Looby M; Academic Surgery, Cancer Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.; Southampton Complex Cancer and Exenteration Team (SCCET), University Hospital Southampton, Southampton, UK.
Matthews L; West CT; Khan K; Ansell G;Donovan K; Wood L;  Tapley P; Lewis R; Stoddard K; Grocott MPW; Jack S; Yano H; Levett D;Mirnezami A; West MA;

Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland [Colorectal Dis] 2025 Nov; Vol. 27 (11), pp. e70298.

Aim: Locally advanced pelvic malignancies, such as colorectal and anal cancers, can only be cured through multimodal cancer treatment including multi-visceral exenterative resections, which carry a high mortality and morbidity risk. Despite strong predictive abilities in other cancer cohorts, the combined prognostic value of body composition and cardiopulmonary exercise testing (CPET) for major in-hospital morbidity in patients undergoing exenterative surgery for advanced pelvic cancers has not been evaluated.
Method: A locally advanced colorectal and anal cancer cohort was derived from a prospectively maintained quaternary database. CPET was undertaken preoperatively, according to national guidelines. Skeletal muscle index (SMI) and radiation attenuation (SM-RA) were obtained from analysing L3 slices from preoperative computed tomography scans using SliceOmatic 5.0 and classified using predefined thresholds. Major morbidity was defined as Clavien-Dindo classification 3a or greater.
Results: From 247 patients (58% male, median age 60 years), 62.4% and 35.5% had locally advanced or recurrent disease respectively. Physical fitness variables were significantly reduced in low SMI or low SM-RA patients. In multivariate linear regression, SMI was strongly predictive of oxygen uptake at the anaerobic threshold (B = 0.013, p = 0.001) and at peak (B = 0.015, p = 0.002). 17.3% of all patients experienced a major postoperative complication. In multivariate analysis, reduced peak power output (<1.5 W kg ^-1 ) was significantly associated with an increased risk of postoperative major morbidity (OR = 2.6, p = 0.012).
Conclusion: CPET may be predictive of in-hospital major morbidity in this cohort. The association of CPET with body composition necessitates further evaluation and external validation in a larger patient cohort, specifically interrogating their combined role in morbidity prediction and as a target for prehabilitation interventions.