BACKGROUND: Since 2003, a decline in the age-standardized incidence rates of colorectal cancer (CRC) has been observed in Germany. Nonetheless, one in eight cancer cases still affects the colon or rectum. The prognosis has improved, with the relative 5‑year survival rate for CRC being approximately 65%.
METHODS: This positive trend is probably a result of preventive measures introduced over the last 20 years. This could be further improved, however, as CRC can not only be detected early but in almost all cases also prevented through the identification of benign precursors. Less than half of all eligible individuals participate in screening via colonoscopy. This implies that further, possibly even imaging, screening test methods should be explored and offered. Studies have reported that virtual colonography techniques have a comparable accuracy to endoscopy of about 90% for polyp sizes larger than 5 mm. The data for computed tomography (CT) is more extensive than for magnetic resonance imaging (MRI).
CONCLUSIONS: Significant challenges are posed however by the fact that in Germany CT colonography (CTC) is not considered a viable screening option due to radiation protection concerns, and MRI screening is not an established screening method. Radiologists should be familiar with classification using the CT Colonography Reporting and Data System (C-RADS), which uses criteria such as CT density, morphology, size, and location for classification. C‑RADS classification follows the categories: C0 (inadequate study), C1 (normal), C2a (indeterminate), C2b (benign), C3 (suspicious), and C4 (malignant), as well as extracolonic categories E1/2 (no clinically significant findings), E3 (likely insignificant findings), and E4 (likely significant findings).
UNASSIGNED: HINTERGRUND: Seit 2003 ist in Deutschland ein Rückgang der altersstandardisierten Erkrankungsraten des kolorektalen Karzinoms (CRC) zu beobachten. Trotzdem betrifft etwa jede achte Krebserkrankung das Kolon oder Rektum. Die Prognose hat sich verbessert, die relative 5‑Jahres-Überlebensrate mit Darmkrebs liegt um 65 %.
METHODS: Die positive Entwicklung ist vermutlich auch Folge der Vorsorgemaßnahmen der letzten 20 Jahre. Diese könnten weiter verbessert werden, da das CRC nicht nur früh entdeckt, sondern in fast allen Fällen durch die Aufdeckung noch harmloser Vorstufen vermieden werden könnte. Neben der Koloskopie sollten weitere, eventuell auch bildgebende Testverfahren erprobt und angeboten werden, die eine geringere Schwelle darstellen. Die virtuellen Verfahren der Kolographie haben nach der Studienlage ab einer Polypengröße >5 mm eine der Endoskopie vergleichbare Genauigkeit von etwa 90 %. Für die Computertomographie (CT) ist die Datenlage sehr viel umfangreicher als für die Magnetresonanztomographie (MRT).
UNASSIGNED: In Deutschland stellen die Nichtverfügbarkeit der CT-Kolographie (CTC) im Screening aus Strahlenschutzgründen und die nicht ausreichende Etablierung der MRT eine große Herausforderung dar. Jeder Radiologe sollte die Klassifikation mittels CT Colonography Reporting and Data System (C-RADS) kennen. Dabei werden die Kriterien CT-Dichte, Morphologie, Größe und Lokalisation zur Klassifikation herangezogen. Die Klassifikation nach C‑RADS erfolgt in die Kategorien C0 (inadäquate Studie), C1 (unauffällig), C2a (unklar), C2b (benigne), C3 (verdächtig) und C4 (maligne) sowie extrakolonisch E1/2 (keine klinisch bedeutsamen Befunde) E3 (vermutlich unbedeutende Befunde) und E4 (vermutlich bedeutende Befunde).

