Beg MA; The Royal Marsden Hospital, NHS Foundation Trust, London, UK.
Frountzas M; Oliver A; Plete NK; Akhbari AR;et al

Surgery. 196:110283, 2026 Aug.

BACKGROUND: Locally advanced rectal cancers may require beyond total
mesorectal excision, including extensive procedures, such as total pelvic
exenteration. These operations carry significant morbidity.
Cardiopulmonary exercise testing is utilized to assess physiological
fitness before major surgery. However, limited evidence exists regarding
its predictive value in beyond total mesorectal excision. This study aimed
to determine whether preoperative cardiopulmonary exercise testing
parameters are associated with postoperative morbidity following beyond
total mesorectal excision, with subgroup analysis of patients undergoing
total pelvic exenteration.

METHODS: A retrospective cohort study was conducted at a tertiary center,
including consecutive patients who underwent cardiopulmonary exercise
testing prior to beyond total mesorectal excision between 2014 and 2021.
Associations between anaerobic threshold (AT VO2) and peak oxygen
consumption (VO2 peak) with major perioperative morbidity (Clavien-Dindo
>=3) were investigated. Receiver operating characteristic analysis
identified optimal cutoff values, which were used to dichotomize patients
into low- and high-risk groups. Groups were compared using chi2 and
Mann-Whitney U tests.

RESULTS: A total of 116 patients were included, of whom 62 underwent
total pelvic exenteration. In the overall beyond total mesorectal excision
cohort, cardiopulmonary exercise testing parameters could not demonstrate
any significant correlation with postoperative outcomes. However, in the
total pelvic exenteration subgroup, both AT VO2 (area under the curve
0.68; P = .035) and VO2 peak (area under the curve 0.73; P = .013) were
associated with significant morbidity. Receiver operating
characteristic-derived thresholds (AT VO2 <11.45 mL/kg/min; VO2 peak
<19.15 mL/kg/min) identified higher complication rates (30-31% vs 6-7%)
and longer hospital stay.

CONCLUSION: Cardiopulmonary exercise testing seems to present an
exploratory association with perioperative morbidity in patients
undergoing total pelvic exenteration but did not show any significant
association across the broader beyond total mesorectal excision cohort.
Incorporating cardiopulmonary exercise testing into preoperative
assessment may support risk stratification and targeted optimization
before complex rectal cancer surgery.