# Prehab before colorectal cancer surgery: walk-test signals and conflicting complication data

> Three sources report six-minute walk differences favouring prehabilitation, at varying certainty. Only one mixed-design meta-analysis reported fewer complications and shorter hospital stays.

AthleticsMD Clinical Desk · 2026-10-13 · https://blog.athleticsmd.org/prehab-before-colorectal-cancer-surgery-walk-test-signals-and-conflicting-compli

Prehabilitation is the effort to enhance a patient's physiological capacity before an operation in order to reduce the risk of treatment-related complications [1]. In colorectal cancer surgery the term usually means a multimodal programme. The Cochrane review defines this as at least two preoperative interventions, typically drawn from exercise, nutrition and psychological support [1, 2, 3]. The sources below are two meta-analyses, one Cochrane systematic review indexed in two versions, and the interim report of one randomised controlled trial (RCT) [1, 2, 3, 4, 5]. Three of them report six-minute walk differences favouring prehabilitation, with certainty ranging from moderate to very low. One reports no functional outcome in its abstract. They disagree on whether prehabilitation reduces complications or shortens hospital stay [1, 2, 3, 4, 5].

## Why the question matters

Surgical resection is the primary curative treatment for colorectal cancer, yet surgery itself can adversely affect patient health [1, 2]. Major colorectal surgery is associated with a 20 to 40% reduction in physiological and functional capacity and with higher fatigue 6 to 8 weeks after the operation [4]. Enhanced Recovery After Surgery (ERAS) programmes bundle several interventions around the operation and have improved outcomes substantially, but they are applied mainly in the perioperative and postoperative periods [2, 3]. Multimodal prehabilitation moves part of that effort into the weeks before surgery, with the stated aim of increasing resilience and thereby improving postoperative outcomes [2, 3].

## The sources and their designs

The five records differ in design, population, comparator and recency, and those differences shape how far each result can be trusted [1, 2, 3, 4, 5].

- The 2022 Cochrane systematic review searched databases in January 2021 and trial registries up to March 2021. It included only RCTs and pooled three trials with 250 adults with non-metastatic colorectal cancer scheduled for elective, mainly laparoscopic surgery in tertiary care centres [3].
- The 2023 record of the same Cochrane review reports the same search, the same three trials and the same effect estimates. It is indexed in the source list as a review rather than as a new systematic review [2, 3].
- The 2025 meta-analysis in the Journal of the American Geriatrics Society searched four databases up to August 5, 2023. It pooled 14 articles covering 2314 patients, drawing on RCTs, prospective studies and retrospective studies, and used a random-effects model [1].
- The 2025 meta-analysis in Techniques in Coloproctology pooled six RCTs and cohort studies with 547 elderly patients with colorectal cancer: 277 in intervention groups aged 65 to 78 years and 270 in control groups aged 66 to 82 years. Its authors judged the included studies to be at low risk of bias [5].
- The 2024 trial in Surgical Endoscopy is a single-centre, single-blind RCT. Its interim analysis covers 71 patients undergoing elective resection for colon cancer, with 35 randomised to four weeks of trimodal prehabilitation and 36 to no prehabilitation [4].

The Cochrane review rated the certainty of each estimate with GRADE, a structured framework for judging how confident one can be in pooled evidence [2, 3]. In its included trials, 130 participants received a four-week trimodal programme of exercise, nutritional intervention and anxiety reduction before surgery [2, 3]. They were compared with 120 participants who started an identical programme after surgery [2, 3]. That comparator isolates timing. By contrast, the 2024 trial compared prehabilitation with none, and the geriatric meta-analysis compared it with ERAS alone or ERAS plus postoperative rehabilitation [2, 3, 4, 5]. In the 2024 trial, both arms followed enhanced recovery programmes [4].

## Walking capacity: consistent direction, uneven certainty

Functional capacity in these studies is measured mainly with the 6-minute walk test (6MWT), reported as distance in metres [2, 3, 4, 5].

The Cochrane review gives the strongest RCT-only estimate. After prehabilitation and before surgery, it found a mean difference (MD) of 24.91 metres (95% CI 11.24 to 38.57; 3 studies; n = 225) [2, 3]. The authors described this difference as clinically relevant and rated it moderate certainty, downgraded for serious risk of bias [2, 3].

After surgery, the pooled Cochrane differences were less certain [2, 3]. At four weeks the MD was 26.02 (95% CI -13.81 to 65.85; 2 studies; n = 131), and at eight weeks it was 26.58 (95% CI -8.88 to 62.04; 2 studies; n = 140) [2, 3]. Certainty was low and very low respectively, because of risk of bias, imprecision and inconsistency, and both confidence intervals include no difference [2, 3]. The authors therefore concluded only that prehabilitation may result in improved functional capacity, preoperatively and postoperatively [2, 3].

