Efficacy of Japanese traditional (Kampo) medicine for treating chemotherapy-induced peripheral neuropathy: A retrospective case series study

AIM: To investigate Japanese traditional (Kampo) medicine’s effectiveness on cancer chemotherapy-induced peripheral neuropathy (CIPN), we carried out this retrospective study. METHODS: By searching our outpatient database of 3154 patients who consulted our outpatient clinic of Japanese-Oriental (Kampo) Medicine at Chiba University Hospital from November 2005 to December 2010, a total of 281 patients diagnosed with cancer were identified. Twenty-four patients out of the 281 patients identified met the following three conditions and were eligible for further investigation of the effectiveness of Kampo treatment: At least one course of cancer chemotherapy had been administered; numbness and pain appeared after the chemotherapy; and CIPN was diagnosed before they were given Kampo treatment. RESULTS: The 24 patients included 6 males and 18 females and ranged in age from 39 to 86 (mean 61.2 ± 11.5) years old. Kampo formulas were individually chosen by Kampo expert doctors based on Kampo-specific diagnostics. Beneficial outcomes were obtained by Kampo treatment in 20 out of the 24 cases (83.3%). Nine out 20 cases had a major response (the numbness and pain showed improvement or reduction by 50% or more), with 7 of 9 cases showing a more than 70% symptom reduction. Eleven out of 20 cases showed a minor response (less than 50% symptom reduction), and 4 out of the 24 cases had no beneficial response. The most frequently used formula was goshajinkigan (GJG), followed by hachimijiogan (HJG) and keishibukuryogan. Thirteen of the 24 cases (54.2%) were prescribed aconite root-containing formulas including GJG and HJG. Aconite root has “warming” effects and ameliorates pain and numbness; 21 out of 24 cases (87.5%) in total used warming formulas such as aconite root-containing formulas to reduce CIPN. CONCLUSION: Our current study suggested that Kampo formulas chosen based on Kampo-specific diagnostics could be for treating CIPN that is refractory to conventional medicine.