Simple SummaryColorectal cancer (CRC) patients often experience fatigue, poor ability to work, and low quality of life (QoL) after therapy. We conducted a prospective study of 147 CRC patients who underwent a three-week in-patient rehabilitation clinic visit in Germany. Patients completed questionnaires at the start of rehabilitation and at regular 3-month intervals for up to a year. We found a strong correlation between fatigue and QoL, and moderate correlations between fatigue and the ability to work, as well as between QoL and the ability to work. Fatigue, QoL, and ability to work improved significantly from the start of rehabilitation to the three-month follow-up, and there was little change afterward in the first year after rehabilitation. In summary, fatigue, QoL, and the ability to work were highly interconnected in CRC patients, and all of them improved from the start of rehabilitation to the 3-month follow-up.AbstractCancer-related fatigue, low quality of life (QoL), and low ability to work are highly prevalent among colorectal cancer (CRC) patients after tumor surgery. We aimed to analyze their intercorrelations and trajectories in the first year after in-patient rehabilitation in the German multicenter MIRANDA cohort study. Recruitment is ongoing, and we included the first 147 CRC patients in this analysis. Participants filled out questionnaires at the beginning of in-patient rehabilitation (baseline) and at 3, 6, 9, and 12 months after the baseline. The EORTC-QLQ-C30-General-Health-Status (GHS)/QoL, the FACIT-F-Fatigue Scale, and the FACIT-F-FWB-ability-to-work items were used to evaluate QoL, fatigue, and ability to work, respectively. The fatigue and QoL scales were highly correlated (r = 0.606). A moderate correlation was observed between the fatigue and ability to work scales (r = 0.487) and between the QoL and ability to work scales (r = 0.455). Compared to the baseline, a statistically significant improvement in the QoL, ability to work, and fatigue scales were observed at the 3-month follow-up (Wilcoxson signed rank test, allp< 0.0001). The three scales plateaued afterward until the 12-month follow-up. In conclusion, fatigue, QoL, and ability to work were highly interrelated, improved quickly during/after in-patient rehabilitation, and did not change much afterward in German CRC patients.