Sociodemographic Factors and Screening CT Colonography Use Among Medicare Beneficiaries.

BACKGROUND. Approximately one-third of the eligible U.S. population have not undergone guideline-compliant colorectal cancer (CRC) screening. Guidelines recognize various screening strategies to increase adherence. CMS provides coverage for all recommended screening tests except CT colonography (CTC). OBJECTIVE. The purpose of this study was to compare CTC and other CRC screening tests in terms of associations of utilization with income, race and ethnicity, and urbanicity in Medicare fee-for-service beneficiaries. METHODS. This retrospective study used CMS Research Identifiable Files from January 1, 2011, through December 31, 2020. These files contain claims information for 5% of Medicare fee-for-service beneficiaries. Data were extracted for individuals 45-85 years old, and individuals with high CRC risk were excluded. Multivariable logistic regression models were constructed to determine the likelihood of undergoing CRC screening tests (as well as of undergoing diagnostic CTC, a CMS-covered test with similar physical access as screening CTC) as a function of income, race and ethnicity, and urbanicity while controlling for sex, age, Charlson comorbidity index, U.S. census region, screening year, and related conditions and procedures. RESULTS. For 12,273,363 beneficiary years (mean age, 70.5 ± 8.2 [SD] years; 2,436,849 unique beneficiaries: 6,774,837 female beneficiaries, 5,498,526 male beneficiaries), there were 785,103 CRC screenings events, including 645 for screening CTC. Compared with individuals living in communities with per capita income of less than US$25,000, individuals in communities with income of US$100,000 or more had OR for undergoing screening CTC of 5.73, optical colonoscopy (OC) of 1.36, sigmoidoscopy of 1.03, guaiac fecal occult blood test or fecal immunochemical test of 1.50, stool DNA of 1.43, and diagnostic CTC of 2.00. The OR for undergoing screening CTC was 1.00 for Hispanic individuals and 1.08 for non-Hispanic Black individuals compared with non-Hispanic White individuals. Compared with the OR for undergoing screening CTC for residents of metropolitan areas, the OR was 0.51 for residents of micropolitan areas and 0.65 for residents of small or rural areas. CONCLUSION. The association with income was substantially larger for screening CTC than for other CRC screening tests or for diagnostic CTC. CLINICAL IMPACT. Medicare's noncoverage for screening CTC may contribute to lower adherence with CRC screening guidelines for lower-income beneficiaries. Medicare coverage of CTC could reduce income-based disparities for individuals avoiding OC owing to invasiveness, need for anesthesia, or complication risk.

Colon capsule endoscopy following incomplete colonoscopy in routine clinical settings.

BACKGROUND: Colon capsule endoscopy (CCE) was introduced in our department on two indications; following incomplete colonoscopy as an alternative to CT colonography, and in patients with a history of incomplete colonoscopy as an alternative to anesthesia-assisted (AA) colonoscopy. We aimed to compare the quality of CCE, defined by completion rate and polyp detection rate (PDR), with that of CT colonography and AA colonoscopy, respectively. METHODS: Patients referred for CCE from May 2020 until November 2021 were consecutively included in this prospective cohort study. Demographics, indication and CCE outcomes were registered from the electronic patient record. Completion rate and PDR in CCE as an alternative to CT colonography were compared with those of a historical cohort undergoing CT colonography following incomplete colonoscopy. Completion rate and PDR in CCE as an alternative to AA colonoscopy were compared with those of a time true parallel cohort undergoing AA colonoscopy. RESULTS: In 65 patients undergoing CCE, 36 (57%) were referred as an alternative to CT colonography. The completion rate in this group was 44% compared to 96% in CT colonography (p < 0.001). The PDR in complete CCE in this group was 75% in CCE compared to 20% in CT colonography (p < 0.001). The remaining 27 (43%) of the sample were referred for CCE as an alternative to AA colonoscopy. The completion rate in this group was 33% compared to 100% in AA colonoscopy (p < 0.001). The PDR in complete CCE in this group was 78% in CCE compared to 35% in AA colonoscopy (p = 0.013). CONCLUSIONS: The completion rate of CCE following incomplete colonoscopy is inferior to that of CT colonography and AA colonoscopy. The PDR of CCE was high, indicating an acceptable sensitivity in complete investigations, but in our settings the completion rate of CCE on this indication is unacceptably low. CLINICAL TRIAL REGISTRATION: NCT04307901 (ClinicalTrials.gov, March 13, 2020).