Colorectal cancer is the second leading cause of cancer-related mortality in adults in the United States. Despite compelling evidence of improved outcomes in colorectal cancer, screening rates are not optimal. This study aimed to characterize colorectal cancer screening trends over the last two decades and assess the impact of various screening modalities on overall colorectal cancer screening rates. Using National Health Interview Survey data from 2005 to 2021, we examined colorectal cancer screening [colonoscopy, multitarget stool DNA (mt-sDNA), fecal occult blood test (FOBT)/fecal immunochemical test, sigmoidoscopy, CT colonography] rates among adults ages 50-75 years (n = 85,571). A pseudo-time-series cross-sectional (pseudo-TSCS) analysis was conducted including a random effects generalized least squares regression model to estimate the relative impact of each modality on changes in colorectal cancer screening rates. Among 50 to 75 year olds, the estimated colorectal cancer screening rate increased from 47.7% in 2005 to 69.9% in 2021, with the largest increase between 2005 and 2010 (47.7%-60.7%). Rates subsequently plateaued until 2015 but increased from 63.5% in 2015 to 69.9% in 2018. This was primarily driven by the increased use of mt-sDNA (2.5% in 2018 to 6.6% in 2021). Pseudo-TSCS analysis results showed that mt-sDNA contributed substantially to the increase in overall screening rates (77.3%; P < 0.0001) between 2018 and 2021. While colorectal cancer screening rates increased from 2005 to 2021, they remain below the 80% goal. The introduction of mt-sDNA, a noninvasive screening test may have improved overall rates. Sustained efforts are required to further increase screening rates to improve patient outcomes and offering a range of screening options is likely to contribute to achieving this goal.
UNASSIGNED: This retrospective study highlights the importance of convenient stool-based colorectal cancer screening options to achieve the national goal of 80% for overall colorectal cancer screening rates. Empowering screening-eligible individuals with a choice for their colorectal cancer screening tests is imperative.

OBJECTIVE: This study aimed to evaluate bowel preparation burden, rectal pain and abdominal discomfort levels and to determine the association between demographic characteristics and those levels among participants undergoing CT colonography and colonoscopy.
METHODS: A cross-sectional survey was conducted in eligible Thai citizens who consented to participate all four visits of a free colorectal cancer screening protocol. Three levels (mild, moderate and severe) of burden, pain and discomfort were used to ask the perspective of participants at the final visit, one week after undergoing those two procedures.
RESULTS: Data from 1,271 participants completed for analyses - females 815 (64.1%), males 456 (35.9%). The majority of participants experienced mild burden, pain and discomfort. Association between characteristic groups and burden levels differed regarding own income, chronic disease and laxative. Between characteristic groups and pain and discomfort levels differed regarding own income and chronic disease. Participants without their own income rated severe burden lower than those who had (p<0.001), but those without chronic disease rated moderate burden lower than who had (p=0.003). Participants prepared bowel with spilt-dose of PEG rated moderate burden higher than those who prepared with NaP (p<0.001). Participants undergoing CT colonography without their own income and presenting no chronic disease faced severe rectal pain lower than those who had (p<0.001 and p=0.04). Participants without their own income rated moderate and severe abdominal discomfort lower than those who had (p<0.01 and p=0.008). Participants undergoing colonoscopy without their own income and no chronic diseases faced severe rectal pain lower than those who had (p<0.001 and p=0.007). Participants without their own income and no chronic disease rated severe abdominal discomfort lower than those who had (p<0.001 and p=0.005).
CONCLUSIONS: Evaluating the perspectives of customers alongside quality improvement and innovation to reduce unpleasant experiences remains needed in CT colonography and colonoscopy to promote CRC screening.

