Chromoendoscopy with Indigocarmine Improves the Detection of Adenomatous and Nonadenomatous Lesions in the Colon

Background and Study Aims: Depressed early cancers and flat adenomas have a high potential for malignancy with possible infiltrating growth, despite the small size of the lesion. Japanese investigators have shown that early diagnosis and classification of these lesions is possible with the help of chromoendoscopy. The aim of this study, therefore, was to evaluate the usefulness of chromoendoscopy during routine colonoscopy.

Patients and Methods: During routine colonoscopy, vital staining with indigocarmine solution (0.4 %, 1 - 10 ml) was performed on all visible lesions in 100 consecutive patients without visible inflammatory changes. If findings on macroscopic examination were unremarkable, the sigmoid colon and rectum were stained with indigocarmine over a defined segment (0 - 30 cm ab ano) and inspected for lesions visible only after staining. Each lesion was classified with regard to type (polypoid, flat, or depressed), position and size. The staining pattern was classified according to the pit pattern classification.

Results: A total of 52 patients had 105 visible lesions (89 polypoid, 14 flat and two depressed). The mean size of the lesions was 1.4 cm. Among the 48 patients with mucosa of normal appearance, 27 showed 178 lesions after staining (176 flat, two depressed) with a mean size of 3 mm. On histological investigation, 210 lesions showed hyperplastic or inflammatory changes, 67 were adenomas and six were cancers. Use of the pit pattern system to classify lesions (adenomatous, pit patterns III-V; nonadenomatous, pit patterns I-II) was possible, with a sensitivity of 92 % and a specificity of 93 %. Lesions with pit patterns III - V showed higher rates of dysplasia.

Conclusions: Chromoendoscopy allows easy detection of mucosal lesions in the colon and facilitates visualization of the margins of flat lesions. This technique unmasks multiple mucosal lesions which are not identified by routine video colonoscopy. The pit pattern seen after staining allows differentiation between hyperplastic and adenomatous lesions which may have consequences with regard to the endoscopic interventions needed.

References

• 1 Hayakawa M, Shimokawa K, Kusugami K, et al. Clinicopathological features of superficial depressed-type colorectal neoplastic lesions.  Am J Gastroenterol. 1999;  4 944-949
• 2 Saitoh Y, Obara T, Watari J, et al. Invasion depth diagnosis of depressed type early colorectal cancers by combined use of videoendoscopy and chromoendoscopy.  Gastrointest Endosc. 1998;  48 362-370
• 3 Kudo S, Tamura S, Nakajima T, et al. Diagnosis of colorectal tumorous lesions by magnifying endoscopy.  Gastrointest Endosc. 1996;  44 8-14
• 4 Kudo S, Kusaka H, Yamano H, et al. Characteristics of depressed early colorectal carcinoma [abstract].  Gastrointest Endosc. 1999;  49 2
• 5 Mitooka H, Fujimori T, Maeda S, et al. Minute flat depressed neoplastic lesions of the colon detected by contrast chromoscopy using an indigo carmine capsule.  Gastrointest Endosc. 1995;  41 453-459
• 6 Kudo S, Kashida H, Nakajima T, et al. Endoscopic diagnosis and treatment of early colorectal cancer.  World J Gastroenterol. 1997;  21 694-701
• 7 Axelrad A M, Fleischer D E, Geller A J, et al. High resolution chromoendoscopy for the diagnosis of diminutive colon polyps: implications for colon cancer screening.  Gastroenterology. 1996;  110 1253-1258
• 8 Karita M, Cantero D, Okita K. Endoscopic diagnosis and resection treatment for flat adenoma with severe dysplasia.  Am J Gastroenterol. 1993;  88 1421-1423
• 9 Trecca A, Fujii T, Kato S, et al. Small advanced colorectal adenocarcinomas: report on three cases.  Endoscopy. 1998;  30 493-495
• 10 Kaneko K, Kurahashi T, Makino R, et al. Growth patterns of superficially elevated neoplasia in the large intestine.  Gastrointest Endosc. 2000;  51 443-450
• 11 Kuramoto S, Mimura T, Yamasaki K, et al. Flat cancers do develop in the polyp-free large intestine.  Dis Colon Rectum. 1997;  40 534-539
• 12 Fujii T, Rembacken B J, Dixon M F, et al. Flat adenomas in the United Kingdom: are treatable cancers being missed?.  Endoscopy. 1998;  30 437-443
• 13 Rembacken B J, Fujii T, Cairns A, et al. Flat and depressed colonic neoplasms : a prospective study of 1000 colonoscopies in the UK.  Lancet. 2000;  355 1211-1214
• 14 Tanaka S, Haruma K, Hirota Y, et al. Clinical significance of detailed observation for colorectal neoplasia using the high-resolution or magnifying videocolonoscope [abstract].  Endoscopy. 1999;  31 1, E52
• 15 Kurahashi T, Kaneko K, Konishi K, et al. The usefulness of magnifying colonoscopy for differentiation of colorectal lesions [abstract].  Endoscopy. 1999;  31 1, E71
• 16 Tanaka S, Haruma K, Hirota Y, et al. Clinical significance of detailed observation for colorectal neoplasia using the high-resolution or magnifying videocolonoscope. 7th United European Gastroenterology Week 1999, Rome, Italy. Abstract P0456E. 
• 17 Saito H, Kato S, Sano Y. The distribution of hyperplastic polyps in the large intestine [abstract].  Gut. 1999;  45 5, A305