Optimal Strategies for Colorectal Cancer Screening.

OPINION STATEMENT: Colorectal cancer (CRC) imposes significant morbidity and mortality, yet it is also largely preventable with evidence-based screening strategies. In May 2021, the US Preventive Services Task Force updated guidance, recommending screening begin at age 45 for average-risk individuals to reduce CRC incidence and mortality in the United States (US). The Task Force recommends screening with one of several screening strategies: high-sensitivity guaiac fecal occult blood test (HSgFOBT), fecal immunochemical test (FIT), multi-target stool DNA (mt-sDNA) test, computed tomographic (CT) colonography (virtual colonoscopy), flexible sigmoidoscopy, flexible sigmoidoscopy with FIT, or traditional colonoscopy. In addition to these recommended options, there are several emerging and novel CRC screening modalities that are not yet approved for first-line screening in average-risk individuals. These include blood-based screening or "liquid biopsy," colon capsule endoscopy, urinary metabolomics, and stool-based microbiome testing for the detection of colorectal polyps and/or CRC. In order to maximize CRC screening uptake in the US, patients and providers should engage in informed decision-making about the benefits and limitations of recommended screening options to determine the most appropriate screening test. Factors to consider include the invasiveness of the test, test performance, screening interval, accessibility, and cost. In addition, health systems should have a programmatic approach to CRC screening, which may include evidence-based strategies such as patient education, provider education, mailed screening outreach, and/or patient navigation, to maximize screening participation.

Conserved serum protein biomarkers associated with growing early colorectal adenomas.

A major challenge for the reduction of colon cancer is to detect patients carrying high-risk premalignant adenomas with minimally invasive testing. As one step, we have addressed the feasibility of detecting protein signals in the serum of patients carrying an adenoma as small as 6-9 mm in maximum linear dimension. Serum protein biomarkers, discovered in two animal models of early colonic adenomagenesis, were studied in patients using quantitative mass-spectrometric assays. One cohort included patients bearing adenomas known to be growing on the basis of longitudinal computed tomographic colonography. The other cohort, screened by optical colonoscopy, included both patients free of adenomas and patients bearing adenomas whose risk status was judged by histopathology. The markers F5, ITIH4, LRG1, and VTN were each elevated both in this patient study and in the studies of the Pirc rat model. The quantitative study in the Pirc rat model had demonstrated that the elevated level of each of these markers is correlated with the number of colonic adenomas. However, the levels of these markers in patients were not significantly correlated with the total adenoma volume. Postpolypectomy blood samples demonstrated that the elevated levels of these four conserved markers persisted after polypectomy. Two additional serum markers rapidly renormalized after polypectomy: growth-associated CRP levels were enhanced only with high-risk adenomas, while PI16 levels, not associated with growth, were reduced regardless of risk status. We discuss biological hypotheses to account for these observations, and ways for these signals to contribute to the prevention of colon cancer.

Effect of dose splitting of a low-volume bowel preparation macrogol-based solution on CT colonography tagging quality.

PURPOSE: To compare examination quality and acceptability of three different low-volume bowel preparation regimens differing in scheduling of the oral administration of a Macrogol-based solution, in patients undergoing computed tomographic colonography (CTC). The secondary aim was to compare CTC quality according to anatomical and patient variables (dolichocolon, colonic diverticulosis, functional and secondary constipation). METHODS: One-hundred-eighty patients were randomized into one of three regimens where PEG was administered, respectively: in a single dose the day prior to (A), or in a fractionated dose 2 (B) and 3 days (C) before the examination. Two experienced radiologists evaluated fecal tagging (FT) density and homogeneity both qualitatively and quantitatively by assessing mean segment density (MSD) and relative standard deviation (RSD). Tolerance to the regimens and patient variables were also recorded. RESULTS: Compared to B and C, regimen A showed a lower percentage of segments with inadequate FT and a significantly higher median FT density and/or homogeneity scores as well as significantly higher MSD values in some colonic segments. No statistically significant differences were found in tolerance of the preparations. A higher number of inadequate segments were observed in patients with dolichocolon (p < 0.01) and secondary constipation (p < 0.01). Interobserver agreement was high for the assessment of both FT density (k = 0.887) and homogeneity (k = 0.852). CONCLUSION: The best examination quality was obtained when PEG was administered the day before CTC in a single session. The presence of dolichocolon and secondary constipation represent a risk factor for the presence of inadequately tagged colonic segments.

