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 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 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 Adenoma Initial Colonoscopy Size ( cm ) % < > Total 100 National Polyp Study Gastroent 1990; 98:371

Colorectal Adenoma Independent 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 (%) < > 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 Adenoma 1 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.(%) 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 Polyp Historical 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. % – – – Unretrieved Total

Colonoscopic Polypectomy Complications 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