Trends in Kampo Medicine Usage as Supportive Care During Anticancer Drug Treatment in Japanese Patients: A Nationwide Cohort Analysis from Fiscal Years 2015 to 2021

The adverse effects of anticancer drugs significantly impact the quality of life of patients undergoing chemotherapy, necessitating evidence-based supportive therapies. In Japan, Kampo medicines, traditional Japanese herbal therapies used for relief of various symptoms, have been widely used as complementary and alternative treatments for cancer, despite limited evidence regarding their efficacy and safety. Thus, we investigated the actual use of Kampo medicines as supportive care in patients undergoing anticancer drug treatment and evaluated the trends in prescription according to year. We analyzed 89,141 cancer drug therapy cases registered in the Japan Medical Data Center database between April 2014 and July 2022, excluding those with a history of Kampo medicine prescriptions before the first prescription of antineoplastic drugs. We assessed the trends in prescription according to sex, age group (<50, 50-74, and ≥75 years), and cancer type subgroup using the Cochran-Armitage trend test. Approximately 23.7% of patients were prescribed Kampo medicines during anticancer drug treatment. Since 2014, a decrease in the prescription of Kampo medicines during anticancer treatment has been observed regardless of sex, age, or cancer type. These findings suggest that recent negative reports on the efficacy and safety of Kampo medicines in cancer care may have influenced this trend.