Database	Time span	Search strategy
The Central Register of Controlled Trials (CENTRAL) in the Cochrane Library	Issue 8, 2016	#1 MeSH descriptor: [Carcinoma, Hepatocellular] explode all trees #2 (((hepat* or liver) and carcinoma*) or hepatocellular carcinoma or hepatocarcinoma or hepatoma or HCC or "primary liver cancer") #3 #1 or #2 #4 (early or small) #5 #3 and #4
MEDLINE (OvidSP)	January 1947 to September 2016	1. exp Carcinoma, Hepatocellular/ 2. (((hepat* or liver) and carcinoma*) or hepatocellular carcinoma or hepatocarcinoma or hepatoma or HCC or "primary liver cancer").ti,ab. 3. 1 or 2 4. (early or small).ti,ab. 5. 3 and 4 6. randomized controlled trial.pt. 7. controlled clinical trial.pt. 8. randomized.ab. 9. placebo.ab. 10. drug therapy.fs. 11. randomly.ab. 12. trial.ab. 13. groups.ab. 14. 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 15. exp animals/ not humans.sh. 16. 14 not 15 17. 5 and 16
Embase (OvidSP)	January 1974 to September 2016	1. exp liver cell carcinoma/ 2. (((hepat* or liver) and carcinoma*) or hepatocellular carcinoma or hepatocarcinoma or hepatoma or HCC or "primary liver cancer").ti,ab. 3. 1 or 2 4. (early or small).ti,ab. 5. 3 and 4 6. exp crossover‐procedure/ or exp double‐blind procedure/ or exp randomized controlled trial/ or single‐blind procedure/ 7. (((((random* or factorial* or crossover* or cross over* or cross‐over* or placebo* or double*) adj blind*) or single*) adj blind*) or assign* or allocat* or volunteer*).af. 8. 6 or 7 9. 5 and 8
Science Citation Index Expanded (Web of Knowledge)	January 1945 to September 2016	#1 TS=(((hepat* or liver) and carcinoma*) or hepatocellular carcinoma or hepatocarcinoma or hepatoma or HCC or "primary liver cancer") #2 TS=(early or small) #3 TS=(random* OR rct* OR crossover OR masked OR blind* OR placebo* OR meta‐analysis OR systematic review* OR meta‐analys*) #4 #1 AND #2 AND #3
World Health Organization International Clinical Trials Registry Platform Search Portal (apps.who.int/trialsearch/Default.aspx)	September 2016	Title: (early or small) Condition: "hepatocellular carcinoma" or "primary liver cancer" or "liver cell cancer" or hepatoma
ClinicalTrials.gov	September 2016	early OR small | Interventional Studies | "hepatocellular carcinoma" OR "primary liver cancer" OR "liver cell cancer" OR hepatoma | Phase 2, 3, 4