Prospective Blinded Comparison of Polyp Size on Computed Tomography Colonography and Endoscopic Colonoscopy

Barancin, Courtney; Pickhardt, Perry J.; Kim, David H.; Spier, Bret J.; Lindstrom, Mary J.; Reichelderfer, Mark; Gopal, Deepak V.; Pfau, Patrick R.

doi:10.1016/j.cgh.2011.01.020

Cited by 17 publications

(8 citation statements)

References 16 publications

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“…The maximum linear polyp size was confirmed at CTC using a validated approach that combines 2D and 3D assessment. 18,19 Polyp volume was derived using a semi-automated technique that segments the lesion but requires that the user confirm or appropriately adjust the included voxels by manipulating the region of interest on each individual 2D slice. 14 For pedunculated polyps, the stalk was excluded from measurement.…”

Section: Methodsmentioning

confidence: 99%

Assessment of volumetric growth rates of small colorectal polyps with CT colonography: a longitudinal study of natural history

Pickhardt

Kim

Pooler

et al. 2013

The Lancet Oncology

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127

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Background The natural history of small colorectal polyps is an important area for which major evidence gaps persist. We report the results of a prospective trial assessing the behavior of small (6-9 mm) colorectal polyps through in vivo growth rates at longitudinal CT colonography (CTC) evaluation. Methods In vivo CTC surveillance was performed on 306 small (6-9 mm) polyps initially detected at screening CTC in 243 consenting asymptomatic adults (mean interval, 2.3 years; range, 1-7 years). Volumetric and linear polyp measurements at initial and surveillance CTC were correlated with histologic subgroups. Histology was established in 132 lesions at post-CTC colonoscopy. The trial is registered (ClinicalTrials.gov Identifier: NCT00204867) Findings Applying a polyp volume threshold of ±20% change per year to categorize growth, 22% (68/306) of all polyps progressed, 50% (153/306) were stable, and 28% (85/306) regressed, including apparent resolution in 10% (32/306). 91% (21/23) of proven advanced adenomas progressed, compared with 37% (31/84) of proven non-advanced adenomas, and 8% (15/198) of all other lesions (p<0.0001). Odds ratio for a growing polyp at CTC surveillance to represent an advanced adenoma was 15.6 (95%CI, 7.6-31.7) compared with 6-9 mm polyps detected and removed at initial CTC screening (without surveillance). Mean polyp volume change was +77%/year for proven advanced adenomas (n=23), +16%/year for proven non-advanced adenomas (n=84), and -13%/year for all proven non-neoplastic or unresected polyps (p<0.0001). An absolute polyp volume >180 mm3 at surveillance CTC identified proven advanced neoplasia with a sensitivity of 92% (22/24), specificity of 94% (266/282), PPV of 58% (22/38), and NPV of 99% (266/268). In general, volume changes amplified small or absent linear size changes, as only sixteen 6-9 mm polyps (6%) exceeded 10 mm at follow-up. Interpretation Volumetric growth assessment of small colorectal polyps represents a powerful biomarker for determining clinical importance. Advanced adenomas demonstrate more rapid growth than non-advanced adenomas, whereas most other small polyps remain stable or regress over time. These findings may allow for less invasive surveillance strategies, reserving polypectomy for lesions that demonstrate significant growth. Ongoing research will eventually provide more information regarding the ultimate fate of unresected small polyps without significant growth.

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Section: Methodsmentioning

confidence: 99%

Assessment of volumetric growth rates of small colorectal polyps with CT colonography: a longitudinal study of natural history

Pickhardt

Kim

Pooler

et al. 2013

The Lancet Oncology

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127

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“…Maximal lesion height relative to the surrounding normal mucosa was determined on 2D displays. In general, careful lesion measurement at optical colonoscopy can closely match the CT colonography measurement (28). To assess contrast material coating, both polyp window (width, 2000 HU; length, 0 HU) and soft-tissue window (width, 350 HU; length, 40 HU) settings were used.…”

Section: Methodsmentioning

confidence: 99%

Carpet Lesions Detected at CT Colonography: Clinical, Imaging, and Pathologic Features

