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.
Our study was undertaken as part of the Southern Co-operative Program for the Prevention of Colorectal Cancer (SCOOP), a joint South Australian program of the Flinders Medical Centre, the Repatriation General Hospital and the Southern Division of General Practice, which was established in June 1999. The aims of the program are to disseminate NHMRC guidelines on colorectal cancer prevention to medical practitioners in the southern region of Adelaide, and to integrate the hospital aspects of colorectal cancer prevention with primary care practice.
Two indications for surveillance colonoscopy were audited before and after dissemination of the NHMRC guidelines in January 2000.
The timing of a repeat colonoscopy after a polypectomy; and
The timing of colonoscopy for patients with an "above average" risk of colorectal cancer, based on family history of the disease. (Patients from families with hereditary non-polyposis colorectal cancer [HNPCC] or familial adenomatous polyposis [FAP] were not included.)
For the timing of repeat colonoscopy after a complete polypectomy, NHMRC guidelines recommend a colonoscopy interval of 5 years for patients with one or two small (< 10 mm) tubular adenomas; and 3 years if there were more than two tubular adenomas, or if the adenoma measured 10 mm or more, or if histological examination showed a villous component.
In families with a history of colorectal cancer in a first-degree relative (< 55 years of age), the NHMRC recommends 5-yearly colonoscopy surveillance starting at age 50, or 10 years younger than the index case. For those with a first-degree relative affected over the age of 55, and no other affected relatives, the NHMRC does not recommend colonoscopic screening.
The 100 consecutive patients referred before and after the intervention had similar mean ages and sex distributions (57 men and 43 women aged 63 [SD, 11.3] years v 59 men and 41 women aged 62 [SD, 11.1] years). After the intervention, the proportion of surveillance decisions matching the guidelines increased from 38% to 96% (P < 0.05, χ2 test). The reasons for the change were: repeat colonoscopy was requested too soon after polypectomy (37% of patients); a repeat colonoscopy was requested too late after polypectomy (1% of patients); or the decision was deferred until clinic review, the patient was lost to follow up or no decision was made (24% of patients) (Box 2). The mean time to repeat colonoscopy after polypectomy increased from 2.7 to 3.5 years (P = 0.005; unpaired t-test; 95% CI, 2.69–14.60).
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
Received 10 May 2001, accepted 18 January 2002
Abstract
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.