Rodríguez‐Moranta 2006

Methods	RCT, Accrual: 1997 to 2001 Multicentred, stratified for centre, location, and stage Setting: hospital Follow‐up: 48 months
Participants	259 participants (161 men and 98 women), stage II and III colon and rectal cancer Country: Spain
Interventions	The experimental group were seen with history, examination, and bloods (including CEA), US/CT, CXR, and colonoscopy. The control group were seen with history, examination, and bloods (including CEA).
Outcomes	Local recurrence Curative reoperation rates Overall survival
Notes	Experimental group Seen with history, examination, and bloods (including CEA) at 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, and 60 months US/CT at 6, 12, 18, 24, 30, 36, 42, 48, and 56 months CXR and colonoscopy at 12, 24, 36, 48, and 56 months Control group Seen with history, examination, and bloods (including CEA) at 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, and 60 months
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Patients were stratified according to centre, location (colon/rectum), and TNM stage (II/III); thereafter, patients were randomly allocated to either simple or intensive surveillance strategies by means of sealed envelopes containing computer‐generated random numbers." Comment: we judged this method of sequence generation to be at low risk of bias.
Allocation concealment (selection bias)	Low risk	Quote: "Patients were randomly allocated to either simple or intensive surveillance strategies by means of sealed envelopes containing computer‐generated random numbers. Random assignment was centralized at the Hospital Clinic." Comment: sequence generation was reported to be remote, but as the study gave no further details, we rated this domain as at unclear risk of bias.
Blinding of participants and personnel	Unclear risk	Participants: blinding to treatment arm was not mentioned, but this would have been difficult to do. As history and examination was performed for both arms, it is unlikely to have been a cause of bias for objective outcomes. The study reported no subjective outcomes. Personnel: not mentioned, unlikely to have been done. The follow‐up schedule was specified (see Table 3, page 387). This would reduce the risk of bias. Knowledge of study arm could influence clinical decisions made on the basis of history and clinical findings, to influence further investigations, which could introduce potentially introduce bias. We therefore judged this domain to be at high risk of bias.
Blinding of outcome assessment	Unclear risk	The study did not mention blinding of outcome assessment, but it is unlikely to have been a source of bias. Therefore, we judged this domain to be at low risk of bias.
Incomplete outcome data (attrition and exclusions)	Low risk	Quote: "During the study period, 270 patients were included. Eleven patients (4%) were excluded after random assignment because of inadequate initial assessment of tumor stage (eight had distant metastases and three had a stage I tumor). Consequently, 259 participants constitute the basis of this study." Exclusions: these exclusions were reported by arm: Intensive: 2 with Stage I s, 4 with Stage IV s Minimal: 1 with Stage I, 4 with Stage IV s This is unlikely to have introduced bias, as the reasons are similar for exclusions in each arm and the numbers excluded in each arm are similar. Attrition: quote (page 388): "No patient was lost to follow‐up" Comment: this is unlikely to have introduced bias.
Selective reporting (reporting bias)	Unclear risk	Outcomes specified in the methods Survival Resectable recurrence Outcomes actually reported in the paper Overall survival, survival by stage and location Cause‐specific survival Recurrence Time to relapse Type of relapse Resectable recurrences Resectable recurrences by stage and location Method of detecting first recurrence Metachronous recurrences Cost of follow‐up Cost per resectable recurrence We were not able to review the protocol, so we judged this domain to be at unclear risk of bias.
Other sources of bias	Unclear risk	We detected no other bias.