The geriatric meta-analysis reported a statistically significant 6MWT mean difference of 18.3800 m in elderly patients (95% CI 1.5147 to 35.2453; p = 0.0404) [5]. Its abstract does not state at what time point the walk test was measured, so this estimate cannot be assigned to the preoperative or postoperative period [5]. Its I² statistic, a measure of how much results vary between studies beyond chance, was 3.7%, which the authors interpreted as low heterogeneity [5].

The 2024 interim trial reported larger differences [4]. Preoperatively, mean 6MWT distance was 96 m greater in the prehabilitation group (523 ± 24.6 vs 427 ± 25.3 m, p = 0.01) [4]. The difference was 103 m at 4 weeks after surgery (514 ± 89 vs 411 ± 115 m, p = 0.003) and 90 m at 8 weeks (531 ± 82 vs 441 ± 107 m, p = 0.008) [4]. These figures come from an interim analysis of 71 patients in which the control group received no prehabilitation rather than a matched postoperative programme [2, 3, 4]. The trial's postoperative differences were statistically significant, whereas the Cochrane postoperative intervals spanned values on both sides of no difference [2, 3, 4].

The abstract of the 14-article meta-analysis does not report a functional capacity outcome, so it neither supports nor contradicts these findings [1].

## Where the sources conflict: complications and length of stay

Only one source reported reductions in complications and hospital stay [1]. In the 14-article meta-analysis, which pooled randomised and non-randomised studies, multimodal prehabilitation was associated with a shorter length of stay (MD -2.47 days, 95% CI -3.56 to -1.39) [1]. It was also associated with a lower postoperative complication rate (odds ratio [OR] 0.74, 95% CI 0.59 to 0.94) and earlier first passage of flatus (MD -0.43 days, 95% CI -0.66 to -0.20) [1]. Its authors concluded that these benefits apply particularly in older populations, although the abstract does not report a separate estimate for older patients [1].

The other sources did not find these effects [2, 3, 4, 5]. In the Cochrane review, the relative risk (RR) of complications was 0.95 (95% CI 0.70 to 1.29), of emergency department visits 0.72 (95% CI 0.39 to 1.32) and of readmissions 1.20 (95% CI 0.54 to 2.65) [2, 3]. Each estimate was based on 3 studies with 250 participants and rated low certainty [2, 3]. Length of hospital stay could not be pooled, and the included trials did not report a difference between groups [2, 3]. The geriatric meta-analysis found no statistically significant difference in length of stay, postoperative complications or quality of life [5]. The 2024 trial graded complications with the Clavien-Dindo classification and found no statistically significant difference in complications or length of stay [4].

The two meta-analyses that address older patients therefore point in opposite directions [1, 5]. One reports benefit particularly in older populations; the one limited to elderly patients found no significant effect on complications or stay [1, 5]. The 14-article meta-analysis is the only source whose abstract explicitly lists retrospective studies among its included designs, and it is also the largest, with 2314 patients [1, 2, 3, 5]. The abstracts do not allow design mix to be confirmed as the explanation, because the geriatric meta-analysis also included cohort studies and found no difference in subgroup analyses by study design or by control group [5]. Neither meta-analysis abstract lists its included trials, so it is not possible to tell from them how much the two overlap or which studies drive the positive estimate [1, 5].

## One dataset, two readings

The 2022 and 2023 Cochrane records report identical complication, emergency department and readmission estimates but interpret them differently [2, 3]. The 2022 version states that prehabilitation may result in fewer complications and fewer emergency department visits, and may result in a higher readmission rate [3]. The 2023 version describes the same effects as small or even trivial and concludes that a solid effect on complications, emergency department visits and readmissions could not be established [2]. Because each confidence interval spans values favouring both groups and certainty is low, the 2023 wording is the more conservative reading of the same numbers [2, 3]. Both versions caution that only three heterogeneous studies were included and that the findings should be interpreted with caution [2, 3].

## What remains unknown

Several questions cannot be answered from these sources [1, 2, 3, 4, 5].

