Site distribution of colonic adenomas and carcinomas in relation to colonic flexures.

To minimize the chance of overlooking colonic tumours, 'short segments' of the colon were defined and examined on barium enema films in relation to the distribution of colonic tumours. Films of 299 histologically proven adenomas and carcinomas from 265 consecutive patients were used. No significant differences in distribution were noted between the adenomas and carcinomas. The distance of tumours from distal minor flexures was within seven centimetres in 80% of lesions in the transverse colon, five centimetres in 80% of lesions in the descending colon, and four and six centimetres respectively for 80 and 95% of sigmoid colon lesions. In the cecum plus ascending colon 75% of the lesions were located within seven centimetres from the cecal pole.