Applying evidence-based guidelines improves use of colonoscopy resources in patients with a moderate risk of colorectal neoplasia

Peter A Bampton, Jayne J Sandford and Graeme P Young
Med J Aust 2002; 176 (4): 155-157. || doi: 10.5694/j.1326-5377.2002.tb04344.x
Published online: 18 February 2002


Objectives: To determine whether applying National Health and Medical Research Council (NHMRC) guidelines for colorectal cancer prevention would reduce the number of follow-up colonoscopies.

Design: A prospective audit of colonoscopic surveillance decisions before and after the intervention.

Setting: The endoscopy suite at a metropolitan tertiary hospital three months before and after January 2000.

Intervention: Dissemination of NHMRC guidelines, and supervision of application of the guidelines by a nurse coordinator.

Subjects: We compared colonoscopic surveillance decisions before and after the intervention in two groups of 100 consecutive patients after polypectomy and in two groups of 50 consecutive patients with a family history of colorectal cancer after a normal colonoscopy.

Main outcome measures: Change in concordance of decisions with NHMRC guidelines; and effect on number of follow-up colonoscopies.

Results: After the intervention, the proportion of postpolypectomy surveillance decisions matching the guidelines increased from 37% to 96% (P < 0.05). The mean time to repeat colonoscopy after polypectomy increased from 2.7 to 3.5 years (P < 0.005) (ie, a 23% reduction in the number of postpolypectomy surveillance colonoscopies performed per year). Likewise, the proportion of family-history surveillance decisions matching the guidelines increased from 63% to 96%. Adhering to the guidelines resulted in a 17% reduction in colonoscopies performed on the basis of a family history of colorectal cancer.

Conclusions: Supervised application of evidence-based guidelines to a colorectal cancer surveillance program significantly reduces the number of surveillance colonoscopies performed.

Implementation of any form of population screening for colorectal cancer — faecal occult blood testing, flexible sigmoidoscopy or colonoscopy — will place greater demands on colonoscopy resources.1-6 Reducing the number of colonoscopies currently performed would make resources available for such a screening program.

In 1999, after an evidence-based review, the Australian National Health and Medical Research Council (NHMRC) released best-practice guidelines for the prevention, management and detection of colorectal cancer.7 Previous studies have suggested that general practitioners do not uniformly comply with national guidelines,8 and we suspect a similar problem of guideline compliance would be found in specialist practice. Accordingly, we determined whether monitoring the application of NHMRC recommendations for colonoscopic follow-up in two groups of patients with moderate risk of colorectal cancer (those who have had a polyp excised at colonoscopy and those with a family history of colorectal cancer) would reduce the number of surveillance colonoscopies being performed in a public hospital.

Surveillance for family history

The 50 consecutive patients referred before and after the intervention had similar mean ages and sex distributions (16 men and 34 women, aged 53 [SD, 10.5] years v 19 men and 31 women, aged 50 [SD, 11.2] years). After the intervention, the proportion of surveillance decisions matching the guidelines increased from 62% to 96% (Box 2). In seven patients (14%) referred before the intervention, "family history" was based on only one first-degree relative affected over the age of 55 years. According to the NHMRC guidelines, such patients have average to slightly above average risk and do not need colonoscopic surveillance. There was no significant increase in the mean time to repeat colonoscopy in this group (from 4.7 to 4.8 years). The effect of the intervention in this group was therefore to reduce the number of patients having colonoscopic surveillance rather than increase the time interval for repeat colonoscopy.


To determine the optimal interval between colonoscopies after polypectomy, the NHMRC guidelines rely on a retrospective study of patients from the 1950s and 60s9 and prospective data from the US National Polyp Study.10,11 The recommendation for colonoscopy in patients with a family history of colorectal cancer is accorded Level 3 evidence by the NHMRC guidelines, and is supported by cohort studies.12-15 The guidelines do not recommend colonoscopy screening if the subject has only one affected relative aged 55 years or over, because of a low yield of neoplasia from surveillance in this group.16-18

Our study showed that, in a public hospital, 37% of patients after polypectomy and 6% of patients with a family history of colorectal cancer were having their repeat colonoscopy at inappropriately short time intervals. Moreover, 14% of patients having a colonoscopy because of a family history of colorectal cancer did not require colonoscopy on these grounds.

Before the introduction of the nurse coordinator, the decision about timing of repeat colonoscopy was made either at the time of the initial colonoscopy, or delayed until the patient was seen in the outpatient clinic. If the decision was made at the time of initial colonoscopy, when the histological results would not yet be available, two problems arose: inappropriate follow-up of non-neoplastic polyps, and uncertainty about the correct interval for repeat colonoscopy (depending on the presence of a villous component or whether polyp removal was complete).

If the decision was deferred until a follow-up consultation in the outpatient clinic, then not only did this further overload the consultative service, but a significant number of patients did not attend and were lost to follow-up. After introduction of the nurse coordinator, every patient and his or her general practitioner were given a recommendation about follow-up.

Our study shows that applying NHMRC guidelines to colonoscopy practice, supervised by a nurse coordinator, significantly reduces surveillance colonoscopies performed in patients after polypectomy or those with a family history of colorectal cancer.

Received 10 May 2001, accepted 18 January 2002

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