Less is more-the best test for anastomotic leaks in rectal cancer patients prior to ileostomy reversal

Abstract

Purpose: No clear consensus exists on how to routinely assess the integrity of the colorectal anastomosis prior to ileostomy reversal. The objective of this study was to evaluate the accuracy of contrast enema, endoscopic procedures, and digital rectal examination in rectal cancer patients in this setting.

Methods: A systematic literature search was performed. Studies assessing at least one index test for which a 2 × 2 table was calculable were included. Hierarchical summary receiver operating characteristic curves were calculated and used for test comparison. Paired data were used where parameters could not be calculated. Methodological quality was assessed with the QUADAS-2 tool.

Results: Two prospective and 11 retrospective studies comprising 1903 patients were eligible for inclusion. Paired data analysis showed equal or better results for sensitivity and specificity of both endoscopic procedures and digital rectal examination compared to contrast enema. Subgroup analysis of contrast enema according to methodological quality revealed that studies with higher methodological quality reported poorer sensitivity for equal specificity and vice versa. No case was described where a contrast enema revealed an anastomotic leak that was overseen in digital rectal examination or endoscopic procedures.

Conclusions: Endoscopy and digital rectal examination appear to be the best diagnostic tests to assess the integrity of the colorectal anastomosis prior to ileostomy reversal. Accuracy measures of contrast enema are overestimated by studies with lower methodological quality. Synopsis of existing evidence and risk-benefit considerations justifies omission of contrast enema in favor of endoscopic and clinical assessment.

Trial registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42019107771.

Keywords: Anastomotic leak; Contrast enema; Diagnostic test accuracy; Digital rectal examination; Endoscopy; Ileostomy reversal.

Fig. 1

QUADAS-2 questionnaire results listed by individual study

Fig. 2

Overall diagnostic test accuracy of contrast enema. Each individual study is plotted by respective sensitivity and (1 − specificity). Test accuracy thus improves from bottom right corner to top left corner. As no fixed threshold can be assumed, a hierarchical summary receiver operating characteristic (HSROC) curve was calculated to summarize the findings. The HSROC curve represents the underlying correlation of sensitivity and specificity of all studies

Fig. 3

Subgroup analysis of contrast enema studies according to risk of bias. Each individual study is plotted by respective sensitivity and (1 − specificity). Test accuracy thus improves from bottom right corner to top left corner. For comparison according to risk of bias, the underlying diagnostic test accuracy of the groups with higher and lower risk of bias was assessed separately. As no fixed threshold can be assumed, a hierarchical summary receiver operating characteristic (HSROC) curve was calculated to summarize the findings for each group. The HSROC represents the underlying correlation of sensitivity and specificity of all studies in each group

Fig. 4

Paired data analysis of contrast enema and endoscopic procedures. Index test results of each comparative study are plotted by respective sensitivity and (1 − specificity). Test accuracy thus improves from bottom right corner to top left corner. Contrast enema and endoscopic results of each study are connected with a dotted line to aid visual interpretation

Fig. 5

Paired data analysis of contrast enema and digital rectal examination. Index test results of comparative studies are plotted by respective sensitivity and (1 − specificity). Test accuracy thus improves from bottom right corner to top left corner. Contrast enema and digital rectal examination results of each study are connected with a dotted line to aid visual interpretation

Fig. 6

Paired data analysis of endoscopic procedures and digital rectal examination. Index test results of comparative studies are plotted by respective sensitivity and (1 − specificity). Test accuracy thus improves from bottom right corner to top left corner. Endoscopic and digital rectal examination results of each study are connected with a dotted line to aid visual interpretation