To explore the effects of herbal medicine among cancer patients in Taiwan: A cohort study.

Background: Traditional Chinese medicine (TCM) is widely used by ethnic Chinese communities. TCM is covered by Taiwan's National Health Insurance (NHI) program. We evaluated the efficacy and outcomes of complementary Chinese herbal medicine (CHM) therapy in patients with cancer.

Methods: This population-based cohort study was conducted using the data of patients who received a cancer diagnosis between 2005 and 2015 in Taiwan. Eligible patients were divided into standard and complementary CHM therapy groups. The complementary CHM therapy group was further divided into low cumulative dosage (LCD), medium cumulative dosage (MCD), and high cumulative dosage (HCD) subgroups. Overall survival (OS), mortality risk, cancer recurrence, and metastasis were analyzed for all cancers and five major cancers (lung, liver, breast, colorectal, and oral cancers).

Results: We included 5707 patients with cancer (standard therapy, 4797 [84.1%]; complementary CHM therapy, 910 [15.9%]; LCD, 449 [7.9%]; MCD, 374 [6.6%], and HCD, 87 [1.5%]). For the LCD, MCD, and HCD subgroups, the mortality risk was 0.83, 0.64, and 0.45, and the 11-year OS, 5-year cumulative cancer recurrence, and 5-year cumulative cancer metastasis rates were 6.1 ± 0.2, 6.9 ± 0.2, and 8.2 ± 0.4 years; 39.2%, 31.5%, and 18.8%; and 39.5%, 32.8%, and 16.6%, respectively. The cumulative cancer recurrence and metastasis rates of the standard therapy group were 40.9% and 32.8%, respectively. The cumulative recurrence and metastasis rates of all cancers, lung cancer, and liver cancer and all cancers, colorectal cancer, and breast cancer, respectively, were significantly lower in the HCD subgroup than in the other subgroups and standard therapy group ( p < 0.05).

Conclusion: Patients receiving complementary CHM therapy may have prolonged OS and reduced risks of mortality, recurrence, and metastasis. A dose-response relationship was noted between CHM therapy and mortality risk: increased dosage was associated with improved OS and reduced mortality risk.