Evolution of Screen-Detected Small (6-9 mm) Polyps After a 3-Year Surveillance Interval: Assessment of Growth With CT Colonography Compared With Histopathology.
OBJECTIVE
Volumetric growth assessment has been proposed for predicting advanced histology at surveillance computed tomography (CT) colonography (CTC). We examined whether is it possible to predict which small (6-9 mm) polyps are likely to become advanced adenomas at surveillance by assessing volumetric growth.


METHODS
In an invitational population-based CTC screening trial, 93 participants were diagnosed with one or two 6-9 mm polyps as the largest lesion(s). They were offered a 3-year surveillance CTC. Participants in whom surveillance CTC showed lesion(s) of ≥6 mm were offered colonoscopy. Volumetric measurements were performed on index and surveillance CTC, and polyps were classified into growth categories according to ±30% volumetric change (>30% growth as progression, 30% growth to 30% decrease as stable, and >30% decrease as regression). Polyp growth was related to histopathology.


RESULTS
Between July 2012 and May 2014, 70 patients underwent surveillance CTC after a mean surveillance interval of 3.3 years (s.d. 0.3; range 3.0-4.6 years). In all, 33 (35%) of 95 polyps progressed, 36 (38%) remained stable, and 26 (27%) regressed, including an apparent resolution in 13 (14%) polyps. In 68 (83%) of the 82 polyps at surveillance, histopathology was obtained; 15 (47%) of 32 progressing polyps were advanced adenomas, 6 (21%) of 28 stable polyps, and none of the regressing polyps.


CONCLUSIONS
The majority of 6-9 mm polyps will not progress to advanced neoplasia within 3 years. Those that do progress to advanced status can in particular be found among the lesions that increased in size on surveillance CTC.
Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.|Department of Radiology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
Charlotte J
CJ
Tutein Nolthenius
Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Thierry N
TN
Boellaard
Department of Radiology, University Medical Center, Utrecht, The Netherlands.
Margriet C
MC
de Haan
Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
C Yung
CY
Nio
Department of Radiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
Maarten G J
MG
Thomeer
Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Shandra
S
Bipat
Department of Radiology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
Alexander D
AD
Montauban van Swijndregt
Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Marc J
MJ
van de Vijver
Department of Pathology, Erasmus University Medical Center, Rotterdam, The Netherlands.
Katharina
K
Biermann
Department of Gastroenterology and Hepatology, Erasmus University Medical Center, Rotterdam, The Netherlands.|Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands.
Ernst J
EJ
Kuipers
Department of Gastroenterology and Hepatology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Evelien
E
Dekker
Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Jaap
J
Stoker
D000236:Adenoma / Q000000981:diagnostic imaging / Q000473:pathology*; D000328:Adult; D000368:Aged; D002471:Cell Transformation, Neoplastic; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D003111:Colonic Polyps / Q000000981:diagnostic imaging / Q000473:pathology*; D023881:Colonography, Computed Tomographic; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods*; D013997:Time Factors