Elsevier

Clinical Radiology

Volume 65, Issue 9, September 2010, Pages 708-719
Clinical Radiology

Original Paper
Diagnostic precision of CT in local staging of colon cancers: a meta-analysis

https://doi.org/10.1016/j.crad.2010.01.024Get rights and content

Aim

To determine the accuracy of computed tomography (CT) in detecting disease with invasion beyond the muscularis propria (MP) and malignant lymph nodes.

Materials and methods

A literature search of Ovid, Embase, the Cochrane database, and Medline using Pubmed, Google™ Scholar and Vivisimo™ search engines was performed to identify studies reporting on the accuracy of CT to predict the staging of colonic tumours. Publication bias was demonstrated by Funnel plots. The sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated using a bivariate random effects model and hierarchical summary operating curves (HSROC) were generated.

Results

Nineteen studies fulfilled all the necessary inclusion criteria. The pooled sensitivity, specificity, DOR for detection of tumour invasion were 86% (95% CI: 78–92%); 78% (95% CI: 71–84%); 22.4 (95% CI: 11.9–42.4). Similarly, the values for nodal detection were 70% (95% CI: 63–73%); 78% (95% CI: 73–82%); 8.1(95% CI: 4.7–14.1). In the subgroup analysis, the best results were obtained in studies utilizing multidetector CT (MDCT).

Conclusion

Preoperative staging CT accurately distinguishes between tumours confined to the bowel wall and those invading beyond the MP; however, it is significantly poorer at identifying nodal status. MDCT provides the best results.

Introduction

The management of most gastrointestinal (GI) malignancies has evolved from adjuvant treatment post-surgical resection to perioperative strategies that incorporate preoperative neoadjuvant therapy. Increasingly, imaging is relied upon to identify locally advanced disease in patients that could derive potential benefit from such neoadjuvant approaches.1, 2, 3, 4

Currently, the treatment of colon cancer is dependent on histological assessment of the resected surgical specimen.5, 6 The preoperative T and N stage of colonic tumours is not always reported as there is uncertainty regarding the accuracy and its clinical significance.7, 8 Computed tomography (CT) has the potential to visualize local tumour characteristics in addition to its role in detecting any distant metastatic disease. It has the advantage of being universally available and easily reproducible. With advances in CT technology and computing software, CT has shown potential not only as a staging tool but also in predicting prognosis.9 There has also been recent interest in developing neoadjuvant treatment strategies for patients with colon cancer because of better compliance and potential to downstage prior to surgical treatment.10

The key feature in predicting prognosis in both colon and rectal tumours is extent of spread of tumour beyond the muscularis propria (MP).9 A number of studies have attempted to assess the T and N stage of colon primary. Many of these studies employed varying techniques and did not report the distinction between good and poor prognosis tumours based on spread beyond MP. Therefore, there is a need to determine the best CT staging technique and how this can improve identification of poor prognostic tumours.

The aim of the present meta-analysis was to undertake a systematic review to determine the accuracy and limitations of CT in identifying poor prognostic factors, such as invasion of the tumour beyond MP and detection of malignant lymph nodes in colon cancers, and to determine which CT techniques achieve the best results.

Section snippets

Literature search

The search was conducted to assess the ability of staging CT to accurately predict the depth of tumour invasion beyond MP and lymph node involvement in patients diagnosed with colon cancer. A literature search of Ovid, Embase, the Cochrane database, and Medline using Pubmed as the search engine was performed to identify studies reporting on the accuracy of CT to predict the staging of colonic tumours. The search was also made using Google™ Scholar, and Vivisimo™ search engines. The last date of

Literature search and selection of studies

The search results yielded 130 studies (Appendix A). The studies comparing the staging of the colon cancer using preoperative CT to the final histology were considered for possible inclusion in the meta-analysis. All review articles were excluded from the study. In one study, the majority of the tumours analysed were rectal lesions (n = 20/25), and hence, this study was excluded.7 Overall, the studies reported a total of 907 patients and distinguished between colon and rectal cancers in 810/907

Discussion

This meta-analysis shows that sensitivity and specificity of differentiating between T1/T2 versus T3/T4 is 86 and 78%, respectively. Therefore, preoperative CT can make this clinically significant distinction with accuracy. The potential future implication is that the technique is safe to enable preoperative stratification and the low FP rate in most studies (Table 3) reduces the risk of prescribing any possible neoadjuvant treatment to early-stage tumours.

The most impressive results have been

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