Cancer survivor inspiratory muscle training: systematic review and Bayesian meta-analysis

BACKGROUND: The long-term impact of cancer treatment is associated with respiratory dysfunction and physical fitness impairment. Although inspiratory muscle training (IMT) has been shown as an effective exercise therapy in cancer survivors, there is no evidence on the optimal dose, application moment nor specific population effects of this intervention. The main objective of this meta-analysis is to analyse the effects of IMT on pulmonary function, physical fitness and quality of life (QoL) in cancer survivors. METHODS: This systematic review and meta-analysis was preregistered in the International Prospective Register of Systematic Reviews (PROSPERO) register and conducted according to the Preferred Reporting for Systematic Reviews and Meta-analysis statement. We used a Bayesian multilevel random-effects meta-analysis model to pool the data. Multilevel metaregression models were used to examine the conditional effects of our covariates. Convergence and model fit were evaluated through specific model parameters. Sensitivity analyses removing influential cases and using a frequentist approach were carried out. RESULTS: Pooled data showed that IMT intervention is effective to improve pulmonary function (standardised mean difference=0.53, 95% credible interval 0.13 to 0.94, SE=0.19). However, IMT did not present statistically significant results on physical fitness and QoL. Metaregression analyses found that the type of cancer, the moment of application and the evaluation tool used had significant moderation effects on pulmonary function. CONCLUSION: IMT could be an important part in the management of side effects suffered by cancer survivors. Considering the current evidence, this intervention is highly recommended in patients diagnosed with oesophageal and lung cancers. IMT may provide superior benefits before the biological treatment and after the surgery. PROSPERO REGISTRATION NUMBER: 304909.