The incidence of postoperative frailty is notably high among patients with colorectal cancer. Numerous studies have established a strong association between frailty and adverse outcomes, including postoperative complications and mortality. Given that frailty is a dynamic process, there is a scarcity of research exploring its occurrence and progression in colorectal cancer patients.

To investigate the developmental trajectory of postoperative frailty in patients with colorectal cancer and identify its influencing factors through a longitudinal research approach and to provide a theoretical basis for managing frailty in this population.

We employed a convenience sampling method to select patients with colorectal cancer from Jiangsu Provincial People's Hospital between July and December 2022. Data on general information and relevant factors were collected from the participants. The Tilburg Frailty Scale was utilized to assess frailty at four intervals: preoperatively, and then at 1 month, 3 months, and 6 months post-surgery. The growth mixture model was constructed to delineate the developmental trajectory of postoperative frailty and Logistic regression was used to analyze the factors influencing frailty in colorectal cancer patients.

A total of 374 patients completed the survey. By fitting the frailty data at four time points, results showed three optimal trajectory models: Health Improvement Type (n=305, 81.5%), Frailty Improvement Type (n=25, 6.7%), and Frailty Persistence Type (n=44, 11.8%). For clinical relevance, the latter two types were merged into a "Frailty Heterogeneity Trajectory". Multivariate Logistic regression analysis revealed several influencing factors for the frailty heterogeneity trajectory: age (OR=1.141, 95%CI=1.065-1.223), nutritional score (OR=0.424, 95%CI=0.303-0.594), number of comorbidities (OR=2.884, 95%CI=1.158-7.184), neoadjuvant therapy (OR=29.510, 95%CI=5.511-158.007), stoma establishment (OR=37.313, 95%CI=8.604-161.819), postoperative chemoradiotherapy (OR=95.071, 95%CI=17.664-511.674), depression level (OR=2.673, 95%CI=1.336-5.350), and social support (OR=0.881, 95%CI=0.797-0.974) (P<0.05) .

Postoperative frailty in patients with colorectal cancer demonstrates three distinct developmental trajectories: "Health Improvement Type""Frailty Improvement Type", and "Persistent Frailty Type". Healthcare professionals should identify the heterogeneous trajectory groups early on, particularly the latter two types, and implement targeted interventions to enhance their long-term health outcomes.