Background: Older patients are at high risk of experiencing delayed functional recovery after surgical treatment. This study aimed to identify factors that predict changes in the level of support for activities of daily living and mobility 1 year after colonic cancer surgery.Methods: This was a multicentre, observational study conforming to STROBE guidelines. The prospective data included pre-and postoperative mobility and need for support in daily activities, co-morbidities, onco-geriatric screening tool (G8), clinical frailty scale (CFS), operative data, and postoperative surgical outcomes.Results: A total of 167 patients aged 80 years or more with colonic cancer were recruited. After surgery, 30 per cent and 22 per cent of all patients had increased need for support and decreased motility. Multivariableanalysis with all patients demonstrated that preoperative support in daily activities outside the home (OR 3.23, 95 per cent c.i. 1.06 to 9.80, P = 0.039) was associated with an increased support at follow-up. A history of cognitive impairment (3.15, 1.06 to 9.34, P = 0.038) haemoglobin less than 120 g/l (7.48, 1.97 to 28.4, P = 0.003) and discharge to other medical facilities (4.72, 1.39 to 16.0, P = 0.013) were independently associated with declined mobility. With functionally independent patients, haemoglobin less than 120 g/l (8.31, 1.76 to 39.2, P = 0.008) and discharge to other medical facilities (4.38, 1.20 to 16.0, P = 0.026) were associated with declined mobility.Conclusion: Increased need for support before surgery, cognitive impairment, preoperative anaemia, and discharge to other medical facilities predicts an increased need for support or declined mobility 1 year after colonic cancer surgery. Preoperative assessment and optimization should focus on anaemia correction, nutritional status, and mobility with detailed rehabilitation plan.Greater increased need for support before surgery, cognitive impairment, preoperative anaemia, and discharge to other medical facilities predicted an increased need for support or declined mobility 1 year after colonic cancer surgery. Preoperative assessment and optimization should especially focus on anaemia correction, nutritional status, and mobility with a detailed rehabilitation plan.</p
