Retrospective radiographic analysis of nonpedunculated colorectal carcinomas with special reference to tumor doubling time and morphological change.

OBJECTIVE

Our aim was to characterize the development of nonpedunculated colorectal carcinomas by retrospective radiographic analysis, with special reference to tumor doubling time and morphological change.

METHODS

Eleven colorectal carcinomas, which were observed for >6 months by barium enema examinations, were collected and retrospectively reviewed. There were five early and six advanced carcinomas, including submucosally invasive, superficial depressed carcinomas.

RESULTS

Mean diameter of lesions at initial barium enema examination was 13.5 mm (early, 10.4 mm; advanced, 16.0 mm) and that at final barium enema examination was 30.9 mm (early, 18.2 mm; advanced, 41.5 mm). Initial morphology of the lesions was superficial in three, sessile in seven, and semipedunculated in 1. There was no pedunculated lesion. Macroscopic morphology of the five early carcinomas was superficial depressed (IIc) in two cases, mostly depressed but partly elevated (IIc+IIa) in one case, and superficial elevated with a depressed component (IIa+IIc) in two cases; all of the advanced carcinomas were of the ulcerated type. Mean doubling time was 6.8 months (early, 9.4 months; advanced, 4.7 months). Early carcinomas had significantly longer doubling times than advanced carcinomas (p = 0.017, Wilcoxon's text). The lesions with the longest doubling times were superficial depressed lesions.

CONCLUSIONS

Early carcinomas have longer doubling times than advanced carcinomas. Most nonpedunculated colorectal carcinomas grow without significant morphological changes. Superficial depressed type tumors grow slowly, maintaining their macroscopic morphology.