Effect of exercise on memory function and daily activities after colorectal cancer surgery: an exploratory secondary analysis from the randomised trial PHYSSURG-C.

OBJECTIVES: To explore the effect of a short-term unsupervised exercise intervention on memory function and activities of daily living after surgery for colorectal cancer. DESIGN: Secondary analysis within a randomised controlled open label trial with central computerised 1:1 parallel allocation. SETTING: One university and five regional hospitals in Sweden. Recruitment period 2015-2020. INTERVENTION: Moderately intense aerobic physical activity 30 minutes a day, 2 weeks before and 4 weeks after surgery. PARTICIPANTS: Patients with colorectal cancer undergoing elective curative surgery. Of the 761 randomised, 631 completed the study and were analysed (intervention 296/379, control 335/382). Median age 70 years, 61% men. OUTCOME MEASURES: Self-reported memory function and activities of daily living. Questionnaires were distributed at inclusion and at 4 weeks and 12 months postoperatively. RESULTS: There was no difference in self-reported memory function between the groups at 4 weeks. At 12 months, participants in the intervention group were less likely to report being told they had poor memory (OR 0.61, 95% CI 0.38 to 0.98). Regarding daily activities, participants in the intervention group were more likely to report a greater ability to shop for food or other necessities at 4 weeks (OR 1.53, 95% CI 1.07 to 2.20). No other significant differences were seen. CONCLUSION: This exploratory study with secondary data, nested in a multicentre randomised trial, found no substantial effects of a short-term unsupervised exercise intervention on memory function or the ability to perform daily activities in patients with colorectal cancer. An exercise intervention of this duration and intensity could be insufficient for improvement compared with standard care. TRIAL REGISTRATION NUMBER: NCT02299596.