Lee, J.W., Lee, W.B., Kim, W., Min, B.I., Lee, H., & Cho, S.H. (2015). Traditional herbal medicine for cancer pain: A systematic review and meta-analysis. Complementary Therapies in Medicine, 23, 265–274. 

STUDY PURPOSE: To evaluate the effects of herbal medicine as adjunctive treatment for cancer-related pain

• FINAL NUMBER STUDIES INCLUDED = 24 (four included in the meta-analysis)
• TOTAL PATIENTS INCLUDED IN REVIEW = 4,045
• AVERAGE SAMPLE SIZE: 70 patients (One Chinese study included 2,466 patients.)
• KEY SAMPLE CHARACTERISTICS: Various tumor types

The results of this meta-analysis showed an overall standard mean difference in favor of the herbal intervention across four studies (SMD = -0.51, p < 0.05). In a second meta-analysis, the risk ratio reported was 1.6. The direction of this risk ratio was not clear in the results reported. A meta-analysis was done for studies using herbal interventions in combination with traditional cancer therapy versus only traditional cancer therapy rather than treatment aimed specifically at pain control. Types of in interventions included botanicals, processed animal products, and processed minerals. In some studies, herbal interventions were compared to chemotherapy, aspirin, NSAIDs, Tylenol, diets, placebos, or unnamed analgesic drugs. Most studies showed a high risk of bias according to a study evaluation. A single study that was of high quality across all aspects showed no effect for the intervention.

Although the quantitative analysis showed a statistic significance, the comparisons studied for pain relief did not appear to be appropriate. Although herbal medicine may have better results on pain than no intervention or low-level analgesics, the efficacy of herbal medicine for pain should compare results with those obtained from other interventions shown to be effective for cancer-related pain.

Most studies were of low quality. Many study comparison groups were not adequate because well-recognized, effective interventions for pain were not used in the controls. The results reported in the meta-analysis of risk ratios were unclear. The methods described the use of an odds ratio analysis, but a risk ratio was reported, and it was not clear which study group was considered at-risk.

The findings of this analysis suggested that traditional herbal medicine may have a role in cancer-related pain control. However, the included studies did not provide strong evidence. The potential effects of herbal medicine for pain management remain unclear. Additional well-designed research, including comparisons to pain interventions with strong supportive evidence, are needed to determine any benefits of herbal medicine.