Use of Multidetector-row CT Colonography for Detection of Colorectal Neoplasia in Patients Referred via the Department of Health “2-Week-Wait” Initiative
Introduction
In an attempt to prevent delay in the diagnosis and treatment of cancer, the UK government has proposed that “everyone with suspected cancer will be able to see a specialist within 2 weeks of their GP deciding that they need to be seen urgently and requesting an appointment” [1]. This standard is now applicable to all common cancers, including colorectal, the second most common cause of cancer-related death in the UK [2]. On the basis of a comprehensive literature review, the Association of Coloproctology of Great Britain and Ireland devised six symptom complexes estimated to account for up to 90% of patients with colorectal cancer [3], which have been used to identify high-risk patients. However, the relatively low specificity of some symptoms and variability in interpreting these guidelines has meant that many referred patients have no significant colonic abnormality. Indeed, initial experience suggests that only 9–20% of referred patients have colorectal cancer 4, 5, 6.
Most patients referred via the 2-week-wait initiative merit some form of whole-colon investigation, but although colonoscopy remains the most sensitive test, it is expensive, resource intensive [7], time-consuming, and has an associated small, but well recognized morbidity and mortality [8]. Complications related to sedation are increased in the elderly 9, 10, highly relevant as two of the six symptom complexes are specific to patients over 60 years [3]. Furthermore the average national caecal intubation rate may be as low as 57% [11]. Barium enema remains the standard radiological alternative to colonoscopy, but is less sensitive [12]. Computed tomography (CT) colonography is a relatively new technique that has similar advantages of safety, is well tolerated [13], and has reported sensitivity for colonic neoplasia surpassing barium enema and approaching conventional endoscopy 14, 15, 16, 17. We hypothesized that CT colonography might be a practical first-line investigation for those referred under the 2-week-wait initiative and tested this against colonoscopy as the gold standard.
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Patients and Methods
Our local ethical review committee approved the study and all participants gave informed written consent. At our institution, all 2-week-wait initiative referrals are faxed by general practitioners to a single dedicated facsimile machine, from which patient details are recorded and outpatient appointments organized. Consecutive patients were directed, if possible, to a single weekly morning colonoscopy list. Between May 2001 and June 2002 a total of 86 “2-week wait” patients were referred for
Results
The mean time spent by patients in the CT suite was 23.2 min (SD 5.3, range 13–33 min) with a mean examination time of 8.8 min (SD 2.6, range 9–17 min). The mean reporting time for CT colonography was 13.9 min (SD 4.1, range 8–30 min). No patient undergoing CT colonography refused subsequent colonoscopy. The mean time for colonoscopy was 24.1 min (SD 8.1, range 14–38 min). Colonoscopy was complete in 49 patients (91%). Reasons for non-completion were obstructing tumour in two patients (sigmoid
Discussion
The prognosis of colorectal cancer is related to the histological stage [21], and it is believed that earlier diagnosis may improve disease specific mortality. Recognizing that waiting times for hospital out-patient appointments were frequently too long [22], the UK government initiated the 2-week-wait standard in an attempt to ensure that patients suspected of having cancer are seen quickly and efficiently. Unfortunately, symptoms of colorectal cancer are non-specific and the majority of
Acknowledgments
This research was supported by a research fellowship from the Royal College of Radiologists, the Wexham Gastrointestinal Trust, and by General Electric Medical Systems, Slough, UK.
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