This review of endoscopic ultrasound for T-staging of rectal cancer tumours concluded that endoscopic ultrasound should be the investigation of choice to T-stage rectal cancers. Given concerns regarding the analysis, and the poor quality of the included studies, the conclusions should be treated with some caution.

To evaluate the accuracy of endoscopic ultrasound in T-staging of rectal cancers.

PubMed, Ovid journals, CINAHL, American College of Physicians (ACP) journals, DARE, International Pharmaceutical Abstracts, HealthStar and Cochrane Central Register of Controlled Trials were searched from 1980 to January 2008. Search terms were reported.

Studies of the use of endoscopic ultrasound to determine the tumour T-stage of rectal cancers (definitions supplied), compared with surgical histology, that provided sufficient data for diagnostic outcomes to be calculated, were eligible for inclusion.

Participant details beyond the inclusion of patients with rectal cancer were not provided.

Two independent reviewers selected studies for inclusion. Differences were resolved by consensus.

Study quality was assessed using a 14-point QUADAS (Quality Assessment of Studies of Diagnostic Accuracy
included in Systematic Reviews) system.

The authors did not state how many reviewers performed the quality assessment.

The number of true and false positive and true and false negatives was extracted, from which sensitivity, specificity, the diagnostic odds ratio, positive and negative likelihood ratios were calculated. Corresponding 95% confidence intervals were calculated using the F distribution method. Cells containing zero had 0.5 added. Authors were contacted for additional data when necessary.

Two reviewers independently extracted data; differences were resolved by consensus.

Pooled estimates of sensitivity and specificity with 95% confidence intervals were calculated using a fixed-effect and random-effects meta-analyses. Results from the fixed-effect model were presented. Heterogeneity was investigated using the likelihood ratio test and Cochran's Q statistic. Summary receiver operating characteristic curves were plotted, and the area under the curve, with a standard error calculated. The summary receiver operating characteristic model used was not specified. An analysis was conducted using date of publication as a surrogate for technological advancement. Publication bias was assessed using funnel plots, and the Egger and Begg-Mazumdar tests.

Forty two studies met the inclusion criteria (n=5,039 patients). All studies scored 4 or 5 out of a possible 14 on QUADAS. Patient recruitment was described as consecutive in 38 studies, and prospective in four studies.

Sensitivity: Pooled estimates of sensitivity of endoscopic ultrasound to determine T stages of rectal cancer were: 88% (95% confidence interval (CI): 85.3 to 90.0; 39 studies) for T-stage 1; 81% (95% CI: 77.9 to 82.9; 41 studies) for T-stage 2; 96% (95% CI: 95.4 to 97.2; 41 studies) for T-stage 3; and 95% (95% CI: 92.4 to 97.5; 32 studies) for T-stage 4.

Specificity: Pooled estimates of specificity of endoscopic ultrasound to determine T stages of rectal cancer were: 98% (95% CI: 97.8 to 98.7; 39 studies) for T-stage 1; 96% (95% CI: 94.9 to 96.3; 41 studies) for T-stage 2; 91% (95% CI: 89.5 to 91.7; 41 studies) for T-stage 3; and 98% (95% CI: 97.8 to 98.7; 32 studies) for T-stage 4.

Results for positive/negative likelihood ratios and diagnostic odds ratio are also reported for each T stage. There was no statistically significant heterogeneity between studies for any analysis. The area under the summary receiver operating characteristic curve ranged from 0.96 to 0.98 for the four T-stages (standard error 0.01 for each T-stage). Pooled estimates of sensitivity, specificity, diagnostic odds ratio, positive/negative likelihood ratios were provided for each T-stage for three time periods. There was no evidence of publication bias.

Endoscopic ultrasound should be the investigation of choice to T-stage rectal cancers.

The authors addressed a clear review question supported by appropriate inclusion criteria. Several relevant sources were searched, but it was unclear whether language restrictions were applied, so language bias can not be ruled out. Data extraction and study selection were conducted in duplicate. Study quality was assessed using appropriate criteria, but the results were not provided for each study and the overall quality of all studies was poor. There were inadequate study details to determine which quality criteria were not met by the studies, or to determine the degree of clinical heterogeneity between study populations. The authors stated that heterogeneity due to diagnostic threshold was present, making the reliability of the pooled estimates for the diagnostic outcomes uncertain. There was also no indication as to how under- or over-staging was treated within the analyses. Given the concerns regarding the analysis highlighted, and poor quality of the included studies, the conclusions should be treated with some caution.

The authors did not state implications for practice or research.

None stated.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.