Exercise prehabilitation may lead to augmented tumor regression following neoadjuvant chemoradiotherapy in locally advanced rectal cancer.

We evaluate the effect of an exercised prehabilitation programme on tumour response in rectal cancer patients following neoadjuvant chemoradiotherapy (NACRT). Rectal cancer patients with (MRI-defined) threatened resection margins who completed standardized NACRT were prospectively studied in a post hoc, explorative analysis of two previously reported clinical trials. MRI was performed at Weeks 9 and 14 post-NACRT, with surgery at Week 15. Patients undertook a 6-week preoperative exercise-training programme. Oxygen uptake (VO2) at anaerobic threshold (AT) wasmeasured at baseline (pre-NACRT), after completion of NACRT and at week 6 (post-NACRT). Tumour related outcome variables: MRI tumour regression grading (ymrTRG) at Week 9 and 14; histopathological T-stage (ypT); and tumour regression grading (ypTRG)) were compared. 35 patients (26 males) were recruited. 26 patients undertook tailored exercise-training with 9 unmatched controls. NACRT resulted in a fall in VO2 at AT -2.0 ml/kg/min(-1.3,-2.6),  < 0.001. Exercise was shown to reverse this effect. VO2 at AT increased between groups, (post-NACRT vs. week 6) by +1.9 ml/kg/min(0.6, 3.2),  = 0.007. A significantly greater ypTRG in the exercise group at the time of surgery was found ( = 0.02). Following completion of NACRT, exercise resulted in significant improvements in fitness and augmented pathological tumour regression.