Natural history of superficial depressed colorectal cancer: Retrospective radiographic and histologic analysis

PURPOSE: To characterize the growth and developmental changes of superficial depressed colon cancer by using retrospective radiographic and histologic data. MATERIALS AND METHODS: In a retrospective study, the radiographs in patients with nine superficial depressed and those with 12 elevated (sessile or semipedunculated) colon cancers were analyzed. RESULTS: The initial superficial depressed lesions were 11.7 mm (mean) in diameter and took an average of 32.3 months to double in size. The initial elevated Lesions were 15.7 mm (mean) in diameter and took an average of 8.6 months to double in size. The initial size of the former was not statistically significantly different from that of the latter; however, the doubling time of the superficial depressed cancers was statistically significantly slower than that of the elevated cancers. Superficial depressed cancers did not have concomitant ant adenomatous components, did not develop rapidly into advanced cancer, and did not change greatly from their original configuration; their growth rate was rather slow. Histologically, superficial depressed cancers showed a nonpolypoid growth pattern. CONCLUSION: Superficial depressed cancer develops more slowly than does elevated cancer, and this development follows a nonpolypoid growth pattern.