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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Comparison of colonic stenting and open surgery for malignant large bowel obstruction

HS Tilney, RE Lovegrove, S Purkayastha, PS Sains, GK Weston-Petrides, AW Darzi, PP Tekkis, and AG Heriot.

Review published: 2007.

CRD summary

The authors concluded that stenting was an effective palliative treatment for malignant obstruction of the large bowel, with short hospital stays and low rates of stoma formation in comparison with open surgery. The conclusions were based on the statistical combination of data from randomised and non-randomised studies and the results differed between studies; the reliability of these conclusions is therefore unclear.

Authors' objectives

To compare the outcomes of colonic stents and open surgery in the management of malignant large bowel obstruction.

Searching

MEDLINE, EMBASE and the Cochrane Library were searched from 1990 to August 2005; the search terms were reported. The references from retrieved studies were also checked. No language restrictions were employed.

Study selection

Study designs of evaluations included in the review

Comparative studies were eligible for inclusion. Randomised controlled trials (RCTs) prospective and retrospective cohort studies, and case-control studies were included in the review.

Specific interventions included in the review

Studies that compared colonic stents with open surgery were eligible for inclusion in the review.

Participants included in the review

Studies of patients with malignant large bowel obstruction were eligible for inclusion. The patients in the included studies had the following types of cancer: colorectal, ovarian and disseminated upper gastrointestinal malignancy. Studies including patients treated with colonic stents for benign strictures were excluded from the review, unless the results for these patients were reported separately.

Outcomes assessed in the review

Eligible studies reported at least one of the following outcomes: treatment details, including length of hospital stay, intensive care bed usage and success rates for colonic stent procedure; functional recovery, including time to first bowel movement and time to toleration of oral diet; short-term adverse events, including operative mortality, medical complications, surgical complications and stent-related complications; and long-term outcomes, including long-term survival and the proportion of patients with a stoma. The studies were required to report results for the two techniques separately. Studies were also excluded if the standard deviation of the mean or the range was not reported for continuous variables.

How were decisions on the relevance of primary studies made?

Two reviewers independently assessed studies for inclusion in the review.

Assessment of study quality

The authors did not state how the papers were assessed for validity, or how many reviewers performed the assessment. The studies were assessed for validity using a modified form of the Newcastle-Ottawa scale, which assesses patient selection, comparability of the groups and assessment of outcome. Studies that score five or more stars are considered to be the highest quality.

Data extraction

Two reviewers independently performed the data extraction.

Studies reporting zero events for the outcome of interest in both treatment groups were excluded from the analysis. Odds ratios (ORs) were calculated for dichotomous data and weighted mean differences (WMDs) for continuous data, along with the respective 95% confidence intervals (CIs).

Methods of synthesis

How were the studies combined?

The studies were combined in random-effects meta-analyses using the Mantel-Haenszel method. Pooled ORs and pooled WMDs were calculated with 95% CIs. Publication bias was assessed using a funnel plot.

How were differences between studies investigated?

Statistical heterogeneity was assessed using the chi-squared and I-squared statistics. Differences between the studies were further investigated through sensitivity analyses in which only the following groups of studies were included: higher quality studies, studies reporting only on patients with obstruction due to colorectal cancer, studies with 35 patients or more, and studies that employed an intention-to-treat analysis.

Results of the review

Ten studies with a total of 451 patients were included in the review. There were 2 RCTs (n=52), 7 cohort studies (n=361), of which three were prospective (n=168) and four retrospective (n=193), and one case-control study (n=38).

Evidence of publication bias for all studies reporting length of hospital stay was detected; this was not found for higher quality studies but only 3 studies were plotted.

Seven studies, including the 2 RCTs, scored five or more stars on the Newcastle-Ottawa scale and were therefore considered to be of a higher quality.

Treatment details.

Stents were successfully implanted in 92.6% of patients (226 out of 244).