Implications of colonic and extra-colonic findings on CT colonography in FIT positive patients in the Dutch bowel cancer screening program.

OBJECTIVES: In the Dutch National colorectal cancer (CRC) screening program, patients with a positive faecal immunochemical test (FIT) are referred for a colonoscopy. In a small proportion, because of contraindications, a computed tomographic colonography (CTC) is performed to rule out advanced neoplasia. The aim of our study is to evaluate the intra- and extra-colonic yield of CTC and its clinical implications. MATERIALS AND METHODS: In this retrospective cohort study, all FIT positive patients who underwent primary (instead of colonoscopy) or secondary CTC (after incomplete colonoscopy) between January 2014 and January 2018 were included. Relevant intra-colonic lesions on CTC were defined as lesions suspected for CRC or >10 mm. Relevant extra-colonic findings were defined as E3 and E4 using the E-RADS classification. RESULTS: Of the 268 included patients, 66 (24.6%) were suspected to have CRC or 10 mm + lesion on CTC and 56 of them (84.8%) underwent an additional endoscopy. Another 20 patients with <10 mm lesions on CTC underwent additional endoscopy. Overall, 76/268 patients (28.4%) underwent confirmatory endoscopy of which 50 (18.7%) had histologic confirmed advanced neoplasia; 4.9% had CRC and 13.8% advanced adenoma. New relevant extra-colonic findings were detected in 13.8%. CONCLUSIONS: In the Dutch National CRC screening program, a CTC was followed by an endoscopic procedure in more than a quarter of patients, resulting in a significant number of advanced neoplasia. Overall, one out of seven CTCs showed new relevant extra-colonic findings which may lead to further diagnostic/therapeutic work-up. Our results can be important for the informed consent procedure.

Preoperative T staging of advanced colorectal cancer by computed tomography colonography.

PURPOSE: Accurate preoperative T staging is important when determining the treatment strategy for advanced colorectal cancer. We have previously reported the usefulness of preoperative T staging based on the spatial relationship of tumors and "bordering vessels" by computed tomography colonography (CTC) with multiplanar reconstruction (MPR). The aims of this study were to evaluate the external validity of this method and to determine whether there is a difference in the accuracy of T staging between the mesenteric and antimesenteric sides. METHODS: The study subjects were 110 patients with colorectal cancer who underwent preoperative CTC and surgical resection from June 2016 to March 2018. Preoperative T stage was determined by CTC based on the relationship between the tumor and the bordering vessels and compared with the pathological T stage. The influence of tumor location, namely, whether the tumor was on the antimesenteric or mesenteric side, on preoperative T staging was assessed in 78 patients with colorectal cancer. RESULTS: Sensitivity, specificity, accuracy, positive, and negative predictive values were respectively, 65%, 91%, 83%, 76%, and 85% for T2 (n = 34); 76%, 82%, 81%, 50%, and 94% for T3 (n = 23); and 77%, 93%, 87%, 86%, and 88% for T4a disease (n = 39). Overall right answer rate was 83.3% (15/18) for the mesenteric side and 65% (39/60) for the antimesenteric side (n = 0.14). CONCLUSION: Diagnostic criteria based on the bordering vessels seen on CTC images with MPR are useful for T staging of colorectal cancer. However, the accuracy differs between the antimesenteric and mesenteric sides.

Colon capsule endoscopy versus CT colonography in FIT-positive colorectal cancer screening subjects: a prospective randomised trial-the VICOCA study.