- Clear definitions of the modality, content and duration of prehabilitation, including its nutrition, exercise and psychological components, are lacking [1].
- The Cochrane review could not analyse VO2peak, handgrip strength, mortality, health-related quality of life, return to normal activities, programme safety or compliance because of missing or insufficient data [2, 3].
- Whether walk-test differences translate into fewer complications is unresolved, since the sources that reported walk-test differences did not report complication differences [2, 3, 4, 5].
- The 2024 trial listed implementation and indirect costs among its secondary aims, but the interim abstract does not report cost results [4].
- The Cochrane search ended in January 2021, and its authors noted numerous ongoing RCTs intended for a future update [2, 3].
- Generalisability is limited: the Cochrane trials were conducted in tertiary centres in patients with non-metastatic disease undergoing mainly laparoscopic surgery [2, 3]. The 2024 trial excluded, among others, patients with metastatic disease, severe walking impairment or preoperative chemoradiation [4].

## Reading the evidence in practice

The most consistent signal across sources is a walk-test difference favouring prehabilitation, but its strength varies [2, 3, 4, 5]. The Cochrane review rated its preoperative estimate as moderate certainty and its postoperative estimates as low or very low certainty [2, 3]. The geriatric meta-analysis reported a significant difference without specifying timing, and the interim trial reported larger differences in a small sample [4, 5]. Evidence on complications and hospital stay is divided: one mixed-design meta-analysis reported benefit, while the RCT-based Cochrane review, the geriatric meta-analysis and the interim trial reported no clear difference [1, 2, 3, 4, 5]. The authors of the geriatric meta-analysis judged the clinical use of multimodal prehabilitation within ERAS to be limited for elderly patients, while noting potential for targeted and optimised interventions in selected populations [5].

AthleticsMD, founded by a critical care anesthesiologist and a general surgeon, offers PREOOP surgical pre-optimization programs in Columbia and Laurel/Fort Meade, Maryland [F]. Because the trials enrolled selected patients and effects on complications remain uncertain, whether prehabilitation fits an individual surgical plan is a question to talk through with a clinician [F, 2, 3, 4].

## Limitations

This review is based on published abstracts, which omit the lists of included trials, subgroup estimates and risk-of-bias detail that the full texts may contain [1, 2, 3, 4, 5]. The 2022 and 2023 Cochrane records describe one review of the same three trials, so they are not independent confirmation of each other [2, 3]. Because neither meta-analysis abstract lists its included studies, the extent of overlap between them, and therefore how independent their results are, cannot be judged [1, 5]. The 14-article meta-analysis pooled retrospective studies and the geriatric meta-analysis pooled cohort studies alongside RCTs, so parts of both rest on observational comparisons [1, 5]. The 2024 trial is a single-centre interim analysis of 71 patients, and its final results may differ [4]. Definitions of older patients also vary: the geriatric meta-analysis covered ages 65 to 82, and the abstract of the other meta-analysis does not state an age threshold [1, 5].

## References

1. Liao YS, Chiu HY, Huang FH, et al. Prehabilitation Interventions in Patients Undergoing Colorectal Cancer Surgery: A Systematic Review and Meta-Analysis. J Am Geriatr Soc. 2025;73(7):2262-2277. doi:10.1111/jgs.19425. PMID: 40079672. https://pubmed.ncbi.nlm.nih.gov/40079672/
2. Molenaar CJ, van Rooijen SJ, Fokkenrood HJ, Roumen RM, Janssen L, Slooter GD. Prehabilitation versus no prehabilitation to improve functional capacity, reduce postoperative complications and improve quality of life in colorectal cancer surgery. Cochrane Database Syst Rev. 2023;5(5):CD013259. doi:10.1002/14651858.CD013259.pub3. PMID: 37162250. https://pubmed.ncbi.nlm.nih.gov/37162250/
3. Molenaar CJ, van Rooijen SJ, Fokkenrood HJ, Roumen RM, Janssen L, Slooter GD. Prehabilitation versus no prehabilitation to improve functional capacity, reduce postoperative complications and improve quality of life in colorectal cancer surgery. Cochrane Database Syst Rev. 2022;5(5):CD013259. doi:10.1002/14651858.CD013259.pub2. PMID: 35588252. https://pubmed.ncbi.nlm.nih.gov/35588252/
4. Pesce A, Fabbri N, Colombari S, et al. A randomized controlled clinical trial on multimodal prehabilitation in colorectal cancer patients to improve functional capacity: preliminary results. Surg Endosc. 2024;38(12):7440-7450. doi:10.1007/s00464-024-11198-8. PMID: 39210058. https://pubmed.ncbi.nlm.nih.gov/39210058/
5. Srinivasan A, Yi KM, Sharma D, Mantoo SK. Integrating multimodal prehabilitation into enhanced recovery after surgery programs (MPhERAS) for elderly patients: a systematic review and meta-analysis of randomized controlled trials and cohort studies. Tech Coloproctol. 2025;30(1):28. doi:10.1007/s10151-025-03259-4. PMID: 41455772. https://pubmed.ncbi.nlm.nih.gov/41455772/