Computed tomographic colonography in preoperative evaluation of colorectal tumors: a prospective study. Surg Endosc. 2011;25:2344-2349. [PMID: 21416185 PMCID: PMC3116126 DOI: 10.1007/s00464-010-1566-0]

Synchronous colorectal cancer using CT colonography vs. other means: a systematic review and meta-analysis

OBJECTIVES

The objective of our study was to systematically review the evidence about synchronous colorectal cancer diagnosed with or without computed tomography colonography (CTC).

MATERIALS AND METHODS

Two systematic searches were performed (PubMed and EMBASE) for studies reporting the prevalence of synchronous colorectal cancer (CRC): one considering patients who underwent CTC and the another one considering patients who did not undergo CTC. A three-level analysis was performed to determine the prevalence of patients with synchronous CRC in both groups of studies. Heterogeneity was explored for multiple variables. Pooled prevalence and 95% confidence interval (CI) were calculated. A quality assessment (STROBE) was done for the studies.

RESULTS

For CTC studies, among 2645 articles initially found, 21 including 1673 patients, published from 1997 to 2018, met the inclusion criteria. For non-CTC studies, among 6192 articles initially found, 27 including 111,873 patients published from 1974 to 2015 met the inclusion criteria. The pooled synchronous CRC prevalence was 5.7% (95% CI 4.7%-7.1%) for CTC studies, and 3.9% (95% CI 3.3%-4.4%) for non-CTC studies, with a significant difference (p = 0.004). A low heterogeneity was found for the CTC group (I² = 10.3%), whereas a high heterogeneity was found in the non-CTC group of studies (I² = 93.5%), and no significant explanatory variables were found. Of the 22 STROBE items, a mean of 18 (82%) was fulfilled by CTC studies, and a mean of 16 (73%) by non-CTC studies.

CONCLUSIONS

The prevalence of synchronous CRC was about 4-6%. The introduction of CTC is associated with a significant increase of the prevalence of synchronous CRCs.

Combined assessment using optical colonoscopy and computed tomographic colonography improves the determination of tumor location and invasion depth

INTRODUCTION

An accurate assessment of the depth of tumor invasion in patients with colon cancer is an important part of the preoperative evaluation. Whether computed tomographic colonography (CTC) or optical colonoscopy (OC) is better to accurately determine tumor location and invasion depth has not been definitively determined. The aim of this study was to determine the diagnostic accuracy of tumor localization and tumor invasion depth of colon cancer by preoperative OC alone or combined with CTC.

METHODS

Study participants include 143 patients who underwent both preoperative CTC using automated CO₂ insufflation and OC from July 2012 to August 2013.

RESULTS

The accuracy of tumor localization was significantly better with CTC than with OC (OC, 90%; CTC, 98%; P < 0.05). No tumor in the descending colon was localized accurately via OC alone. The accuracy of tumor invasion depth was better with CTC plus OC than with OC alone (OC, 55%; CTC, 73%; P < 0.05).

CONCLUSIONS

OC combined with CTC provides a more accurate preoperative determination of tumor localization and invasion depth than OC alone.

Predictors of incomplete optical colonoscopy using computed tomographic colonography

BACKGROUND/AIMS

Optical colonoscopy (OC) is the primary modality for investigation of colonic pathology. Although there is data on demographic factors for incomplete OC, paucity of data exists for anatomic variables that are associated with an incomplete OC. These anatomic variables can be visualized using computed tomographic colonography (CTC). We aim to retrospectively identify variables associated with incomplete OC using CTC and develop a scoring method to predict the outcome of OC.

PATIENTS AND METHODS

In this case-control study, 70 cases ( with incomplete OC) and 70 controls (with complete OC) were identified. CTC images of cases and controls were independently reviewed by a single CTC radiologist. Demographic and anatomical parameters were recorded. Data was examined using descriptive linear statistics and multivariate logistic regression model.

RESULTS

On analysis, female gender (80% vs 58.6% P = 0.007), prior abdominal/pelvic surgeries (51.4% vs 14.3% P < 0.001), colonic length (187.6 ± 30.0 cm vs 163.8 ± 27.2 cm P < 0.001), and number of flexures (11.4 ± 3.1 vs 8.4 ± 2.9 P < 0.001) increased the risk for incomplete OC. No significant association was observed for increasing age (P = 0.881) and history of severe diverticulosis (P = 0.867) with incomplete OC. A scoring system to predict the outcome of OC is proposed based on CTC findings.

CONCLUSION

Female gender, prior surgery, and increasing colonic length and tortuosity were associated with incomplete OC, whereas increasing age and history of severe diverticulosis were not. These factors may be used in the future to predict those patients who are at risk of incomplete OC.

CT colonography for evaluation of colorectal cancer

AIM: To evaluate the value of computed tomography colonography (CTC) in the evaluation of colorectal cancer by comparing its performance with colonoscopy.

METHODS: Forty-one patients who were diagnosed with colorectal cancer by colonoscopic biopsy and underwent CTC and colonoscopy were included in the study. CTC and colonoscopy were compared for their performance in the evaluation of colorectal cancer.

RESULTS: The locations of tumors revealed by CTC and colonoscopy were consistent. However, colonoscopy had its limitation in determining the size of the tumor, and tumor size was measured by colonoscopy in 54% (23/43) of cases , in contrast to 95% (41/43) of cases by CTC. There was no statistical significance in the pathological type revealed by the two techniques (P = 0.621). Colonoscopy failed to evaluate the condition outside the intestinal tract and the proximal colon in cases with colon obstruction, resulting in incomplete examination. The grade of subjective tolerability was significantly lower for colonoscopy than for CTC (P = 0.000).

CONCLUSION: CTC can evaluate colorectal cancer effectively, although it cannot replace colonoscopy entirely. CTC can be chosen as a preferred means for patients who cannot tolerate colonoscopy as well as patients who have incomplete colonoscopy examination.

Role of preoperative CT colonography in patients with colorectal cancer

In patients with colorectal cancer (CRC), accurate preoperative evaluation is essential for a correct therapeutic plan. Colonoscopy and intravenous contrast-enhanced computed tomography (CT) are currently recommended in the preoperative work-up for CRC. Preoperative colonoscopy has some limitations such as misdiagnosis of synchronous cancers in cases of incomplete exploration of the colon and inaccurate tumor localization. Intravenous contrast-enhanced CT successfully documents distant metastases although it sometimes enables unsatisfactory locoregional staging. Computed tomography colonography (CTC) is obtained after gas insufflation of the colon and offers a comprehensive preoperative evaluation in patients with CRC, including a definition of the segmental location of the tumor, presence of synchronous lesions or lack thereof, and fairly accurate locoregional staging. CTC has some limitations, including a lack of biopsy capability, suboptimal sensitivity for synchronous small polyps, and unsatisfactory nodal staging. Bearing in mind these limitations, CTC could be employed as a “one-stop-shop” examination for preoperative assessment in patients with CRC.