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Background The natural history of colorectal polyps is not well characterized due to clinical standards of care and other practical constraints limiting in vivo longitudinal surveillance. Established CT colonography (CTC) clinical screening protocols allow surveillance of small (6-9 mm) polyps. Purpose To assess the natural history of colorectal polyps followed with CTC in a clinical screening program, with histopathologic correlation for resected polyps. Materials and Methods In this retrospective study, CTC was used to longitudinally monitor small colorectal polyps in asymptomatic adult patients from April 1, 2004, to August 31, 2020. All patients underwent at least two CTC examinations. Polyp growth patterns across multiple time points were analyzed, with histopathologic context for resected polyps. Regression analysis was performed to evaluate predictors of advanced histopathology. Results In this study of 475 asymptomatic adult patients (mean age, 56.9 years ± 6.7 [SD]; 263 men), 639 unique polyps (mean initial diameter, 6.3 mm; volume, 50.2 mm3) were followed for a mean of 5.1 years ± 2.9. Of these 639 polyps, 398 (62.3%) underwent resection and histopathologic evaluation, and 41 (6.4%) proved to be histopathologically advanced (adenocarcinoma, high-grade dysplasia, or villous content), including two cancers and 38 tubulovillous adenomas. Advanced polyps showed mean volume growth of +178% per year (752% per year for adenocarcinomas) compared with +33% per year for nonadvanced polyps and -3% per year for unresected, unretrieved, or resolved polyps (P < .001). In addition, 90% of histologically advanced polyps achieved a volume of 100 mm3 and/or volume growth rate of 100% per year, compared with 29% of nonadvanced and 16% of unresected or resolved polyps (P < .001). Polyp volume-to-diameter ratio was also significantly greater for advanced polyps. For polyps observed at three or more time points, most advanced polyps demonstrated an initial slower growth interval, followed by a period of more rapid growth. Conclusion Small colorectal polyps ultimately proving to be histopathologically advanced neoplasms demonstrated substantially faster growth and attained greater overall size compared with nonadvanced polyps. Clinical trial registration no. NCT00204867 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Dachman in this issue.

The CT Colonography Reporting and Data System (C-RADS) has withstood the test of time and proven to be a robust classification scheme for CT colonography (CTC) findings. C-RADS version 2023 represents an update on the scheme used for colorectal and extracolonic findings at CTC. The update provides useful insights gained since the implementation of the original system in 2005. Increased experience has demonstrated confusion on how to classify the mass-like appearance of the colon consisting of soft tissue attenuation that occurs in segments with acute or chronic diverticulitis. Therefore, the update introduces a new subcategory, C2b, specifically for mass-like diverticular strictures, which are likely benign. Additionally, the update simplifies extracolonic classification by combining E1 and E2 categories into an updated extracolonic category of E1/E2 since, irrespective of whether a finding is considered a normal variant (category E1) or an otherwise clinically unimportant finding (category E2), no additional follow-up is required. This simplifies and streamlines the classification into one category, which results in the same management recommendation.

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BACKGROUND: The impact of computed tomography (CT)-detected extramural venous invasion on the recurrence of colon cancer is not fully understood. The aim of this study was to investigate the clinical significance of extramural venous invasion diagnosed before surgery by contrast-enhanced CT colonography using three-dimensional multiplanar reconstruction images.
METHODS: Patients with colon cancer staged greater than or equal to T2 and/or stage I-III who underwent contrast-enhanced CT colonography between 2013 and 2018 at the National Cancer Center Hospital in Japan were retrospectively investigated for CT-detected extramural venous invasion. Inter-observer agreement for the detection of CT-detected extramural venous invasion was evaluated and Kaplan-Meier survival curves were plotted for recurrence-free survival using CT-TNM staging and CT-detected extramural venous invasion. Preoperative clinical variables were analysed using Cox regression for recurrence-free survival.
RESULTS: Out of 922 eligible patients, 544 cases were analysed (50 (9.2 per cent) were diagnosed as positive for CT-detected extramural venous invasion and 494 (90.8 per cent) were diagnosed as negative for CT-detected extramural venous invasion). The inter-observer agreement for CT-detected extramural venous invasion had a κ coefficient of 0.830. The group positive for CT-detected extramural venous invasion had a median follow-up of 62.1 months, whereas the group negative for CT-detected extramural venous invasion had a median follow-up of 60.7 months. When CT-TNM stage was stratified according to CT-detected extramural venous invasion status, CT-T3 N(-)extramural venous invasion(+) had a poor prognosis compared with CT-T3 N(-)extramural venous invasion(-) and CT-stage I (5-year recurrence-free survival of 50.6 versus 89.3 and 90.1 per cent respectively; P < 0.001). In CT-stage III, the group positive for CT-detected extramural venous invasion also had a poor prognosis compared with the group negative for CT-detected extramural venous invasion (5-year recurrence-free survival of 52.0 versus 78.5 per cent respectively; P = 0.003). Multivariable analysis revealed that recurrence was associated with CT-T4 (HR 3.10, 95 per cent c.i. 1.85 to 5.20; P < 0.001) and CT-detected extramural venous invasion (HR 3.08, 95 per cent c.i. 1.90 to 5.00; P < 0.001).
CONCLUSIONS: CT-detected extramural venous invasion was found to be an independent predictor of recurrence and could be used in combination with preoperative TNM staging to identify patients at high risk of recurrence.

