RETROSPECTIVE ENDOSCOPIC STUDY OF DEVELOPMENTAL AND CONFIGURATIONAL CHANGES OF EARLY COLORECTAL CANCER: EIGHT CASES AND A REVIEW OF THE LITERATURE

Background: A retrospective endoscopic follow-up study was conducted to elucidate the development of minute or superficial-type cancers. Methods: The development of eight colorectal cancers that were followed up by endoscopy was evaluated. Results: (i) Cancer with high-grade atypia frequently developed from lesions diagnosed histologically by biopsy as adenoma; (ii) two polypoid adenomas developed into invasive cancers with non-polypoid configuration; (iii) a superficial elevated-type cancer with high-grade atypia remained a mucosal cancer for more than 1 year; (iv) a superficial depressed (SD)-type cancer that had a concomitant adenomatous component grew slowly, maintaining the same configuration for more than 2 years. Another SD-type cancer grew rapidly to an advanced cancer; and (v) a superficial elevated adenoma developed into a IIa + IIc-type submucosally invasive cancer while maintaining the size of the initial tumor. From the analysis of the literature, 35 lesions were collected, but it was impossible to speculate which specific type of tumor grew rapidly. Conclusions: From the endoscopic observations of the present study and the review of the literature, developments of superficial type cancers were diverse, sessile-type cancers with marked configurational change, and early cancers developed slowly, although the speed of their growth accelerated according to the downward invasion of the cancer.