BACKGROUND: Retrospective studies showed that cancers proximal (PC) to the splenic flexure are usually not accompanied by adenomas (AD) distal to the splenic flexure indicating that flex sig would be ineffective as a screening tool for advanced proximal neoplasia. AIMS: 1. Prospectively identify distal colon findings in pts with PC to ensure that adequate clearing is performed. 2. Determine if the results apply in average-risk persons by collecting family history. Pts with positive family history often undergo colonoscopy in any case. 3. Determine the association of distal AD with PC according to size of AD. METHODS: Prospective multicenter clearing colonoscopy in consecutive pts with PC. RESULTS: 124 pts with PC (105 with negative family history) underwent prospective clearing colonoscopy. Of the 105 with negative family history of cancer or polyps, 54 were male, mean age 70.9y, range of 29-96y. 37 (35%) had either CA alone (n=2), AD only (n=30), or both (n=5). Of those with only AD distal to the splenic flexure, the 30 pts had a total of 47 AD distal to the splenic flexure. The largest distal AD was ≥ 1cm in 17 pts, 6-9mm in 4 pts and ≤5mm in 9 pts. 10 pts had only a single tubular AD distal to the splenic flexure. 7 pts had AD only in the descending colon, possibly out of reach of flex sig. 8 pts had only hyperplastic polyps distal to the splenic flexure. Of 19 pts with a family history of CA or AD, 8 had AD only (6 with one or more AD ≥ 1cm in size) and 1 had both CA and AD distal to the splenic flexure. SUMMARY: 1. Most average-risk pts with PC have no neoplasia distal to the splenic flexure when prospectively evaluated, similar to the results of retrospective studies. 2. Of those with distal AD, a high percentage have large AD. 3. A single small tubular AD in the distal colon and only hyperplastic polyps distally have similar weak associations with PC. CONCLUSION: Only screening by colonoscopy or other effective full colon evaluation can reliably identify proximal colon cancer.
|Original language||English (US)|
|State||Published - Dec 1 1998|
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging