Colorectal Adenomas Santhat Nivatvongs MD Mayo Clinic Rochester Minnesota U. S.A.
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Transcript of Colorectal Adenomas Santhat Nivatvongs MD Mayo Clinic Rochester Minnesota U. S.A.
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