Multicentre, prospective, observational cohort study with a follow up time of one year. After initial diagnosis of CRC subjects will be screened for frailty using validated questionnaires, physical tests and non-invasive measurements. Frailty characteristics and HRQL are determined by Geriatric 8 (G8), Hospital Anxiety and Depression Scale(HADS), Euroqol- 5 dimensional (EQ-5D), Lawton Instrumental Activity of Daily Living scale(IADL), Mini Nutrition Assessment (MNA), 6 Item Cognitive Impairment Test (6-CIT), Identification of Seniors At Risk - Hospitalized Patients(ISAR-HP) and the EORTC-QLQ-C30/CR29 (HRQL in CRC patients). Physical tests include the Timed to Get Up (TUG) test and the hand grip strength test. Furthermore, the non-invasive measurements consist of a sarcopenia analysis using an existing CT/MRI scan and measurement of Advanced Glycation Endproducts (AGE reader).

Additional patients characteristics including medication use, medical history, tumor characteristics, neoadjuvant therapy and laboratory results of preoperative routine blood sampling will be collected. At three, six and twelve months after diagnosis, EORTC QLQ-C30/EORTC QLQ-CR29 and EQ-5D questionnaires are used to determine HRQL and disability free survival.