Positive predictive value for polyps detected at screening CT colonography

Pickhardt, Perry J.; Wise, Steven M.; Kim, David H.

doi:10.1007/s00330-009-1704-z

Cited by 52 publications

(39 citation statements)

References 21 publications

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“…Specificity and PPV were less good, with the latter ranging from 62 to 88%, somewhat lower than the 92-93% reported when CTC is used for asymptomatic screenees [33,34]. The pooled estimate of specificity was 75.4%, although heterogeneity was high.…”

Section: Discussionmentioning

confidence: 77%

Sensitivity and specificity of CT colonography for the detection of colonic neoplasia after positive faecal occult blood testing: systematic review and meta-analysis

et al. 2014

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Sensitivity and specificity of CT colonography for the detection of colonic neoplasia after positive faecal occult blood testing: Systematic review and meta-analysis. European Radiology, 24 (5) 1049 -1058. 10.1007/s00330-014-3106-0 Article Sensitivity and specificity of CTC for the detection of colonic neoplasia after positive fecal occult blood testing: Systematic review and meta-analysis Abstract Objective: CT colonography (CTC) is recommended after positive fecal occult blood testing (FOBt) when colonoscopy is incomplete or infeasible. We aimed to estimate the sensitivity and specificity of CTC for colorectal cancer and adenomatous polyps following positive FOBt via systematic review. Methods:The MEDLINE, EMBASE, AMED and Cochrane Library databases were searched for CTC studies reporting sensitivity and specificity for colorectal cancer and adenomatous polyps. Included subjects had tested FOBt-positive by guaiac or immunochemical methods. Per-patient detection rates were summarized via forest plots. Meta-analysis of sensitivity and specificity was conducted using a bivariate random effects model and the average operating point calculated.Results: Of 538 articles considered, 5 met inclusion criteria, describing results from 622 patients. Research study quality was good. CTC had a high per-patient average sensitivity of 88.8% (95%CI 83.6 to 92.5%) for ≥6mm adenomas or colorectal cancer, with low betweenstudy heterogeneity. Specificity was both more heterogeneous and lower, at an average of 75.4% (95%CI 58.6 to 86.8%). Conclusion:Few studies have investigated CTC in FOBt-positive individuals. CTC is sensitive at a ≥6mm threshold but specificity is lower and variable. Despite the limited data, these results suggest CTC may adequately substitute for colonoscopy when the latter is undesirable.Keywords CT colonography, Colorectal Neoplasms, Screening, Occult blood, Review, Systematic Key points Faecal occult blood testing is the commonest mass-screening test for colorectal cancer.  Few studies specifically evaluate CT colonography after positive faecal occult blood testing.  CTC is approximately 89% sensitive for ≥6mm adenomas/cancer in this setting.  Specificity is lower, at approximately 75%, and more variable.  CT colonography is a good alternative when colonoscopy is undesirable.Abbreviations CAD = computer assisted detection CTC = computed tomographic colonography CRC = colorectal cancer gFOBt = guaiac faecal occult blood test 2 FIT = faecal immunochemical test NPV = negative predictive value PPV = positive predictive value QUADAS-2 = quality assessment of diagnostic accuracy studies, second revision

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Section: Discussionmentioning

confidence: 77%

Sensitivity and specificity of CT colonography for the detection of colonic neoplasia after positive faecal occult blood testing: systematic review and meta-analysis

et al. 2014

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“…This discordant rate is much higher than we observed in our study, where 95% of left-sided lesions were matched. In general, the positive predictive value of CT colonography in our screening program was more than 90% for all polyps 6 mm or larger ( 17 ). This disparity may also help to explain the lower rate of proximal polyps found at optical colonoscopy in our CT colonogaphic cohort with positive results for left-sided lesions.…”

Section: Gastrointestinal Imaging: Is Left-sided Polyp Detection At Cmentioning

confidence: 78%

Left-sided Polyps Detected at Screening CT Colonography: Do We Need Complete Optical Colonoscopy for Further Evaluation?

Pickhardt¹,

Durick²,

Pooler³

et al. 2011

Radiology

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Purpose:To estimate the relative yield of therapeutic fl exible sigmoidoscopy compared with complete optical colonoscopy for isolated left-sided polyps ( Ն 6 mm in diameter) identifi ed at screening computed tomographic (CT) colonography. Materials and Methods:This retrospective institutional review board-approved and HIPAA-compliant study included a review of CT colonographic screening results in 6570 consecutive asymptomatic adults (3551 women, 3019 men; mean age, 56.8 years 6 7.3 [standard deviation]). Of 887 (13.5%) patients with cases positive for nondiminutive polyps ( Ն 6 mm), a subset of 171 patients met the inclusion criteria (a) of having left-sided-only lesions of 6 mm or larger identifi ed at CT colonography (rectum-to-splenic fl exure) and (b) of undergoing subsequent evaluation with complete optical colonoscopy. CT colonography-optical colonoscopy concordance and proximal-versus-distal diagnostic yield at optical colonoscopy were assessed. The 95% confi dence intervals (CIs) were calculated for relevant results. Results:From the study group of 171 patients, a total of 234 leftsided lesions of 6 mm or larger were prospectively reported at CT colonography, of which 222 (94.9%; 95% CI: 91.3%, 97.0%) were confi rmed as true-positive fi ndings at optical colonoscopy. With optical colonoscopy, an additional 17 benign left-sided polyps of 6 mm or larger (13 small, four large) were found in 11 patients, resulting in a total left-sided yield of 239 nondiminutive lesions, including 137 small polyps (6-9 mm) and 102 large lesions ( Ն 10 mm), 160 neoplasms, 82 advanced adenomas, and seven cancers. Evaluation of the colon proximal to the splenic fl exure in this cohort yielded eight small and two large benign polyps in nine patients but no proximal cancers or histologically advanced lesions. Conclusion:For patients with left-sided-only polyps detected at CT colonography, the additional yield of complete optical colonoscopy beyond the expected reach of fl exible sigmoidoscopy is very low and may not justify the added costs, potential risks, and procedural time.q RSNA, 2011

