourg). During this second visit (duration: 70 min), patient will fill in the EORTC-QLQ30 questionnaire and the cost questionnaire (please see details of this questionnaire in the "Cost-effectiveness of the intervention" section). Height and weight will be measured. Patients will perform the same physical fitness tests as during the first visit (ramped Bruce protocol on a treadmill, leg strength and grip strength). Patients will be handed out the accelerometer to be worn during one week to evaluate their physical activity behaviour.