Pickhardt¹,

Lam²,

Weiss³

et al. 2014

Radiology

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Purpose To describe carpet lesions (laterally spreading tumors ≥ 3 cm) detected at computed tomographic (CT) colonography, including their clinical, imaging, and pathologic features. Materials and Methods The imaging reports for 9152 consecutive adults under-going initial CT colonography at a tertiary center were reviewed in this HIPAA-compliant, institutional review board–approved retrospective study to identify all potential carpet lesions detected at CT colonography. Carpet lesions were defined as morphologically flat, laterally spreading tumors 3 cm or larger. For those patients with neoplastic carpet lesions, CT colonography studies were analyzed to determine maximal lesion width and height, oral contrast material coating, segmental location, and computer-aided detection (CAD) findings. Demographic data and details of clinical treatment in these patients were reviewed. Results Eighteen carpet lesions in 18 patients (0.2%; mean age, 67.1 years; eight men, 10 women) were identified and were subsequently confirmed at colonoscopy and pathologic examination among 20 potential flat masses (≥3 cm) prospectively identified at CT colonography (there were two nonneoplastic rectal false-positive findings). No additional neoplastic carpet lesions were found in the cohort undergoing colonoscopy after CT colonography and/or surgery (there were no false-negatives). Mean lesion width was 46.5 mm (range, 30–80 mm); mean lesion height was 7.9 mm (range, 4–14 mm). Surface retention of oral contrast material was noted in all 18 cases. All but two lesions were located in the distal rectosigmoid or proximal right colon. At CAD, 17 (94.4%) lesions were detected (mean, 6.2 CAD marks per lesion). Sixteen lesions (88.9%) demonstrated advanced histologic features, including a villous component (n = 11), high-grade dysplasia (n = 4), and invasive cancer (n = 5). Sixteen patients (88.9%) required surgical treatment for complete excision. Conclusion CT colonography can effectively depict carpet lesions. Common features in this series included older patient age, rectal or cecal location, surface coating with oral contrast material, multiple CAD hits, advanced yet typically benign histologic features, and surgical treatment.

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“…Also, polyp size in our database was based on postfixation measurement. Some studies have suggested that formalin fixation leads to “shrinkage” and underestimation of polyp size, 17–19 whereas others have reported that pathology measurements are the most accurate measure of polyp size. 20 If underestimation occurred, it may have led to undersize classification of some advanced polyps.…”

Section: Discussionmentioning

confidence: 99%

Polyps With Advanced Neoplasia Are Smaller in the Right Than in the Left Colon: Implications for Colorectal Cancer Screening

Gupta

Balasubramanian

et al. 2012

Clinical Gastroenterology and Hepatology

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Background & Aims Colonoscopy is consistently associated with reduced left-sided, but not right-sided, colorectal cancer (CRC) incidence and mortality. This might be because polyps with advanced pathology are smaller and more easily missed in the right vs left colon. We explored this postulate by evaluating the relationship among size, location, and histology of polyps from a large nationwide sample. Methods We conducted a cross-sectional study of 233,414 polyps from 142,686 patients (47% women; mean age, 60 years), which were reviewed by Miraca Life Sciences in 2009. We assessed polyp histology, location, and size of largest fragment submitted. We compared size distribution of right vs left polyps with high-grade dysplasia (HGD) or adenocarcinoma as well as any advanced neoplasia. Results The average size of right-sided polyps was smaller than that of left-sided polyps with HGD or adenocarcinoma (8.2 vs 12.4 mm, respectively); the same was true for polyps with advanced neoplasia (7.6 vs 11.1 mm, respectively) (P < .001). Most right-sided polyps with HGD, adenocarcinoma, or any advanced neoplasia were ≤9 mm, whereas most left-sided polyps with these findings were >9 mm. Polyps with advanced pathology were 5-fold more likely to be <6 mm in the right vs left colon: odds ratio, 5.27; 95% confidence interval, 4.06–6.82 for HGD or adenocarcinoma; odds ratio, 4.89; 95% confidence interval, 4.34–5.51 for advanced neoplasia. Conclusions Polyps with features of HGD, adenocarcinoma, or advanced neoplasia were significantly smaller in the right vs left colon. Strategies to prevent right-sided CRC require more accurate detection of small, advanced polyps.

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Prospective Blinded Comparison of Polyp Size on Computed Tomography Colonography and Endoscopic Colonoscopy

Cited by 17 publications

References 16 publications

Assessment of volumetric growth rates of small colorectal polyps with CT colonography: a longitudinal study of natural history

Assessment of volumetric growth rates of small colorectal polyps with CT colonography: a longitudinal study of natural history

Carpet Lesions Detected at CT Colonography: Clinical, Imaging, and Pathologic Features

Polyps With Advanced Neoplasia Are Smaller in the Right Than in the Left Colon: Implications for Colorectal Cancer Screening

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