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“…Key categories of colorectal polyp findings at repeat CT colonography screening (eg, C-RADS categories C2-C4, advanced neoplasia, invasive cancer, lesion morphology, lesion location, etc) were compared against summary statistics from earlier programmatic results for initial CT colonography screening as reported in previous publications (5,(20)(21)(22). Fisher exact test and Pearson x 2 test were used, where applicable, to test for differences in categorical variables.…”

Section: Discussionmentioning

confidence: 99%

“…High-grade dysplasia was reported in only one (2.4%) of 42 advanced adenomas. Compared with initial screening, advanced lesions colonography screening (P = .071) (21). The remaining 21 (13.0%) lesions were not seen at subsequent OC, representing either CT colonography false-positive or OC false-negative findings (19).…”

Section: Ct Colonography Technique and Interpretationmentioning

confidence: 95%

“…For CT colonography bowel preparations that utilize only an iodinated oral contrast material-or no contrast material at all-the detection rate for clinically relevant flat lesions is likely reduced, although we are not aware of specific data regarding serrated polyp detection in this setting. Regardless, flat lesions remain a challenge for CT colonography (and for OC) and are associated with lower diagnostic confidence and predictive values relative to polypoid lesions (21,30). Nonetheless, CT colonography and OC are likely complementary in detecting flat lesions (31)(32)(33)(34).…”

Section: Gastrointestinal Imaging: Repeat Ct Colonography After Initimentioning

confidence: 99%

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Colorectal Findings at Repeat CT Colonography Screening after Initial CT Colonography Screening Negative for Polyps Larger than 5 mm

Pickhardt¹,

Pooler²,

Mbah³

et al. 2017

Radiology

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Purpose:To determine the rate and types of polyps detected at repeat computed tomographic (CT) colonography screening after initial negative findings at CT colonography screening. Materials and Methods:Among 5640 negative CT colonography screenings (no polyps  6 mm) performed before 2010 at one medical center, 1429 (25.3%; mean age, 61.4 years; 736 women, 693 men) patients have returned for repeat CT colonography screening (mean interval, 5.7 years 6 0.9; range, 4.5-10.7 years). Positive rates and histologic findings of initial and repeat screening were compared in this HIPAAcompliant, institutional review board-approved study. For all patients with positive findings at repeat CT colonography, the findings were directly compared against the initial CT colonography findings. Fisher exact, Pearson x 2 , and Student t tests were applied as indicated. Results:Repeat CT colonography screening was positive for lesions 6 mm or larger in 173 (12.1%) adults (compared with 14.3% at initial CT colonography screening, P = .29).In the 173 patients, 29.5% (61 of 207) of nondiminutive polyps could be identified as diminutive at the initial CT colonography and 12.6% (26 of 207) were missed. Large polyps, advanced neoplasia (advanced adenomas and cancer), and invasive cancer were seen in 3.8% (55 of 1429), 2.8% (40 of 1429), and 0.14% (two of 1429), respectively, at follow-up, compared with 5.2% (P = .02), 3.2% (P = .52), and 0.45% (P = .17), respectively, at initial screening. Of 42 advanced lesions in 40 follow-up screenings, 33 (78.6%) were right sided and 22 (52.4%) were flat, compared with 45.4% (P , .001) and 11.3% (P , .001), respectively, at initial screening. Large right-sided serrated lesions were confirmed in 20 individuals (1.4%), compared with 0.5% (P , .001) confirmed at initial screening. Conclusion:Positive rates for large polyps at repeat CT colonography screening (3.7%) were lower compared with those at initial screening (5.2%). However, more advanced rightsided lesions were detected at follow-up CT colonography, many of which were flat, serrated lesions. The cumulative findings support both the nonreporting of diminutive lesions and a 5-10-year screening interval.q RSNA, 2016

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Positive predictive value for polyps detected at screening CT colonography

Abstract: The overall per-polyp and per-patient PPV for lesions >or=6 mm was 92% for CTC screening. Increased diagnostic confidence and polypoid (non-flat) morphology correlated with a higher PPV, whereas small versus large polyp size had very little effect.

Cited by 52 publications

References 21 publications

Sensitivity and specificity of CT colonography for the detection of colonic neoplasia after positive faecal occult blood testing: systematic review and meta-analysis

Sensitivity and specificity of CT colonography for the detection of colonic neoplasia after positive faecal occult blood testing: systematic review and meta-analysis

Left-sided Polyps Detected at Screening CT Colonography: Do We Need Complete Optical Colonoscopy for Further Evaluation?

Colorectal Findings at Repeat CT Colonography Screening after Initial CT Colonography Screening Negative for Polyps Larger than 5 mm

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