BACKGROUND: Colon capsule endoscopy (CCE) and CT colonography (CTC) are minimally invasive techniques for colorectal cancer (CRC) screening. Our objective is to compare CCE and CTC for the identification of patients with colorectal neoplasia among participants in a CRC screening programme with positive faecal immunochemical test (FIT). Primary outcome was to compare the performance of CCE and CTC in detecting patients with neoplastic lesions. METHODS: The VICOCA study is a prospective, single-centre, randomised trial conducted from March 2014 to May 2016; 662 individuals were invited and 349 were randomised to CCE or CTC before colonoscopy. Endoscopists were blinded to the results of CCE and CTC. RESULTS: Three hundred forty-nine individuals were included: 173 in the CCE group and 176 in the CTC group. Two hundred ninety individuals agreed to participate: 147 in the CCE group and 143 in the CTC group. In the intention-to-screen analysis, sensitivity, specificity and positive and negative predictive values for the identification of individuals with colorectal neoplasia were 98.1%, 76.6%, 93.7% and 92.0% in the CCE group and 64.9%, 95.7%, 96.8% and 57.7% in the CTC group. In terms of detecting significant neoplastic lesions, the sensitivity of CCE and CTC was 96.1% and 79.3%, respectively. Detection rate for advanced colorectal neoplasm was higher in the CCE group than in the CTC group (100% and 93.1%, respectively; RR = 1.07; p = 0.08). Both CCE and CTC identified all patients with cancer. CCE detected more patients with any lesion than CTC (98.6% and 81.0%, respectively; RR = 1.22; p = 0.002). CONCLUSION: Although both techniques seem to be similar in detecting patients with advanced colorectal neoplasms, CCE is more sensitive for the detection of any neoplastic lesion. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02081742 . Registered: September 16, 2013.

Traditional Serrated Adenomas on CT Colonography: International Multicenter Experience With This Rare Colorectal Neoplasm.

OBJECTIVE. Serrated polyps include hyperplastic polyps, sessile serrated polyps, and traditional serrated adenomas (TSAs). Hyperplastic polyps and sessile serrated polyps account for approximately 99% of all serrated lesions; TSAs are rare. However, both sessile serrated polyps and TSAs are now recognized as precursor lesions to carcinogenesis, representing approximately one-fourth of all sporadic colorectal cancers. We report what is, to our knowledge, the first series describing the characteristics of CTAs on CT colonography (CTC). MATERIALS AND METHODS. An international, multicenter, retrospective review of CT colonography-detected TSAs diagnosed between 2008 and 2018 was conducted. Data collected included patient demographics and data from CTC, optical colonoscopy, and pathologic analysis. RESULTS. A total of 67 proven TSAs in 58 patients (mean age, 67 years) were identified. The majority (66%) were located in the distal colon (descending colon, sigmoid colon, and rectum), and their mean size was 19 mm (range, 3-80 mm). Small (< 10 mm) TSAs typically had a simple sessile or pedunculated morphologic appearance, whereas large (≥ 10 mm) TSAs tended to be more lobulated and irregular, pedunculated, or carpetlike. The majority (88%) showed at least some contrast medium surface coating. CONCLUSION. We report what we believe to be the first multicenter experience describing the characteristics of TSAs on CTC. Unlike sessile serrated lesions, TSAs are more often left-sided and tend to be more lobulated and irregular. However, like sessile serrated polyps, most TSAs show contrast medium surface coating. Detection of these rare lesions on CTC is important, given their malignant potential.

New horizons in iron deficiency anaemia in older adults.

Iron deficiency anaemia (IDA) is common in older adults and associated with a range of adverse outcomes. Differentiating iron deficiency from other causes of anaemia is important to ensure appropriate investigations and treatment. It is possible to make the diagnosis reliably using simple blood tests. Clinical evaluation and assessment are required to help determine the underlying cause and to initiate appropriate investigations. IDA in men and post-menopausal females is most commonly due to occult gastrointestinal blood loss until proven otherwise, although there is a spectrum of underlying causative pathologies. Investigation decisions should take account of the wishes of the patient and their competing comorbidities, individualising the approach. Management involves supplementation using oral or intravenous (IV) iron then consideration of treatment of the underlying cause of deficiency. Future research areas are outlined including the role of Hepcidin and serum soluble transferrin receptor measurement, quantitative faecal immunochemical testing, alternative dosing regimens and the potential role of IV iron preparations.

Pearls and Pitfalls of Interpretation in CT Colonography.

The accuracy of computed tomography (CT) colonography (CTC) requires that the radiologist be well trained in the recognition of pitfalls of interpretation. In order to achieve a high sensitivity and specificity, the interpreting radiologist must be well versed in the causes of both false-positive and false-negative results. In this article, we review the common and uncommon pitfalls of interpretation in CTC.

