Chia Chuin Yau
South tynside and Sunderland NHS Trust, United Kingdom.
Title: Missed Colorectal Cancer Following Colonoscopy, Flexible-Sigmoidoscopy, CT Colonography or CT Abdomen in a District Hospital
Biography
Biography: Chia Chuin Yau
Abstract
Introduction
Colorectal cancer (CRC) is the 4th most common cancer in the UK, accounting for 12% of all newly diagnosis cancer. Early diagnosis improves survival and avoiding delayed diagnosis is crucial. We look report the miss rate of CRC in our Trust following investigation of symptomatic, asymptomatic and surveillance patients.
Methods
This is a retrospective review of CRC cases diagnosed between April 2017 and April 2018. We obtain evidence of investigations done in the 3 years prior to diagnosis from endoscopy record, OpenNet patient reports and Radiology report. Evidence regarding previous investigations includes colonoscopy, flexible sigmoidoscopy, computer tomographic colonography (CTC) and computer tomographic abdomen (CT abdomen) was collected.
Results
115 patients were identified of which 11 patients had been investigated within the 3 years prior to diagnosis. 9/11 (82%) had a prior CT abdomen with contrast. 4/9 (44%) were having planned follow up following previous surgery for CRC with average time from prior test of 9 months. 5/9 (56%) patients had CT abdomen for anaemia, rectal bleeding, acute pancreatitis, chronic cough and pleural effusion with an average time from prior test to diagnosis of 12 months.
1/11 patients (9%) had an earlier colonoscopy. This patient was undergoing annual polyp surveillance. At the prior colonoscopy 18 polyps were removed (tubular adenomas) with plans to complete clearance at a later stage. On this planned follow up colonoscopy 3 months later a transverse colon cancer was diagnosis.
1/11 (9%) patient had a flexible-sigmoidoscopy for left iliac fossa pain and fresh rectal bleeding 18 months before diagnosis. Patient was diagnosed with malignant of appendix unlikely to be related to symptoms.
None of the missed cases were from CTC.
Conclusion
Colonoscopy and CTC is the most reliable test for detecting CRC. CT abdomen have higher miss rates compared to the above. Patients with bowel symptoms with good functioning performance status should proceed with colonoscopy. Non purgative faecally tagged CTC remains an excellent alternative for patients who have comorbidities or not able to tolerate colonoscopy. Clinician should be reminded of the limitations of CT abdomen in detecting CRC. All patients who had curative resection for CRC should be offered a surveillance colonoscopy at 1 year after initial treatment in additional to CT.