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Table 2 Characteristics of included reviews

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

Review (origin) Last update Population/interventiona Study types Notes/limitations
Bernard/ANDEM, 1994 [16], (France) July 1993 Any colorectal pathology and other abdominal pathologies (appendicitis, biliary disease, reflux, inguinal hernia) Case series; no RCT or observational study found In French. Paucity of available comparative literature. Broad review addressing all laparoscopic techniques (biliary, hernia, etc.).
Chapman/ASERNIP-S 2000 [17] (Australia) July 1999 Colon cancer (right, left/sigmoid) and animal studies of in vitro/in vivo tumor spread. Excluded: transverse colectomy, APR, total colectomy. RCTs, observational animal studies Limited to English. Inclusion/exclusion of high and mid rectal cancer is not clearly specified. Chose not to pool data. Overlap with Chapman 2001 [19].
Vardulaki/NICE 2000 [18], (UK) 2000 Colorectal cancer. Excluded: case series of < 10 patients. RCTs, observational Extensive methodological description. Rigorous assessment of heterogeneity. Pooling of RCTs and observational data performed separately to avoid bias (for some outcomes). Statistical manipulations to overcome data limitations.
Chapman 2001 [19], (Australia) July 1999 Colon cancer (right, left/sigmoid). Excluded: transverse colectomy, APR, total colectomy. RCTs, observational Limited to English. Inclusion/exclusion of high and mid rectal cancer is not clearly specified. Chose not to pool data. Overlap with Chapman 2000 [17].
Yong 2001 [20], (UK) March 1997 Any colorectal pathology (all operation types) Observational; no RCT found Modification of inclusion/exclusion criteria from protocol based on available studies. Only 13/42 studies had only malignant disease. Pooled certain outcomes by calculating weighted means.
Korolija 2003 [21], (Croatia) January 2000 'Colorectal procedures', unclear RCTs, observational No inclusion/exclusion criteria provided. Not mentioned whether RCTs included (two identified in reference list). Chose to pool outcomes from RCTs, observational studies, case series together (no mention of appropriateness).
Abraham 2004 [22], (Australia) December 2002 Colorectal cancer (right hemicolectomy, left hemicolectomy, rectosigmoid resection, APR, others) RCTs Limited to English. Study selection on basis of reported outcomes.
Reza/UETS 2004 [23], (Spain) September 2004 Colorectal cancer. Excluded: combination of benign and malignant pathologies, immune outcomes. RCTs, systematic reviews, meta-analyses In Spanish. Pre-2000 RCTs not included. No pooling of outcomes except survival and recurrence (reason unclear).
Poutignat/Haute Autorité de Santé 2005 [24], (France) 2003 Colorectal cancer. Excluded: metastatic disease, combined benign and malignant pathologies, non-intention-to-treat studies or those excluding converted patients. RCTs, observational, meta-analysis In French, limited to English and French. Unclear from text whether inclusion/exclusion criteria chosen a priori or after literature search by group of experts. Chose not to pool outcomes, qualitative analysis.
Manterola 2005 [25], (Chile) December 2002 Colon cancer (right, transverse, left, sigmoid). Excluded: rectal cancer, perforated or obstructing cancer, metastasis, recurrent cancer, invasion into adjacent bowel/organs, polyps. RCTs, observational In Spanish, limited to English, Spanish, French, Italian. Methodology score created by review authors. Controlled series and RCTs broken down into individual case series yielding 6 laparoscopy and 11 open series in total.
Schwenk 2005 [26], (Germany) January 2005 Colorectal pathologies (benign or malignant, for curative or palliative resection) RCTs Cochrane Review, protocol published in 2001. Extensive methodological description. Results for different pathologies pooled together.
Aziz 2006 [27], (UK) 2004 Rectal cancer (described as anterior resection or APR) RCTs, observational Extensive quantitative assessment of heterogeneity. Results for RCTs and observational studies pooled (no sensitivity analysis comparing RCT to observational data).
Tjandra 2006 [28], (Australia) September 2005 Colon and rectosigmoid cancer. Excluded: rectal cancer, distant metastases. RCTs Limited to English. Effect of heterogeneity on results not clear/not documented.
