Preoperative Weight Loss in Patients With Excess Weight and Colorectal Cancer: The CARE Feasibility Randomized Clinical Trial.

IMPORTANCE: Excess weight increases morbidity risk after colorectal cancer surgery. OBJECTIVE: To assess the feasibility of a preoperative weight loss intervention. DESIGN, SETTING, AND PARTICIPANTS: CARE was an assessor-blinded randomized clinical trial performed between March 27, 2023, to August 13, 2024, with a 30-day postoperative follow-up in adults with a body mass index of 28 or greater who were awaiting curative elective colorectal cancer resection at 8 hospitals across England. INTERVENTION: Dietetic support with a low-energy (800 kcal/d, 76 g/d of protein) total diet replacement program between decision to treat and surgery. MAIN OUTCOMES AND MEASURES: Progression criteria for a definitive trial included recruitment (≥72 patients), engagement (≥75% of dietetic telephone calls attended), adherence (≥60% of intervention participants achieving ≥5% weight loss), and retention (≥85%). Secondary outcomes included morbidity, symptoms, and changes in weight and fat-free mass. Outcomes were modeled during a 30-year time horizon using cohort simulation. RESULTS: Of the 150 potentially eligible participants approached, 71 eligible randomized participants (mean [SD] age, 64 [8.7] years; 43 [61%] male; mean [SD] body mass index, 35.4 [5.4]) undergoing surgery (36 in the intervention group and 35 in the usual care group) were included in the analysis. Participants were accrued at a rate of 0.57 participants per site per month compared with the anticipated rate of 0.75. Participants attended 85% of their dietetic calls. The median (IQR) period from randomization to surgery was 33 (25-43) days, during which 22 (61%) of the intervention participants and 3 (9%) of the usual care participants lost 5% or more of their weight (odds ratio, 16.8; 95% CI, 4.3-65.3). Intervention participants lost a mean (SD) of 6.1 (3.0) kg before surgery, which was 4.3 kg (95% CI, 2.7 to 5.8 kg) more than the usual care participants. Between-group adjusted change in fat-free mass was 0.1 kg (95% CI, -3.9 to 4.0 kg). There was no evidence of a difference between the 2 group in the proportion of patients with any complications (14 [39%] vs 14 [40%]) or with Clavien-Dindo grade I, II, or III complications. Fecal incontinence (-8.6 points [95% CI, -16.7 to -0.5 points]) and sore skin (-15.9 points (95% CI, -25.3 to -6.6 points]) improved postoperatively in the intervention compared with usual care group. There were no intervention-related serious adverse events. Retention was 100%. In an exploratory observational analysis, participants who lost 3.2% or more of their body weight (above the median loss) had a 50% relative reduction in complications (95% CI, 1%-78%). Modeling indicated that the intervention was cost-effective. CONCLUSIONS AND RELEVANCE: This randomized clinical trial's intervention of low-energy total diet replacement before colorectal cancer resection was feasible and well tolerated, lacked safety concerns, and was likely cost-effective. The progression criteria were met, but some recruitment challenges need to be addressed. TRIAL REGISTRATION: ISRCTN.org Identifier: ISRCTN39207707.