Is whole colonic imaging necessary for symptoms of change in bowel habit and/or rectal bleeding?

AIM: Following the introduction of a 2-week-wait (2ww) cancer pathway, many units are triaging patients with change in bowel habit (CIBH) and/or rectal bleeding (RB) straight to colonoscopy. Evidence suggests that right-sided colonic cancer does not present with these symptoms, hence imaging the left colon only is satisfactory. If this were substantiated, patients could be offered a flexible sigmoidoscopy (FS) alone. This study aimed to review presenting symptoms of patients diagnosed with a right-sided colonic malignancy and assess whether their tumours would be missed based on this practice.
METHOD: This is a retrospective analysis of patients who underwent curative resection for a proximal colonic malignancy over a 4-year period. Two-week-wait referral proforma and case notes were analysed for mode of presentation.
RESULTS: Of 206 elective right hemicolectomies performed, 20/206 (9.7%) patients presented in the absence of either iron deficiency anaemia or palpable abdominal mass. Twelve patients had polyposis identified in the left colon and eight patients had no left-sided colonic pathology. One patient had a strong family history of colon cancer (two first-degree relatives) in the group absent of left-sided pathology.
CONCLUSION: Twelve patients who had left-sided polyposis and one patient with a strong family history would have undergone whole colonic imaging based on current colorectal cancer management guidelines. The remaining seven patients with right-sided cancer would have been missed if FS were the only investigation used. Patients presenting on the 2ww with symptoms of a CIBH and/or RB can be adequately investigated with a FS with a 3% chance of missing a proximal cancer.