Reza 2006 [29], (Spain) November 2005 Colorectal cancer. Excluded: papers with mixed malignant/benign populations, immune function as outcome. RCTs, systematic reviews Pre-2000 RCTs not included. Limited description of methodology. No pooling of outcomes except survival and recurrence (reason unclear).
Breukink 2006 [30], (The Netherlands) August 2006 Rectal cancer (undergoing total mesorectal excision) RCTs, observational Cochrane Review, protocol published in 2005. Primary outcome: disease-free survival. Chose not to pool survival data; qualitative analysis.
Gao 2006 [31], (China) June 2005 Rectal cancer RCTs, observational Outcomes considered were selected post hoc after reviewing selected literature. Meta-analysis of RCT and observational data. Incomplete assessment of heterogeneity.
Murray 2006 [10], (UK) May 2005 Colorectal cancer (including laparoscopic or HALS, excluding palliative surgery) RCTs, IPD meta-analyses HTA report (commissioned), protocol published in 2005. Pre-2000 RCTs identified from existing systematic reviews. Extensive description of methodology, rigorous assessment of heterogeneity. Academic-in-confidence data obtained from other authors removed from final report. Includes economic evaluation.
Kahnamoui 2007 [32], (Canada) 2004 Colorectal cancer (right, left, sigmoid, anterior resection, APR) RCTs Defined primary outcome: cancer-related mortality. Extensive methodological description. Quality appraisal list designed by authors.
Noel 2007 [33], (USA) January 2005 Colorectal cancer, IBD, diverticular disease RCTs, observational (controlled) Limited to English. Excluded historical controls with < 50% overlap in accrual periods. Combination of RCT and non-RCT data. No assessment of methodological quality.
Bonjer 2007 [34], (The Netherlands) 2006 Colon cancer (rectal cancer included in at least one of trials) RCTs Minimum 150 patients with primary outcomes of survival. Authors of review are primary investigators in four included trials. Meta-analysis of individual patient data with 3 years of follow-up data.
Jackson 2007 [35], (USA) February 2006 Colorectal cancer (colon and rectosigmoid as per inclusion criteria, but selected RCTs include rectal cancers). Excluded: benign pathologies. RCTs Primary outcome: survival and recurrence. Inclusion/exclusion of mid and low rectal cancer is not clearly specified. Meta-analysis of survival outcomes using time-to-event data. Significant assessment of heterogeneity.
Abraham 2007 [36], (Australia) December 2003 Colorectal cancer (non-metastatic, treated with intention to cure). Excluded: uncontrolled series. Observational Limited to English. Limited to end of 2003. Quality assessment of papers performed but not utilized in analysis (to be reported separately). Limited assessment of heterogeneity.
Kuhry 2007 [37], (Norway) April 2006 Colorectal cancer RCTs In Norwegian, limited to English. Very limited methodological description.
Kuhry 2008 [38], (Norway) January 2008 Colorectal cancer (reporting long-term result, non-metastasized carcinoma) RCTs Cochrane review, protocol published 2002. Meta-analysis of survival outcomes using time-to-event data. Sensitivity analyses performed separately for colon and rectum.
Lourenco 2008 [39], (UK) May 2007 Colorectal cancer. Excluded: patients undergoing palliative treatment. RCTs, IPD meta-analyses Pre-2000 RCTs identified from existing systematic reviews. Extensive description of methodology. Overlap with Murray 2006 [10].
Anderson 2008 [40], (USA) November 2007 Rectal cancer. Excluded: tumors invading adjacent organs, previous pelvic surgery, contraindications to pneumoperitoneum, obstruction, perforation, studies which did not report rectal cancer outcomes separately. RCTs, observational Limited to English language. RCT and observational studies pooled together.
Liang 2008 [41], (China) January 2007 Colorectal cancer. Excluded: emergency surgery (obstruction, perforation), known prohibitive adhesions, studies for which colorectal cancer patients could not be analyzed separately from patients with benign pathologies. RCTs Limited to English. Extensive assessment of heterogeneity.
  1. aLaparoscopic versus open radical oncologic resection is the intervention under study unless stated otherwise.
  2. APR = abdominoperineal resection; HALS = hand-assisted laparoscopic surgery; HTA = Health Technology Assessment; IBD = inflammatory bowel disease; IPD = individual patient data; RCT = randomized controlled trials.