Hospital stay (6 studies): patients treated with stents had a shorter hospital stay (WMD -7.72, 95% CI: -11.41, -4.02, p<0.001) than those undergoing open surgery. Statistically significant heterogeneity between the studies was detected (p<0.001).

Intensive care requirement (3 studies): patients treated with stents were significantly less likely to require treatment in an intensive care unit than those undergoing open surgery (OR 0.07, 95% CI: 0.01, 0.31, p<0.001).

Short-term adverse events.

stent patients were significantly less likely to experience post-procedural medical complications (OR 0.18, 95% CI: 0.08, 0.40, p<0.001; based on 6 studies) and post-procedural mortality (OR 0.45, 95% CI: 0.22, 0.91, p<0.03; based on 7 studies). No significant heterogeneity was detected for either meta-analysis.

Long-term outcomes

Stoma requirement (8 studies): patients treated with stents were significantly less likely to undergo stoma formation at some point in their treatment (OR 0.02, 95% CI: 0.01, 0.08, p<0.001). Statistically significant heterogeneity was detected (p=0.01).

Survival (3 studies): there was no significant difference between the two groups in long-term survival (WMD 14.72, 95% CI: -77.98, 107.4, p>0.05). Statistically significant heterogeneity was detected (p=0.001).

Cost information

Two studies reported on the cost of treatment. One study found that stent insertion was 6.9% more expensive than open surgery, while the other study found that stenting cost £1,760 less than open surgery.

Authors' conclusions

Colonic stenting was an effective palliative treatment for malignant bowel obstruction, with short hospital stays and a low rate of stoma formation, but data on quality of life and economic evaluation were limited. There was no evidence of differences in long-term survival between patients treated with stents and subsequent resection and those undergoing emergency bowel resection.

CRD commentary

The review question was clear, as were the inclusion criteria for the interventions, participants and outcomes; those for study design had to be inferred. The search was adequate, and the lack of any language restrictions reduces the likelihood that relevant reports were not included in the review. However, the authors did not report any attempts to identify unpublished studies, thus potentially increasing the likelihood of excluding relevant studies. They did, however, conduct a formal assessment of publication bias. The authors used appropriate methods to minimise reviewer bias and error when selecting studies for the review and extracting the data, but did not report using such measures in the assessment of study validity, although this assessment did employ appropriate criteria.

The decision to use meta-analysis to statistically combine the data from randomised and non-randomised studies means that it is difficult to determine the reliability of the results of such an analysis. In addition, significant heterogeneity was found for some analyses and, in the absence of results from individual studies or forest plots, it was not possible to determine if relevant studies showed similar direction of treatment effects. It is therefore difficult to ascertain the reliability of the conclusions of the review.

Implications of the review for practice and research

Practice: The authors did not make any recommendations for practice.

Research: The authors stated that a formal evaluation of the potential benefits of colonic stents for palliation of incurable colonic cancer, in terms of quality of life and financial implications, is required.

Bibliographic details

Tilney H S, Lovegrove R E, Purkayastha S, Sains P S, Weston-Petrides G K, Darzi A W, Tekkis P P, Heriot A G. Comparison of colonic stenting and open surgery for malignant large bowel obstruction. Surgical Endoscopy 2007; 21(2): 225-233. [PubMed: 17160651]

Indexing Status

Subject indexing assigned by NLM

MeSH

Aged; Colectomy /adverse effects /methods; Colonoscopy /adverse effects /methods; Colorectal Neoplasms /mortality /pathology /surgery; Confidence Intervals; Female; Follow-Up Studies; Humans; Intestinal Obstruction /mortality /pathology /surgery; Length of Stay; Male; Middle Aged; Neoplasm Staging; Odds Ratio; Palliative Care /methods; Postoperative Complications /epidemiology; Randomized Controlled Trials as Topic; Risk Assessment; Stents; Survival Analysis

AccessionNumber

12007000413

Database entry date

31/08/2007

Record Status

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.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 17160651