Trends in the use of Japanese herbal Kampo medicine in inpatients with cancer: a 14-year nationwide analysis.

Background: Kampo medicine (Japanese herbal medicine) is often used to manage the side effects of cancer treatment and improve quality of life. However, nationwide trends in Kampo use among inpatients with cancer in Japan remain poorly understood. This study aimed to examine the temporal trends and clinical practice patterns of Kampo prescriptions among inpatients with cancer between 2010 and 2023, with a focus on their use in acute or severe conditions.

Methods: This retrospective cohort study used the Japanese Diagnosis Procedure Combination database, including over 6.8 million hospitalizations for five major cancer types (breast, colorectal, gastric, lung, and prostate)between July 2010 and March 2023. Kampo use was identified from in-hospital prescription data. Prescription trends and patient characteristics were analyzed.

Results: Kampo medicines were prescribed in 13.6% of hospitalizations, more commonly among older adults and patients with colorectal cancer. The overall prescription proportion increased from 2010 to 2017 before plateauing. The top five prescribed Kampo medicines were Dai-ken-chu-to, Gosha-jinki-gan, Rikkunshi-to, Shakuyaku-kanzo-to, and Hange-shashin-to. Prescription patterns varied by age group, cancer type, cancer stage, disease status, and cause of hospitalization. Dai-ken-chu-to use shifted from postoperative to chronic care, while Gosha-jinki-gan prescriptions gradually declined.

Conclusions: Kampo prescription patterns among inpatients with cancer have changed over the past fourteen years, reflecting changes in patient demographics and treatment strategies. Kampo medicines appear to be selectively used as supportive care tailored to specific clinical situations. These findings highlight the evolving role of traditional medicine in modern cancer care in Japan.