Preoperative high intensity interval training for oncological resections: A systematic review and meta-analysis

Exercise prehabilitation prior to major surgery targets a reduction in postoperative complications through improved conditioning and respiratory function. However its effectiveness in cancer surgery is unclear. The objective of this review was to determine if preoperative high-intensity interval training (HIIT) improves preoperative fitness in patients scheduled for oncologic resection, and whether postoperative complications are impacted. METHODS: CINAHL, AMED, PEDro, EMBASE, The Cochrane Library and PubMed/MEDLINE were searched until April 2021 using predefined search strategy and accompanied by manual forward and backwards citation review. Screening of titles, abstracts, full-texts, data extraction, risk of bias assessment and methodologic quality was performed independently by two reviewers. Mean difference (MD) with 95% confidence intervals (CI) was compared and heterogeneity assessed using Chi Squared Test and I² statistic. Six randomised controlled trials (RCTs) were included in the systematic review. Interventions prescribed bouts of high-intensity exercise [80-115% peak work rate (WRp)] interspaced with low-intensity (rest-50% WRp) exercise. The meta-analysis included five RCTs reporting peak oxygen consumption (VO_2peak). Preoperative HIIT did not result in significantly higher VO_2peak in comparison to usual care or moderate intensity exercise (MD 0.83, 95%CI-0.51-2.17) kg/ml/min, p = 0.12). Studies were insufficiently powered with respect to postoperative complications, but there is no evidence of significant impact. No adverse events occurred and high adherence rates were reported. Results of this systematic review and meta-analysis demonstrate there is insufficient evidence to support HIIT as a method of improving preoperative fitness prior to oncologic resection. Further work is needed to determine if specific HIIT parameters can be adapted to improve efficacy over short time-frames.