Pancolonic indigo carmine dye spraying for the detection of dysplasia in ulcerative colitis

Abstract

Background and aims: Colonoscopic surveillance for cancer in longstanding extensive ulcerative colitis relies heavily on non-targeted mucosal biopsies. Chromoendoscopy can aid detection of subtle mucosal abnormalities. We hypothesised that routine pancolonic indigo carmine dye spraying would improve the macroscopic detection of dysplasia and reduce the dependence on non-targeted biopsies. Patients and methods: One hundred patients with longstanding extensive ulcerative colitis attending for colonoscopic surveillance underwent ''back to back'' colonoscopies. During the first examination, visible abnormalities were biopsied, and quadrantic non-targeted biopsies were taken every 10 cm. Pancolonic indigo carmine (0.1%) was used during the second colonoscopic examination, and any additional visible abnormalities were biopsied. Results: Median extubation times for the first and second colonoscopies were 11 and 10 minutes, respectively. The non-targeted biopsy protocol detected no dysplasia in 2904 biopsies. Forty three mucosal abnormalities (20 patients) were detected during the pre-dye spray colonoscopy of which two (two patients) were dysplastic: both were considered to be dysplasia associated lesions/masses. A total of 114 additional abnormalities (55 patients) were detected following dye spraying, of which seven (five patients) were dysplastic: all were considered to be adenomas. There was a strong trend towards statistically increased dysplasia detection following dye spraying (p = 0.06, paired exact test). The targeted biopsy protocol detected dysplasia in significantly more patients than the non-targeted protocol (p = 0.02, paired exact test). Conclusions: No dysplasia was detected in 2904 non-targeted biopsies. In comparison, a targeted biopsy protocol with pancolonic chromoendoscopy required fewer biopsies (157) yet detected nine dysplastic lesions, seven of which were only visible after indigo carmine application. Careful mucosal examination aided by pancolonic chromoendoscopy and targeted biopsies of suspicious lesions may be a more effective surveillance methodology than taking multiple non-targeted biopsies.

Ulcerative colitis and cancer

“…Furthermore, percentage of patients with aneuploidy increases after duration of more than 10 years compared to patients with dysplasia findings that are found more often with disease duration of over 20 years [35]. Other studies confirmed that DNA aneuploidy is stable, widely spread (hence sampling error is minimal), may precede dysplasia (hence represents an early marker), and is evident 10 years after onset of colitis in young patients [23,25,55,63,68,75,76]. In addition to duration, aneuploidy correlates with extent of disease and is associated with total colitis [23,74].…”

“…A pre-operative diagnosis of dysplasia of any grade is associated with a 50% probability of associated invasive carcinoma [49]. Dysplasia may be not visible or may be sessile, flat, or minimally elevated and require careful examination to be detected and numerous biopsies are required to confirm its presence [63,68]. Magnifying or high-resolution endoscopy after spraying of dye (indigo carmine, methylene blue, crystal violet) to high light architectural irregularities improves sensitivity of examination of surface mucosa especially when dysplastic changes are subtle, facilitates discovery of dysplasia/CC, and allows targeted biopsies [68][69][70][71].…”

“…Dysplasia may be not visible or may be sessile, flat, or minimally elevated and require careful examination to be detected and numerous biopsies are required to confirm its presence [63,68]. Magnifying or high-resolution endoscopy after spraying of dye (indigo carmine, methylene blue, crystal violet) to high light architectural irregularities improves sensitivity of examination of surface mucosa especially when dysplastic changes are subtle, facilitates discovery of dysplasia/CC, and allows targeted biopsies [68][69][70][71]. The dye not only enhances the structural details of the mucosa and pit patterns (openings of glandular pits), but also provides better correlation between endoscopic assessment of degree and extent of inflammation and histopathologic findings compared to conventional endoscopy [33,68,71].…”

“…Aneuploidy represents an early alteration during neoplastic transformation in UC [24,35,68,75]. Holzman et al [35] noted that aneuploidy is present in 8.7% of patients with UC and the frequency increased with increased duration of the disease (>10 years).…”

The efficacy of autofluorescence imaging in the diagnosis of colorectal diseases

“…However, the standard strategy of surveillance colonoscopy seems to be associated with risks such as bleeding and lower cost-effectiveness. Several reports have indicated that chromoendoscopy with targeted mucosal biopsies was superior to the standard strategy for detecting dysplasia in IBD patients [59,60]. Although this is a time-saving and cost-effective method, it requires the endoscopist to possess a certain skill and experience level [61].…”