Possible Earlier Diagnosis of Ulcerative Colitis-Associated Neoplasia: A Retrospective Analysis of Interval Cases during Surveillance

Abstract

Background: Early detection of ulcerative colitis-associated neoplasia (UCAN) is often difficult. The aim of this study was to clarify the morphology of initial UCAN.

Methods: White-light colonoscopy images obtained within the 2 years before UCAN diagnosis were retrospectively reviewed. The primary endpoint was the frequency of visible or invisible neoplasia on the endoscopic images before UCAN diagnosis. The secondary endpoints were comparisons of (1) visible or invisible neoplasia on initial endoscopic images of early-stage and advanced cancers, (2) the clinical backgrounds of patients in whom neoplasia was visible or invisible on initial endoscopic images, and (3) the clinical backgrounds of patients with distinct and indistinct UCAN borders.

Results: Of the 27 UCAN lesions (11 early-stage; 16 advanced-stage), 25.9% (n = 7) were initially visible and 74.1% (n = 20) were invisible. The mean interval between the last surveillance colonoscopy and UCAN diagnosis was 14.5 ± 6.7 months. Of early-stage cancers, 18.2% (n = 2) were visible and 81.8% (n = 9) were invisible. Of advanced-stage cancers, 31.3% (n = 5) were visible and 68.8% (n = 11) were invisible. Invisible lesions were significantly more common in the rectum (p = 0.011) and tended to be more common in patients with inflammation and left-sided colitis (p = 0.084, p = 0.068, respectively). Patients with indistinct UCAN borders were significantly more likely to present with inflammation than those with distinct UCAN borders (p = 0.021).

Conclusion: More careful surveillance is needed because rectum lesions and inflammation are difficult to identify as neoplasia even within the 2 years before a UCAN diagnosis.

Keywords: colorectal cancer; interval cancer; surveillance; ulcerative colitis; ulcerative colitis-associated neoplasia.

Figure 1

A visible lesion that progressed to early-stage cancer. (a) An image obtained 12 months before cancer diagnosis reveals background mucosa in the active phase and slightly elevated lesions with indistinct border in the sigmoid colon. Although the tumor was recognized, the biopsy revealed no neoplastic changes and colonoscopy was performed every few months. (b) At the time of the cancer diagnosis, the background mucosa was in the remission phase and slightly elevated lesions with indistinct border was observed. Histopathological findings indicated a well-differentiated adenocarcinoma, pTis.

Figure 2

An invisible lesion that progressed to early-stage cancer. (a) At 14 months before the cancer diagnosis, the background mucosa was in the active phase and finely granular mucosa was observed in the Ra. A biopsy was not performed. (b) At the time of cancer diagnosis, the background mucosa was in the active phase, and a villous and granular elevated lesion and an ulcer were visible. The histopathological findings indicated a well-differentiated adenocarcinoma, pTis.

Figure 3

An invisible lesion that progressed to early-stage cancer. (a) At 14 months before the cancer diagnosis, the background mucosa was in the remission phase, and a red, flat lesion (white arrow) was observed in the Ra. A biopsy of the same site showed low grade dysplasia. (b) At the time of cancer diagnosis, superficial elevated lesion with distinct border (black arrow) was observed. Histopathological findings indicated a well-differentiated adenocarcinoma, stage pTis.

Figure 4

A visible lesion that progressed to advanced-stage cancer. (a) At 17 months before the cancer diagnosis, the background mucosa was mildly active, and slightly elevated lesion was observed in the sigmoid colon. Although the biopsy revealed tubular adenoma, medical treatment was intensified because of the exacerbation of UC. (b) At the time of cancer diagnosis, the background mucosa was in the mildly active phase, and elevated lesion with indistinct border was observed. The histopathological findings indicated a well to moderately differentiated adenocarcinoma, pT4.

Figure 5

An invisible lesion that progressed to advanced-stage cancer. (a) At 15 months before the cancer diagnosis, the background mucosa was in remission. (b) At the time of cancer diagnosis, the background mucosa was in the remission, and an ulcer in the Rb and irregular elevated lesion with indistinct border in the Rb were observed. The histopathological findings indicated an endocrine cell carcinoma, pT4.