Functional and postoperative outcomes after preoperative exercise training in patients with lung cancer: a systematic review and meta-analysis

Lung cancer is the leading cause of cancer-related death worldwide. For early stages of the disease, lung resection surgery remains the best treatment with curative intent, but significant morbidity is associated, especially among patients with poor pulmonary function and cardiorespiratory fitness. In those cases, the implementation of a preoperative exercise-based intervention could optimize patient's functional status before surgery and improve postoperative outcomes and enhance recovery. The aim of this systematic review is to provide the current body of knowledge regarding the effectiveness of a preoperative exercise-based intervention on postoperative and functional outcomes in patients with lung cancer submitted to lung resection surgery. A systematic review of the literature using CINAHL, EMBASE, MEDLINE, Pubmed, PEDro and SCOPUS was undertaken in September 2015 yielding a total of 1656 references. Two independent reviewers performed the assessment of the potentially eligible records against the inclusion criteria and finally, 21 articles were included in the review. Articles were included if they examined the effects of an exercise-based intervention on at least one of the selected outcomes: pulmonary function, (functional) exercise capacity, health-related quality of life (HRQoL) and postoperative outcomes (length of stay and postoperative complications). Fourteen studies were further selected for a meta-analysis to quantify the mean effect of the intervention and generate 95% confidence intervals (CIs) using the Cochrane Review Manager 5.0.25. For two of the outcomes included (exercise capacity and HRQoL), studies showed large heterogeneity and thus, a meta-analysis was considered inappropriate. Pulmonary function (forced vital capacity and forced expiratory volume in 1 s) was significantly enhanced after the intervention [standardized mean difference (SMD) = 0.38; 95% CI 0.14, 0.63 and SMD = 0.27, 95% CI 0.11, 0.42, respectively]. In comparison with the patients in the control groups, patients in the experimental groups spent less days in the hospital (mean difference = -4.83, 95% CI -5.9, -3.76) and had a significantly reduced risk for developing postoperative complications (risk ratios = 0.45; 95% CI 0.28, 0.74). In conclusion, preoperative exercise-based training improves pulmonary function before surgery and reduces in-hospital length of stay and postoperative complications after lung resection surgery for lung cancer.