An Overview of Systematic Reviews and Meta-Analyses of Clinical Studies of Acupuncture for Cancer Pain.

Background: Systematic reviews (SRs) and meta-analyses (MAs) for the use of acupuncture for cancer pain have been increasing, but the evidence has not been systematically and comprehensively assessed. We aimed to perform an overview of the evidence quality of SRs/MAs of acupuncture for improving cancer pain.

Methods: 8 databases were systematically searched to identify SRs/MAs of acupuncture for improving cancer pain. The A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR-2), Risk of Bias in Systematic Reviews (ROBIS), Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), and Grades of Recommendations, Assessment, Development, and Evaluation (GRADE), respectively, were applied by 2 independent reviewers to evaluate the methodological quality, risk of bias, reporting quality, and evidence quality.

Results: A total of 14 SRs/MAs were included in the present study. By AMSTAR-2, two reviews were rated as having high methodological quality, while 12 were given a critically low rating. All SRs/MAs in Phase 1, Domain 1, and Domain 4, according to ROBIS, were at low risk. Furthermore, 4 reviews in Domain 2, twelve reviews in Domain 3, and ten SRs/MAs in Phase 3, were rated as having low risk of bias. With reporting quality, some reporting flaws were identified in the topic of protocol and registration, additional analyses, and search strategy. According to GRADE, the level of evidence quality was "critically low" to "moderate," and risk of bias was the most common downgraded factor.

Conclusion: Acupuncture may be beneficial in improving cancer pain. However, due to the identified limitations and inconsistent findings, we recommend further rigorous, and more standardized SRs/MAs to provide strong evidence for definitive conclusions.