Clinical Evidence for the Effects of Manual Therapy on Cancer Pain: A Systematic Review and Meta-Analysis

OBJECTIVE: This meta-analysis aimed to evaluate the effects of manual therapy (MT) on cancer pain, so as to provide clinical evidence for application. METHODS: Five English and Chinese databases were searched until February 29, 2020, for randomized controlled trials (RCTs) of MT for cancer pain. Articles published in the English or Chinese language were included. Two authors independently reviewed all articles and extracted the data, and any disagreements in the above process were discussed with other reviewers until the authors reached consensus. Review Manager 5.3 was used to calculate the effect size and 95% confidence intervals. This review was registered in PROSPERO, number CRD42020172053. RESULTS: The intensity of cancer pain is our primary outcome measure, and compared with standard care, MT can significantly relieve the pain of patients with cancer (SMD, 0.63; 95% CI [0.18, 1.08]; P=0.006 < 0.01); the effects of MT plus active activity were significantly different from AT alone (SMD, 0.79; 95% CI [0.28, 1.30]; P=0.002 < 0.01); there was no statistical difference in the efficacy of MT and AT alone (SMD, -0.24; 95% CI [-1.09, 0.62]; P=0.53 > 0.05). In other related symptoms, the above evidence cannot support that MT had a good effect on fatigue (SMD, 0.77; 95% CI [-0.09, 1.63]; P=0.08 > 0.05), nausea (SMD, 0.24; 95% CI [-0.00, 0.48]; P=0.05), anxiety (SMD, 0.76; 95 % CI [-0.32, 1.84]; P=0.17 > 0.05), and depression (SMD, 0.67; 95 % CI [-0.28, 1.62]; P=0.17 > 0.05); however, MT intervention can improve physical function (n = 271; SMD, 0.35; 95 % CI [-0.04, 0.74]; P=0.04 < 0.05) and global well-being (SMD, 0.50; 95 % CI [0.02, 0.98]; P=0.04 < 0.05). In addition, MT had a significant effect on pain relief (SMD, 0.52; 95% CI [0.03, 1.01]; P=0.04 < 0.05) and improvement of physical function (SMD, 0.28; 95% CI [0.02, 0.53]; P=0.03 < 0.05) even after a period of time after treatment. CONCLUSION: MT was an effective intervention, which may have immediate effect on cancer pain and may improve physical function and global well-being. In the view of follow-up effects, MT had good effects for the reduction of pain and the recovery of physical function. However, because of limitations, the seemingly promising results should be interpreted with caution.