Effects of Chinese herbal medicine on colorectal adenoma recurrence following polypectomy: A systematic review and meta-analysis

Yi Cheng ^1,2 Yuan Ming Di ¹ Brian May ¹ Anthony Lin Zhang ¹ Charlie Changli Xue ^1,2* Beiping Zhang ^2,3*

• ¹ RMIT University, Melbourne, Australia
• ² Guangdong Provincial Hospital of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong Province, China
• ³ State Key Laboratory of Dampness Syndrome of Chinese Medicine, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong Province, China

Objective: Preventing colorectal adenoma (CRA) recurrence after polypectomy is essential. However, the current evidence of Chinese herbal medicine (CHM) for CRA recurrence is still limited. This study aims to synthesize the effects of CHM as a prevention method for CRA recurrence.Methods: Nine databases were searched up to May 2024. Randomised controlled trials identifying the preventive effects of CHM among people with CRA post-polypectomy were included. Excel forms were used to collect and extract data. RevMan and STATA were used for data analysis. We performed subgroup and sensitivity analyses to explore the influencing variables.Results: Twenty trials (2,325 participants) were included. The commonly used botanical drugs consisted of strengthening the spleen and anti-tumour metabolites. Compared to routine care (RC) alone, oral CHM plus RC significantly reduced the CRA recurrence rate at 12 months (RR 0.51, 95% CI [0.39, 0.67], I2 = 42%), 6 months (RR 0.44, 95% CI [0.36, 0.55], I2 = 0%) and 3 months (RR 0.46, 95% CI [0.22, 0.96], I2 = 0%) post-polypectomy. Compared to CHM placebo plus RC, San zi granule combined with RC was better at reducing CRA recurrence at 12 months post-polypectomy (RR 0.39, 95% CI [0.16, 0.93], I2 = 0%), and during 2-year follow-up (RR 0.73, 95% CI [0.58, 0.90]). There was no significant difference between groups for treatment duration and syndromes. Additional analysis showed that , oral CHM containing the botanical drugs of Si jun zi decoction plus RC was better at reducing CRA recurrence at 12 months post-polypectomy with a low heterogeneity, compared to RC alone (RR 0.26, 95% CI [0.13, 0.54], I2 = 0%). Adverse events were similar in the above two comparisons.Conclusions: Oral CHM combined with RC may reduce CRA recurrence and be well tolerated. San zi granule and Si jun zi decoction may be the representative prescriptions. Experimental studies of the frequent botanical drugs have found anti-cancer effects that may account for the clinical findings. Future rigorous clinical trials are needed due to low-to-moderate certainty of evidence.