Improving Image Correlation and Differentiation of 3D Endoluminal Lesions in the Air Spaces Using a Novel Target Gray Level Mapping Technique: A Preliminary Study of Its Application to Computed Tomographic Colonography and Comparison with Traditional Surface Rendering Method.

Purpose: To improve the three dimensional (3D) and two dimensional (2D) image correlation and differentiation of 3D endoluminal lesions in the traditional surface rendering (SR) computed tomographic endoscopy (CTE), a target gray level mapping (TGM) technique is developed and applied to computed tomographic colonography (CTC) in this study. Methods: A study of sixty-two various endoluminal lesions from thirty patients (13 males, 17 females; age range 31-90 years) was approved by our institutional review board and evaluated retrospectively. The endoluminal lesions were segmented using gray level threshold. The marching cubes algorithm was used to detect isosurfaces in the segmented volumetric data sets. TGM allows users to interactively apply grey level mapping (GM) to region of interest (ROI) in the 3D CTC. Radiologists conducted the clinical evaluation and the resulting data were analyzed. Results: TGM and GM are significantly superior to SR in terms of surface texture, 3D shape, the confidence of 3D to 2D, 2D to 3D image correlation, and clinical classification of endoluminal lesions (P < 0.01). The specificity and diagnostic accuracy of GM and TGM methods are significantly better than those of SR (P < 0.01). Moreover, TGM performs better than GM (specificity: 75.0-85.7% vs. 53.6-64.3%; accuracy: 88.7-93.5% vs. 77.4-83.9%). TGM is a preferable display mode for further localization and differentiation of a lesion in CTC navigation. Conclusions: Compared with only the spatial shape information in traditional SR of CTC images, the 3D shapes and gray level information of endoluminal lesions can be provided by TGM simultaneously. 3D to 2D image correlations are also increased and facilitated at the same time. TGM is less affected by adjacent colon surfaces than GM. TGM serves as a better way to improve the image correlation and differentiation of endoluminal lesions.

World Endoscopy Organization Consensus Statements on Post-Colonoscopy and Post-Imaging Colorectal Cancer.

BACKGROUND & AIMS: Colonoscopy examination does not always detect colorectal cancer (CRC)- some patients develop CRC after negative findings from an examination. When this occurs before the next recommended examination, it is called interval cancer. From a colonoscopy quality assurance perspective, that term is too restrictive, so the term post-colonoscopy colorectal cancer (PCCRC) was created in 2010. However, PCCRC definitions and methods for calculating rates vary among studies, making it impossible to compare results. We aimed to standardize the terminology, identification, analysis, and reporting of PCCRCs and CRCs detected after other whole-colon imaging evaluations (post-imaging colorectal cancers [PICRCs]). METHODS: A 20-member international team of gastroenterologists, pathologists, and epidemiologists; a radiologist; and a non-medical professional met to formulate a series of recommendations, standardize definitions and categories (to align with interval cancer terminology), develop an algorithm to determine most-plausible etiologies, and develop standardized methodology to calculate rates of PCCRC and PICRC. The team followed the Appraisal of Guidelines for Research and Evaluation II tool. A literature review provided 401 articles to support proposed statements; evidence was rated using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. The statements were voted on anonymously by team members, using a modified Delphi approach. RESULTS: The team produced 21 statements that provide comprehensive guidance on PCCRCs and PICRCs. The statements present standardized definitions and terms, as well as methods for qualitative review, determination of etiology, calculation of PCCRC rates, and non-colonoscopic imaging of the colon. CONCLUSIONS: A 20-member international team has provided standardized methods for analysis of etiologies of PCCRCs and PICRCs and defines its use as a quality indicator. The team provides recommendations for clinicians, organizations, researchers, policy makers, and patients.

Computed Tomography Colonography vs Colonoscopy for Colorectal Cancer Surveillance After Surgery.

