Matsumoto 2002.

Methods	Randomised controlled trial.
Participants	72 patients with T2/T3 primary colon or rectal tumours undergoing curative resection. 8 were excluded which were "equally distributed between the treatment groups" (three did not undergo curative resection, three did not have adequate drug delivery, three patients had inappropriate stage). Hence, N=64.
Interventions	Patient randomised to : ‐ Control: 8mg/m2 of mitomycin with 24 hours following the operation + 200mg of daily oral 5‐fluorouracil from two weeks till 1 year. ‐ Intervention: 800mg of daily oral cimetidine from two weeks post‐operatively to 1 year + 8mg/m2 of mitomycin with 24 hours following the operation + 200mg of daily oral 5‐fluorouracil from two weeks till 1 year.
Outcomes	Overall survival
Notes	In an interim report the aim of the study was stated as to assess if cimetidine could "reduce appetite loss and reflux oesophagitis in colorectal cancer patients".
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Patients 'randomly assorted into two groups'.
Blinding (performance bias and detection bias) All outcomes	High risk	No placebo. Although eligibility and enrolment into the study was done on a post‐operative histological specimen (T2/T3), given that patients also received adjuvant (post‐operative) chemotherapy in this trial there was a potential risk of performance bias in the administration of adjuvant chemotherapy which could have had an impact on overall survival.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Reasons for patient exclusions given (Nb. Three patients with inadequate drug delivery were removed from the analysis, and was not an intention to treat sample. However, given the small numbers it is unlikely this had any effect on the outcome). No patients lost to follow up. Mean follow up of 10.7 years.
Selective reporting (reporting bias)	Unclear risk	Protocol not available. Unclear what the primary outcome of the trial was (overall survival vs. rates of reflux oesophagitis/appetite loss).
Other bias	Low risk	No other concerns identified.