BACKGROUND: Colorectal cancer (CRC) is a significant contributor to cancer-related morbidity and mortality. Biopsy remains the gold standard for CRC diagnosis, but invasive testing may not be preferred as an initial diagnostic procedure. Therefore, alternative non-invasive approaches are needed. Circulating tumor cells (CTC) present in the bloodstream have great potential as a non-invasive diagnostic marker for CRC patients. This study aimed to assess the diagnostic potential of CTC in CRC as an adjunctive diagnostic method using a subjective manual identification method and laser capture microdissection at 40x magnification.
METHODS: A cross-sectional study was conducted on adult patients suspected to have CRC at Dr. Cipto Mangunkusumo National General Hospital, Jakarta, between November 2020 and March 2021. CTC analysis was performed using the negative selection immunomagnetic method with Easysep™ and the CD44 mesenchymal tumor marker. The identification and quantification of CTC were conducted manually and subjectively, with three repetitions of cell counting per field of view at 40x magnification.
RESULTS: Of 80 subjects, 77.5% were diagnosed with CRC, while 7.5% and 15% exhibited adenomatous polyps and inflammatory/hyperplastic polyps, respectively. The diagnostic analysis of CTC for detecting CRC (compared to polyps) using a CTC cutoff point of >1.5 cells/mL suggested sensitivity, specificity, and positive predictive value (PPV) of 50%, 88.89%, and 93.94%. Additionally, the negative predictive value (NPV), as well as the positive and negative likelihood ratio (PLR and NLR) were 34.04%, 4.5, and 0.56, respectively. The subjective manual identification and quantification of CTC were performed at 40x magnification using laser capture microdissection.
CONCLUSIONS: This study assessed the diagnostic potential of CTC examination in CRC as an adjunctive diagnostic method using the subjective manual identification method and laser capture microdissection at 40x magnification. Despite the limitations associated with subjective cell counting, the results showed 50% sensitivity and 88.89% specificity in diagnosing CRC. Further studies are needed to optimize the manual identification process and validate the clinical utility of CTC analysis in CRC patients.

The American College of Physicians (ACP) update of their standing guidance statement for colorectal-cancer screening in asymptomatic average-risk adults was recently published to assist clinicians with implementing evidence-based patient care. After assessing existing guideline literature, the ACP recommended five actions: consider not screening adults ages 45 to 49 years; stop screening adults older than 75 years; discuss benefits, harms, costs, availability, frequency, and patient values/preferences with patients prior to choosing a screening method; and when choosing, recommend biennial rather than annual use of a fecal immunochemical test or a guaiac fecal occult blood test and avoid recommending computed tomography colonography or stool DNA tests. While the ACP guidelines are rigorous, well-intended, and considerate of patients\' input, their greatest impact may result from highlighting the need for researchers to help frontline clinicians to describe the risk, costs, and benefits/harms of various colorectal-cancer screening strategies in an effective, yet time-efficient, manner given the all-too-brief annual patient encounters. In the United States, reimbursement is still dependent on U.S. Preventive Services Task Force recommendations which are somewhat more liberal in contrast to the ACP\'s approach which strongly favors randomized, controlled trial evidence to guide the delivery of prevention and screening services to asymptomatic average-risk patients.