BACKGROUND & AIMS: Recommendations for surveillance after curative surgery for colorectal cancer (CRC) include a 1-year post-resection abdominal-pelvic computed tomography (CT) scan and optical colonoscopy (OC). CT colonography (CTC), when used in CRC screening, effectively identifies colorectal polyps ≥10 mm and cancers. We performed a prospective study to determine whether CTC, concurrent with CT, could substitute for OC in CRC surveillance. METHODS: Our study enrolled 231 patients with resected stage 0-III CRC, identified at 5 tertiary care academic centers. Approximately 1 year after surgery, participants underwent outpatient CTC plus CT, followed by same-day OC. CTC results were revealed after endoscopic visualization of sequential colonic segments, which were re-examined for discordant findings. The primary outcome was performance of CTC in the detection of colorectal adenomas and cancers using endoscopy as the reference standard. RESULTS: Of the 231 participants, 116 (50.2%) had polyps of any size or histology identified by OC, and 15.6% had conventional adenomas and/or serrated polyps ≥6 mm. No intra-luminal cancers were detected. CTC detected patients with polyps of ≥6 mm with 44.0% sensitivity (95% CI, 30.2-57.8) and 93.4% specificity (95% CI, 89.7-97.0). CTC detected polyps ≥10 mm with 76.9% sensitivity (95% CI, 54.0-99.8) and 89.0% specificity (95% CI, 84.8-93.1). Similar values were found when only adenomatous polyps were considered. The negative predictive value of CTC for adenomas ≥6 mm was 90.7% (95% CI, 86.7-94.5) and for adenomas ≥10 mm the negative predictive value was 98.6% (95% CI, 97.0-100). CONCLUSIONS: In a CRC surveillance population 1 year following resection, CTC was inferior to OC for detecting patients with polyps ≥6 mm. Clinical Trials.gov Registration Number: NCT02143115.

Post-operative colorectal cancer surveillance: preference for optical colonoscopy over computerized tomographic colonography.

PURPOSE: Post-operative surveillance strategies for colorectal cancer (CRC) include periodic optical colonoscopy (OC) and abdominal-pelvic CT scan. Adherence with these recommendations is limited. For CRC screening, CT colonography (CTC) identifies larger adenomas and cancers nearly as well as OC. Most screening studies demonstrate that patients prefer CTC. However, CTC has never been compared to OC in the post-operative surveillance setting. METHODS: We hypothesized that CTC might represent an attractive substitute for the standard OC/CT scan combination. Here, 223 patients underwent CTC followed by same day OC 1 year after curative CRC resection. RESULTS: Of the 144/223 (64.6%) participants with a preference, 65.9% (95/144) preferred OC. This preference was more pronounced in women and in patients with polyps detected. No additional patient level factors significantly altered this primary result. CONCLUSIONS: In contrast to CRC screening, this first study in CRC post-operative surveillance patients demonstrates a preference for OC. Assuming patient preference is an important determinant, introduction of CTC as a method to increase patient adherence with CRC surveillance is unlikely to be effective. TRIAL REGISTRATION: Clinical Trials.gov registration number: NCT02143115.

Patients' experience of screening CT colonography with reduced and full bowel preparation in a randomised trial.

OBJECTIVES: To assess patients' experience of bowel preparation and procedure for screening CT colonography with reduced (r-CTC) and full cathartic preparation (f-CTC) that showed similar detection rate for advanced neoplasia in a randomised trial. METHODS: Six hundred seventy-four subjects undergoing r-CTC and 612 undergoing f-CTC in the SAVE trial were asked to complete two pre-examination questionnaires-(1) Life Orientation Test - Revised (LOT-R) assessing optimism and (2) bowel preparation questionnaire-and a post-examination questionnaire evaluating overall experience of CTC screening test. Items were analysed with chi-square and t test separately and pooled. RESULTS: LOT-R was completed by 529 (78%) of r-CTC and by 462 (75%) of f-CTC participants and bowel preparation questionnaire by 531 (79%) subjects in the r-CTC group and by 465 (76%) in the f-CTC group. Post-examination questionnaire was completed by 525 (78%) subjects in the r-CTC group and by 453 (74%) in the f-CTC group. LOT-R average score was not different between r-CTC (14.27 ± 3.66) and f-CTC (14.54 ± 3.35) (p = 0.22). In bowel preparation questionnaire, 88% of r-CTC subjects reported no preparation-related symptoms as compared to 70% of f-CTC subjects (p < 0.001). No interference of bowel preparation with daily activities was reported in 80% of subjects in the r-CTC group as compared to 53% of subjects in the f-CTC group (p < 0.001). In post-examination questionnaire, average scores for discomfort of the procedure were not significantly different between r-CTC (3.53 ± 0.04) and f-CTC (3.59 ± 0.04) groups (p = 0.84). CONCLUSIONS: Reduced bowel preparation is better tolerated than full preparation for screening CT colonography. KEY POINTS: • Reduced bowel preparation is better tolerated than full preparation for screening CT colonography. • Procedure-related discomfort of screening CT colonography is not influenced by bowel preparation. • Males tolerate bowel preparation and CT colonography screening procedure better than females.

