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Colorectal Adenomas. Santhat Nivatvongs MD Mayo Clinic Rochester Minnesota U. S.A. ADENOMATOUS POLYPS OF COLON AND RECTUM. Incidence Risk factors of an adenoma Natural history of an adenoma Serrated adenoma Colonoscopic polypectomy. AUTOPSY SURVEY 658 Adenomas. - PowerPoint PPT Presentation
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Colorectal Adenomas
Santhat Nivatvongs MD
Mayo Clinic
Rochester Minnesota
U. S.A.
ADENOMATOUS POLYPS OF COLON AND RECTUM
• Incidence
• Risk factors of an adenoma
• Natural history of an adenoma
• Serrated adenoma
• Colonoscopic polypectomy
AUTOPSY SURVEY658 Adenomas
Distribution (%)
Rectum 7 Other Findings
Sigmoid 17 Ave size 0.6 cm
Descending 9 Mean # 2.6
Transverse 28 increase # with age
Ascending 26 No increase in size with age
Cecum 13 11 invasive Ca ( 1.7 % )
Rickert et al Cancer 1979;43:1847
COLONOSCOPIC INITIAL EXAM
%
Adenoma 85
Hyperplastic 15
Total 100
National Polyp Study Gastroent 1990; 98:371
Size of Colorectal AdenomaInitial Colonoscopy
Size ( cm ) %
< 0.5 38
0.6-1.0 37
> 1.0 25
Total 100
National Polyp Study Gastroent 1990; 98:371
Colorectal AdenomaIndependent Risk Factors For High Grade Dysplasia
• Size
• Extent of Villous
• Increasing age National Polyp study Gastroent 1990;98:371
Size of Adenoma And Invasive Ca
Size (cm) Invasive Ca (%)
< 0.5 0
0.6-1.5 2
1.6-2.5 19
2.6-3.5 43
> 3.5 76
Nusko G et al. Endoscopy 1997; 20:626
Colorectal Adenoma
Advanced Adenoma
• Adenoma > 1 cm
• Villous component
The Adenoma -Carcinoma Sequence in Cancer of the Colon
Raymond J. Jackman, M.D. and Charles W. Mayo, M.D.,
Rochester, Minnesota
Surg Gynecol Obstet 1951;93:327
Natural History of Small Adenomas
Colorectal Adenomas < 5 mm
30 dimunitive adenomas (26 pt) Follow-up 2 yr
Mean growth 0.6 mm / yr
2 / 30 reached 10 mm
Bersentes K et al. Am J Gastroent 1997 ; 92 : 117
Natural History of Colorectal Adenomas
68 adenomas < 1 cm ( 58 pt ) Follow- up 3 yr
17 ( 25 % ) same size
27 ( 40 % ) grew ---- most rapid = 4mm in 3 yr
24 ( 35% ) shrunk
Hofstad B et al. Gut 1996; 39 : 449
Natural History of An Adenoma1 cm or Larger
N = 226
Mean Follow-up 5 yr (1-27 yr)
%
Disappear 5
No Growth 57
Growth 38 Otchy D et al. Am J Gastro 1996; 91:448
Natural History of An Adenoma
Risk of >1cm adenoma
Year Invasive Ca.(%)
5 2.5
10 8.0
15 24.0 Stryker S et al. Gastroent 1987; 83:1009
Progression of Adenoma and Carcinoma
From clean colon to adenoma 5 yr
From clean colon to carcinoma 10 yr
Winawer SW et al. Cancer 1991; 67:1143
Serrated Adenomatous PolypHistorical Perspectives
Hyperplastic in adenomatous polyp
Goldman H et al. Arch Pathol 1970; 89 : 349
Mixed hyperplastic adenomatous polyp Urbanski SJ et al. Am J Surg Path 1984; 8: 551
Serrated adenoma
Longacre TA, Fenoglio – Preiser CM . Am J Surg Path 1990; 14: 524
Molecular Study of Serrated Adenoma No APC mutation
Kras mutation
DNA microsatellite instability ( MSI – L )
Loss of Chromosome 1 P
Mutation of TGF beta RI I
Genetic = neoplastic polyp
Jass JR DCR 2001; 44: 163
Risk Features of Serrated Adenoma
Size > 1 cm
Location in right colon
Presence of high grade dysplasia
Coincidental adenoma
1 st degree relatives with HGD
1 st degree relatives with CR Ca Jass JR DCR 2001 ; 44 : 163
Colonoscopic Polypectomy
Size of Polyps
Size No. %
0.5 - 0.9 674 26
1.0 - 1.9 1296 50
2.0 – 2.9 311 12
3.0 – 3.9 78 3
4.0 – 6.0 52 2
Unretrieved 181 7
Total 2592 100
Colonoscopic PolypectomyComplications in 2592 Polyps
Problem No.
Bleeding 20 ( resulted in 1 death )
Transmural burn 8 ( conservative treatment )
Perforation 2 ( conservative treatment )
Intra-abdominal abscess 1 ( CT drain )
Snare entrapment 1 ( surgery )
Ensnared bowel wall 1 ( surgery )
Total 33 ( 1.3% )
ADENOMATOUS POLYPS OF COLON AND RECTUM
• Incidence
• Risk factors of an adenoma
• Natural history of an adenoma
• Serrated adenoma
• Colonoscopic polypectomy