Long-Term Functional Outcomes After Prehabilitation in Frail Older Adults Undergoing Colorectal Cancer Surgery: A One-Year Prospective Cohort Study

Background: Frailty is associated with adverse postoperative outcomes and functional decline in older adults undergoing colorectal cancer (CRC) surgery. The long-term course of frailty and functional outcomes among patients undergoing prehabilitation before CRC surgery remains insufficiently investigated. Methods: This prospective observational cohort study evaluated long-term functional and physiological outcomes in older adults with frailty syndrome undergoing colorectal cancer (CRC) surgery who participated in a structured prehabilitation program. Forty-one patients aged >70 years were assessed before prehabilitation and at one-year follow-up. Frailty (the Clinical Frailty Scale [CFS] and the 5-item Frailty Index [5-FI]), physical activity, postural function, respiratory parameters, and functional performance (the 6 min walk test [6MWT] and the Timed Up and Go [TUG] test) were evaluated. Results: Of the 93 eligible patients, 41 completed the one-year follow-up and were therefore included in the final analysis. A small but statistically significant increase in frailty was observed using 5-FI (mean difference = 0.029, p = 0.012), with no significant change in CFS. Postural function improved (p = 0.031), while physical activity and functional performance remained stable (6MWT: 392.71 vs. 384.36 m, p = 0.885; TUG: 12.36 vs. 10.42 s, p = 0.051). A significant reduction in pre- and post-exercise oxygen saturation was observed; however, the magnitude of change (before: −1.25%, p = 0.006; after: −0.91%, p < 0.001) was small and of uncertain relevance. Conclusions: Over a one-year follow-up of prehabilitated CRC patients with frailty, their functional performance remained stable despite a subtle progression of frailty. These findings suggest a dissociation between physiological vulnerability and functional status. Due to the observational design of the study and the lack of a control group, the results should be interpreted as descriptive rather than causal.