Volumetric growth rates of sessile serrated adenomas/polyps observed in situ at longitudinal CT colonography.

OBJECTIVE: Sessile serrated adenomas/polyps (SSA/Ps) are now recognized as potential cancer precursors, but little is known about their natural history. We assessed the in vivo growth rates of histologically proven SSA/Ps at longitudinal CT colonography (CTC) and compared results with non-advanced tubular adenomas (TAs). METHODS: We identified a cohort of 53 patients (mean age, 54.8 ± 5.5 years; M:F, 26:27) from one center with a total of 58 SSA/Ps followed longitudinally at CTC (mean follow-up interval, 5.3 ± 1.9 years). Initial and final size measurements were determined using dedicated CTC software. Findings were compared with 141 non-advanced TAs followed at CTC (mean, 4.1 ± 2.3 years) in 113 patients (mean age, 56.8 ± 6.9 years). RESULTS: SSA/Ps were more often flat (62% [36/58] vs. 14% [20/141], p < 0.0001) and right-sided (98% [57/58] vs. 46% [65/141], p < 0.0001) compared with TAs. Initial average diameter was greater for SSA/Ps (9.3 mm vs. 6.3 mm; p < 0.0001). Mean annual volumetric growth was + 12.7%/year for SSA/Ps vs. + 36.4%/year for TAs (p = 0.028). Using a previously defined threshold of + 20% increase in volume/year to define progression, 22% (13/58) of SSA/Ps and 41% (58/141) of TAs progressed (p = 0.014). None of the SSA/Ps had dysplasia or invasive cancer at histopathology. CONCLUSIONS: Sessile serrated adenoma/polyps demonstrate slower growth compared with conventional non-advanced tubular adenomas, despite larger initial linear size. This less aggressive behavior may help explain the more advanced patient age for serrated pathway cancers. Furthermore, these findings could help inform future colonoscopic surveillance strategies, as current guidelines are largely restricted to expert opinion related to the absence of natural history data. KEY POINTS: • Sessile serrated adenoma/polyps (SSA/Ps) tend to be flat, right-sided, and demonstrate slower growth compared with conventional non-advanced tubular adenomas. • This less aggressive behavior of SSA/Ps may help explain the more advanced patient age for serrated pathway cancers.

Positive Predictive Value for Colorectal Lesions at CT Colonography: Analysis of Factors Impacting Results in a Large Screening Cohort.

OBJECTIVE. The purpose of this study is to evaluate factors affecting the positive predictive value (PPV) for detecting colorectal lesions at CT colonography (CTC), using optical colonoscopy (OC) as the reference standard for concordance. MATERIALS AND METHODS. Consecutive CTC studies from a single screening program interpreted as positive for at least one detected colorectal lesion 6 mm or larger and sent for subsequent OC were analyzed according to per-polyp and per-patient results. Univariable and multivariable analysis of multiple input factors was performed. RESULTS. Of 1650 studies (median patient age, 59.7 years; 877 men and 773 women) with 2688 total CTC-detected lesions 6 mm or larger, the overall PPVs were 88.8% (2386/2688) by polyp and 90.8% (1499/1650) by patient. The by-polyp PPV was significantly higher for polypoid (91.2%; 1793/1965) versus flat or nonpolypoid (79.4%; 459/578) lesions (p < 0.0001). Overall per-patient PPVs were 72.3% (1193/1650) for any neoplasia 6 mm or larger and 38.8% (641/1650) for advanced neoplasia. PPVs for advanced neoplasia increased by CTC Reporting and Data System category: 5.8% (45/781) for C2, 67.1% (511/762) for C3, and 79.4% (85/107) for C4. PPVs for cancer also increased by CTC Reporting and Data System category: 0% (0/781) for C2, 2.2% (17/762) for C3, and 52.3% (56/107) for C4. On multivariable regression analysis, polyp morphologic type (flat vs polypoid) and diagnostic confidence were the strongest predictors of CTC-OC concordance. CTC PPV results are somewhat underestimated because 28.8% (87/302) of CTC-OC-discordant results were categorized as likely OC false-negatives at consensus review. CONCLUSION. Concordance between CTC and OC is high for relevant colorectal polyps and masses. Unlike stool-based tests that provide only a binary positive or negative result, CTC can specify the nature of the positive findings, resulting in much greater specificity and risk stratification for patient management decisions.

