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The quality of research synthesis in surgery: the case of laparoscopic surgery for colorectal cancer.

Martel G, Duhaime S, Barkun JS, Boushey RP, Ramsay CR, Fergusson DA - Syst Rev (2012)

Bottom Line: Reviews were synthesized, and outcomes were compared qualitatively.Overall survival was evaluated by ten reviews, none of which found a significant difference.Further systematic reviews or meta-analyses are unlikely to be justified without specifying a significantly different research objective.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Surgery, Department of Epidemiology & Community Medicine, and Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada. guillaume.martel@gmail.com

ABSTRACT

Background: Several systematic reviews and meta-analyses populate the literature on the effectiveness of laparoscopic surgery for colorectal cancer. The utility of this body of work is unclear. The objective of this study was to synthesize all such systematic reviews in terms of clinical effectiveness, to appraise their quality, and to determine whether areas of duplication exist across reviews.

Methods: Systematic reviews comparing laparoscopic and open surgery for colorectal cancer were identified using a comprehensive search protocol (1991 to 2008). The primary outcome was overall survival. The methodological quality of reviews was appraised using the Assessment of Multiple Systematic Reviews (AMSTAR) instrument. Abstraction and quality appraisal was carried out by two independent reviewers. Reviews were synthesized, and outcomes were compared qualitatively. A citation analysis was carried out using simple matrices to assess the comprehensiveness of each review.

Results: In total, 27 reviews were included; 13 reviews included only randomized controlled trials. Rectal cancer was addressed exclusively by four reviews. There was significant overlap between review purposes, populations and, outcomes. The mean AMSTAR score (out of 11) was 5.8 (95% CI: 4.6 to 7.0). Overall survival was evaluated by ten reviews, none of which found a significant difference. Three reviews provided a selective meta-analysis of time-to-event data. Previously published systematic reviews were poorly and highly selectively referenced (mean citation ratio 0.16, 95% CI: 0.093 to 0.22). Previously published trials were not comprehensively identified and cited (mean citation ratio 0.56, 95% CI: 0.46 to 0.65).

Conclusions: Numerous overlapping systematic reviews of laparoscopic and open surgery for colorectal cancer exist in the literature. Despite variable methods and quality, survival outcomes are congruent across reviews. A duplication of research efforts appears to exist in the literature. Further systematic reviews or meta-analyses are unlikely to be justified without specifying a significantly different research objective. This works lends support to the registration and updating of systematic reviews.

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Assessment of Multiple Systematic Reviews (AMSTAR) methodological quality scores against time. Red circles represent Cochrane reviews and Health Technology Assessment (HTA) reports.
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Figure 2: Assessment of Multiple Systematic Reviews (AMSTAR) methodological quality scores against time. Red circles represent Cochrane reviews and Health Technology Assessment (HTA) reports.

Mentions: The included systematic reviews were generally of low to moderate quality. The mean AMSTAR methodological quality score was 5.8 (95% CI: 4.6 to 7.0). A total of eight reviews (30%) achieved a score of 9 or greater, and can be considered of high methodological quality. The quality of reviews appears to have improved modestly in time (Figure 2), with all but one high-quality review having been published in 2005 or later. Among high-quality reviews, three were published in traditional journals [32,35,39], three were Cochrane Reviews [26,30,38], and two were HTA reports [10,18].


The quality of research synthesis in surgery: the case of laparoscopic surgery for colorectal cancer.

Martel G, Duhaime S, Barkun JS, Boushey RP, Ramsay CR, Fergusson DA - Syst Rev (2012)

Assessment of Multiple Systematic Reviews (AMSTAR) methodological quality scores against time. Red circles represent Cochrane reviews and Health Technology Assessment (HTA) reports.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3351744&req=5

Figure 2: Assessment of Multiple Systematic Reviews (AMSTAR) methodological quality scores against time. Red circles represent Cochrane reviews and Health Technology Assessment (HTA) reports.
Mentions: The included systematic reviews were generally of low to moderate quality. The mean AMSTAR methodological quality score was 5.8 (95% CI: 4.6 to 7.0). A total of eight reviews (30%) achieved a score of 9 or greater, and can be considered of high methodological quality. The quality of reviews appears to have improved modestly in time (Figure 2), with all but one high-quality review having been published in 2005 or later. Among high-quality reviews, three were published in traditional journals [32,35,39], three were Cochrane Reviews [26,30,38], and two were HTA reports [10,18].

Bottom Line: Reviews were synthesized, and outcomes were compared qualitatively.Overall survival was evaluated by ten reviews, none of which found a significant difference.Further systematic reviews or meta-analyses are unlikely to be justified without specifying a significantly different research objective.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Surgery, Department of Epidemiology & Community Medicine, and Ottawa Hospital Research Institute, The Ottawa Hospital, University of Ottawa, Ottawa, Ontario, Canada. guillaume.martel@gmail.com

ABSTRACT

Background: Several systematic reviews and meta-analyses populate the literature on the effectiveness of laparoscopic surgery for colorectal cancer. The utility of this body of work is unclear. The objective of this study was to synthesize all such systematic reviews in terms of clinical effectiveness, to appraise their quality, and to determine whether areas of duplication exist across reviews.

Methods: Systematic reviews comparing laparoscopic and open surgery for colorectal cancer were identified using a comprehensive search protocol (1991 to 2008). The primary outcome was overall survival. The methodological quality of reviews was appraised using the Assessment of Multiple Systematic Reviews (AMSTAR) instrument. Abstraction and quality appraisal was carried out by two independent reviewers. Reviews were synthesized, and outcomes were compared qualitatively. A citation analysis was carried out using simple matrices to assess the comprehensiveness of each review.

Results: In total, 27 reviews were included; 13 reviews included only randomized controlled trials. Rectal cancer was addressed exclusively by four reviews. There was significant overlap between review purposes, populations and, outcomes. The mean AMSTAR score (out of 11) was 5.8 (95% CI: 4.6 to 7.0). Overall survival was evaluated by ten reviews, none of which found a significant difference. Three reviews provided a selective meta-analysis of time-to-event data. Previously published systematic reviews were poorly and highly selectively referenced (mean citation ratio 0.16, 95% CI: 0.093 to 0.22). Previously published trials were not comprehensively identified and cited (mean citation ratio 0.56, 95% CI: 0.46 to 0.65).

Conclusions: Numerous overlapping systematic reviews of laparoscopic and open surgery for colorectal cancer exist in the literature. Despite variable methods and quality, survival outcomes are congruent across reviews. A duplication of research efforts appears to exist in the literature. Further systematic reviews or meta-analyses are unlikely to be justified without specifying a significantly different research objective. This works lends support to the registration and updating of systematic reviews.

Show MeSH
Related in: MedlinePlus