Background and aims: Early colorectal cancer (CRC) with submucosal deep (s.m.-d.) invasion should not be treated with endoscopic mucosal resection due to the higher incidence of lymph-node metastasis. It is, therefore, clinically important to accurately diagnose s.m.-d. lesions before treatment.
Methods: We analyzed the endoscopic features, including pit patterns, of early CRC with s.m.-d. invasion observed using magnifying colonoscopy. We retrospectively investigated 379 cases of early CRC. Lesions were divided into three macroscopic subtypes (pedunculated type, sessile type and superficial type) based on endoscopic findings. Eight endoscopic factors were evaluated retrospectively for association with s.m. invasion and then compared to histopathological findings.
Results: The superficial type had a significantly higher frequency of s.m.-d. invasion (52.4% [77/147] vs 24.6% [14/57] and 39.4% [69/175], P-value < 0.05, respectively, for pedunculated and sessile types). Based on multivariate analysis, an independent risk factor for s.m.-d. invasion was the existence of an invasive pit pattern in sessile and superficial types (odds ratios of 52.74 and 209.67, respectively). Fullness was also an independent risk factor for s.m.-d. invasion in the superficial type (odds ratio = 9.25). There were no independent risk factors for s.m.-d. invasion in the pedunculated type.
Conclusion: High magnification pit pattern diagnosis proved to be useful for predicting s.m.-d. invasion in sessile and superficial types although it was not as helpful with the pedunculated type.