CT Colonography in Preoperative Staging of Colon Cancer: Evaluation of FOxTROT Inclusion Criteria for Neoadjuvant Therapy.

OBJECTIVE: The purpose of the present study is to evaluate the diagnostic performance of and interreader agreement for CT colonography (CTC) in the local staging of colon cancer, with emphasis given to the FOxTROT (Fluoropyrimidine, Oxaliplatin, and Targeted-Receptor pre-Operative Therapy [Panitumumab]) trial inclusion criteria, which propose a new tailored treatment paradigm for colon cancer that uses neoadjuvant therapy for patients with a high-risk of locoregional disease as determined by imaging. MATERIALS AND METHODS: This biinstitutional retrospective study involved 89 patients (with 93 tumors) who had colon cancer and underwent presurgical CTC. Two radiologists reviewed the CTC studies for local staging, including measurement of the tumor beyond the muscularis propria on a true orthogonal plane. Histopathologic findings for surgical colectomy specimens served as the reference standard for local pathologic staging. The sensitivity, specificity, positive predictive value, and negative predictive value for local determination of the T category, N category, and extramural vascular invasion (EMVI) were calculated separately for each reader. High-risk T category tumors were the same as those as used in the FOxTROT trial. Interreader agreement was assessed using the kappa statistic. RESULTS: Thirty-five of 93 tumors (37.6%) were histologically classified as high-risk tumors (T3c, T3d, or T4 tumors). The interreader agreement was substantial (κ = 0.68) for classifying high-risk tumors with the use of CTC, moderate for differentiating N0 from N1 and N2 (κ = 0.44), and slight for detecting EMVI (κ = 0.15). The diagnostic statistics for CTC for the two readers were as follows: for detection of high-risk tumors, sensitivity was 65.7% and 82.9%, and specificity was 81.0% and 87.9%; for detection of N category-positive disease, sensitivity was 50.9% and 69.8%, and specificity was 50.0% and 72.5%; and for detection of EMVI, sensitivity was 18.2% and 66.7%, and specificity was 60.0% and 91.7%. CONCLUSION: The present study shows that CTC might be a feasible imaging modality for preoperative local staging of higher-risk colon cancers for which neoadjuvant chemotherapy is more suitable on the basis of the FOxTROT trial criteria. However, further studies are required to allow a better generalization of our results.

Preoperative T staging of colon cancer using CT colonography with multiplanar reconstruction: new diagnostic criteria based on "bordering vessels".

PURPOSE: Preoperative T staging of colon cancer, in particular, for distinguishing T3 from T2 and T4, has been a challenge. The aim of this study was to evaluate newly developed criteria for preoperative T staging of colorectal cancer using computed tomography colonography (CTC) with multiplanar reconstruction (MPR), based on the spatial relationship of tumors and "bordering vessels," that is, marginal vessels that are detectable by multi-detector row CT with MPR. METHODS: A total of 172 patients with colon and upper rectal cancer who underwent preoperative CTC and surgery between August 2011 and September 2013 were included. Preoperative T staging using the new criteria was performed prospectively and compared with pathologic results. RESULTS: Sensitivity, specificity, and accuracy of T staging by CTC using the new criteria were 63%, 80%, and 77% for T2 (n = 30); 72%, 94%, and 81% for T3 (n = 95); and 79%, 99%, and 97% for T4a (n = 14), respectively. Positive predictive value for T3 was 93%, indicating that a T3 diagnosis by CTC is precise. In addition, negative predictive value for pathological T4a was 98%, indicating that a "not T4a" diagnosis by CTC is also precise. CONCLUSIONS: Our newly developed criteria are useful for preoperative T staging, particularly for distinguishing T3 from T2 and T4.