Missed adenomas during colonoscopic surveillance in individuals with Lynch Syndrome (hereditary nonpolyposis colorectal cancer).
OBJECTIVE
Lynch syndrome (also known as hereditary nonpolyposis colon cancer) is associated with an increased risk for colorectal cancer, which can arise despite frequent colonoscopic exams. We evaluated the adenoma miss rate of conventional colonoscopy in patients with Lynch syndrome, and compared the sensitivity of chromoendoscopy versus intensive inspection for detecting polyps missed by conventional colonoscopy.


METHODS
Fifty-four subjects with Lynch syndrome underwent tandem colonoscopies at four centers of the Great Lakes-New England Clinical Epidemiology and Validation Center of the Early Detection Research Network. All participants first had a conventional colonoscopy with removal of all visualized polyps. The second endoscopy was randomly assigned as either pancolonic indigo carmine chromoendoscopy or standard colonoscopy with intensive inspection lasting >20 minutes. Size, histology, and number of polyps detected on each exam were recorded.


RESULTS
After undergoing standard colonoscopy, 28 individuals were randomized to a second exam with chromoendoscopy and 26 underwent intensive inspection. The mean interval since last colonoscopy was 17.5 months. Seventeen polyps (10 adenomas and 7 hyperplastic polyps) were identified on the first standard colonoscopies. Twenty-three additional polyps (12 adenomas and 11 hyperplastic polyps) were found on the second exams, yielding an adenoma miss rate of 55%. Fifteen polyps (5 adenomas and 10 hyperplastic polyps) were found in subjects who had chromoendoscopy and 8 polyps (7 adenomas and 1 hyperplastic polyp) in those who had intensive inspection. Chromoendoscopy was associated with more normal tissue biopsies (11 versus 5) and longer procedure times compared with intensive inspection (29.8 +/- 9.5 versus 25.3 +/- 5.8 minutes; P = 0.04). Controlling for age, number of previous colonoscopies, procedure time, and prior colonic resection, chromoendoscopy detected more polyps (P = 0.04), but adenoma detection was not significantly different compared with intensive inspection (P = 0.27).


CONCLUSIONS
Small adenomas are frequently missed in patients with Lynch syndrome. Although chromoendoscopy did not detect more missed adenomas than intensive inspection in this pilot study, larger trials are needed to determine optimal surveillance techniques in this high-risk population.
Stoffel
Elena M
EM
Division of Gastroenterology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. estoffel@partners.org
Turgeon
D Kim
DK
Stockwell
David H
DH
Zhao
Lili
L
Normolle
Daniel P
DP
Tuck
Missy K
MK
Bresalier
Robert S
RS
Marcon
Norman E
NE
Baron
John A
JA
Ruffin
Mack T
MT
Brenner
Dean E
DE
Syngal
Sapna
S
D000236:Adenoma / Q000175:diagnosis* / Q000209:etiology; D000328:Adult; D003110:Colonic Neoplasms / Q000175:diagnosis* / Q000209:etiology; D003111:Colonic Polyps / Q000175:diagnosis; D003113:Colonoscopy / Q000379:methods*; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000150:complications* / Q000175:diagnosis; D003937:Diagnosis, Differential; D055088:Early Detection of Cancer; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000175:diagnosis; D011159:Population Surveillance / Q000379:methods*