Background: Pain and numbness in cancer survivors frequently have negative impacts on quality of life (QoL). This meta-analysis aimed to identify the current treatment options for pain and numbness in cancer survivors and to evaluate their effects.
Methods: Cancer survivors were defined as patients diagnosed with cancer who had completed active cancer treatment, whose conditions were stable, and who had no evidence of recurrent or progressive disease. A systematic search through the PubMed, MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Web of Science, PsycInfo, and CINAHL databases was conducted, which targeted randomized controlled trials (RCTs) published until April 2022 that evaluated any type of treatment for pain or numbness in cancer survivors. A meta-analysis was conducted using the random-effects model to obtain the effect sizes of 7 types of treatments: opioid therapy, nonopioid pharmacotherapy, interventional therapy, acupuncture, education/cognitive behavioral therapy (CBT), physical exercise, and alternative medicine.
Results: A total of 36 studies involving 2,870 cancer survivors were included. Among them, 35 (n=2,813) were included in the meta-analysis for pain. The analysis suggested that physical exercise [n=761; 13 studies; standardized mean difference (SMD) -0.84; 95% confidence interval (CI): -1.14 to -0.55], acupuncture (n=409; 3 studies; SMD -0.80; 95% CI: -1.04 to -0.56), and alternative medicine (n=206; 6 studies; SMD -0.44; 95% CI: -0.71 to -0.16) could significantly reduce pain. Nonopioid pharmacotherapy and education/CBT did not demonstrate significant effects. No studies were identified that investigated the effects of opioid therapy or interventional therapy on pain. Regarding numbness, 5 studies (n=566) were included in the meta-analysis. Acupuncture (n=99; 2 studies) did not demonstrate significant effects on numbness, and the effects of nonopioid pharmacotherapy, education/CBT, and physical exercise could not be determined due to the small number of included studies. No studies were identified that investigated the effects of opioid therapy, interventional therapy, or alternative medicine on numbness.
Conclusions: This meta-analysis suggested that physical exercise, acupuncture, and alternative medicine may reduce pain in cancer survivors, with a very small to moderate amount of evidence. The effect of treatments for numbness could not be determined due to the limited number of included studies. Further studies are needed, particularly on widely used pharmacotherapy.
Keywords: Meta-analysis; cancer survivors; numbness; pain; treatment.