Pietra 1998

Methods	RCT Accrual: 1987 to 1990 Single centre trial Setting: university hospital Follow‐up: 60 months
Participants	207 consecutive participants (111 men, 96 women) who had curative resections for large bowel cancer; all had colonoscopy at 3 months post operation if had not been done preoperatively Exclusion criteria Dukes' A Liver metastases Severe concurrent illness precluding follow‐up or treatment of recurrent disease Dukes' A: 0 Dukes' B: 122 Dukes' C: 85 Colon primary: 139 Rectal primary: 68 Country: Italy Setting: university hospital
Interventions	The experimental group were seen at 3, 6, 9, 12, 15, 18, 21, 24, 30, 36, 42, 48, 54, and 60 months, then annually thereafter. There was clinical examination, ultrasound, CEA, and CXR at each visit. Annual CT of the liver and colonoscopy were performed. The control group were seen at 6 and 12 months, then annually. At each visit, clinical examination, CEA, and ultrasound were performed. They had annual CXR, yearly colonoscopy, and CT scan.
Outcomes	Local recurrence Intramural recurrence Overall survival
Notes	Local recurrence: all local disease detectable at follow‐up, either alone or in conjunction with generalised recurrence Local recurrences were divided into extramural recurrences, where regrowth was located in and around the bed, including the pericolic fat, adjoining mesentery, or lymph nodes. Intramural recurrence: regrowth involving only the anastomosis A local recurrence was considered resected when no macroscopic/microscopic disease remained after surgery.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote (paragraph 3, page 1128): "were randomly assigned" The study reported no details of the method of sequence generation, which makes this domain at unclear risk of bias.
Allocation concealment (selection bias)	Unclear risk	The study reported no details, so we judged this domain to beat unclear risk of bias.
Blinding of participants and personnel	Low risk	Participant: not mentioned, unlikely to have introduced bias Assessors: quote (paragraph 3, page 1128): "The same clinical and instrumental tests CT included were performed whenever a patient of either group had symptoms suggestive of a possible recurrence of the disease (abdominal or perineal pain, altered bowel movements, change in fecal colour, or weight loss)." The prespecified follow‐up schedules and the lists symptoms to be investigated make this domain at low risk of bias.
Blinding of outcome assessment	Unclear risk	Blinding of outcome assessment was not mentioned. Local recurrence was the primary outcome measure so susceptible to bias.
Incomplete outcome data (attrition and exclusions)	High risk	Quote (page 1128): "Nine patients (3.8 per cent with Stage A s were excluded from the study because our previous reports demonstrated a low rate of recurrences in these cases. Other exclusion criteria were the presence of liver metastases (4 patients), even though these had been removed in apparently radical fashion during surgery on the primary, and the presence of severe illness that precluded intense follow‐up or treatment of recurrent disease (10 patients). The remaining 207 patients were enrolled in this study..." Exclusions: the exclusions were not reported by study arm. It is not clear from the report whether these exclusions occurred before randomisation. This means that the study potentially excluded 37/239 (15%) of those randomised. As little information has been provided, we have judged this to be at high risk of bias. Attrition: none reported, so we judged this domain at low risk of bias
Selective reporting (reporting bias)	Unclear risk	Outcomes specified in the methods Detection of local recurrence (LR) Resectability of LR Survival Outcomes actually reported in the paper LR (any LR, isolated LR, combined LR, interval LR, site of LR) Curative resection Metachronous primaries DFS for those having curative resections at recurrence Survival for all and for those who had curative resection of recurrence DFS We did not have access to the protocol, so judged this outcome to be at unclear risk of bias.
Other sources of bias	Unclear risk	We detected no other bias.