Included RCTs were examined their risk of bias using the approach advocated by the Cochrane Collaboration . Eight items were appraised: 1 random sequence generation, 2 allocation concealment, 3 blinding of participants and personnel, 4 blinding of outcome assessment, 5 incomplete outcome data, 6 selective reporting, 7 provider expertise bias surgical skills acquisition and learning curves can influence outcomes in procedures-based trials  and 8 other potential sources of bias eg.
Clinical Trials & Research
All eight items were assessed for each trial. Where trials had more than one publication, the trial as a whole as evaluated using all included reports. As well, referenced trial protocols or partial publications not included in this review were also read in an attempt to minimize trial reporting issues. These data were synthesized using descriptive figures. Trials with five or more items with a low risk of bias were arbitrarily defined as high-quality studies. Data from included RCTs and review papers were extracted. Data points were checked for accuracy by a second reviewer and discrepancies were resolved by consensus.
Although each citation was abstracted separately, trials with multiple publications were identified so as to avoid patient duplication.
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Individual trial authors were contacted selectively. Data on overall survival were abstracted in the statistical format provided in individual reports. Relative outcomes were always recorded as a comparison of laparoscopic to open surgery. Where hazard ratios HR for survival and confidence intervals were not provided, available data were utilized to generate hazard ratios for each trial using published methods  — . Briefly, this technique allows one to derive the ln HR and var ln HR from published statistics.
Where this information is unavailable, one can utilize Kaplan-Meier curves to derive conservative estimates of HR. This method assumes that censoring is constant and non-informative across smaller time interval on the Kaplan-Meier curve eg. Expert opinion in the literature was abstracted from review papers separately for colon and rectal cancers. The other options on the scale were as follows: 2 laparoscopy is inferior, 3 laparoscopy is acceptable only within clinical trials, 4 laparoscopy is equivalent with anatomic limitation, 5 laparoscopy is equivalent among experts, and 6 laparoscopy is equivalent in routine clinical practice.
This scale was piloted independently by two reviewers using ten distinct review articles for ease of use and congruence among reviewers.
The primary outcome of overall survival analyzed using standard meta-analytic techniques. Derived HR were pooled using inverse variance methods and random effects models. Random effects models were preferred in this work because of the often non-standardized nature of surgery across trials, the variability in trial quality, and the added statistical conservatism provided by this approach. Where multiple publications of the same RCT were identified, only the most mature survival data were used in this meta-analysis.
In contrast, a cumulative random effects meta-analysis of the primary outcome was also carried out using the earliest available survival data set for each trial, so as to assess the evolution of this outcome in time. All analyses were carried out using Comprehensive Meta-Analysis 2. Grades of opinion for individual review papers were synthesized as yearly proportions, and plotted as a time series. Changing trends in expert opinions were then evaluated visually from these graphs and correlated qualitatively with overall survival data derived from RCTs, as well as compared to the temporal data obtained from the cumulative meta-analysis of overall survival.
A total of 5, single citations were evaluated figure 1.
Corman's Colon and Rectal Surgery: 1 (COLON AND RECTAL SURGERY by Marvin Corman
After screening, a total of 38 reports pertaining to 23 individual RCTs were included  —  see Table S1. A report of long-term data pertaining to a trial already included was also included, as it became available a few weeks after study selection .
The full reference list is available upon request. The smallest multicenter study recruited 3 centers in Greece  , whereas the largest multinational RCT included 48 centers across the United States and Canada  ,  ,  , . Patient recruitment varied widely, ranging from 28 patients for the smallest study from Brazil  to 1, patients for the European COLOR trial  ,  , . A total of eight risk of bias items were assessed individually figure 2.
Two trials also demonstrated other high risks of bias, as they elected to carry out a diagnostic laparoscopy prior to randomization so as to determine whether individual patients could undergo a formal oncologic colorectal resection by laparoscopy  —  ,  , . These three trials were all large-scale multicenter multinational RCTs, contributing a total of 2, patients to this review. Median follow-up time among these trials ranged from 12—95 months.
One trial did not report a median follow-up time period for either intervention group . Seven trials presented sufficient data to obtain hazard ratios. A cumulative meta-analysis using overall survival data as they became available in time for each trial yielded a comparable hazard ratio of 0. The addition of a sixth trial, which included both sigmoid colon and high rectal cancers, did not alter these data significantly not shown.
The addition of a third trial including only rectosigmoid cancer patients to the rectal cancer group yielded a HR of 0. Pre-specified sensitivity analyses based on the risk of bias did not significantly affect the survival results or the degree of heterogeneity data not shown. Nine trials presented sufficient data to allow for meta-analysis.
The range of reported lymph nodes harvested was 5. Distinct trends in expert opinions were identified for colon and rectal cancer. This trend was maintained until Starting in , a second major shift in opinions can be identified, as experts were found to consider laparoscopic surgery equivalent to open surgery in growing proportions. As of , opinion curves were found to have crossed over, with a majority of surgeons favoring equivalency between the two technologies. After , almost no surgeons considered laparoscopy inferior to laparotomy.
Similarly, only four reviewers considered laparoscopy superior to open surgery at any given time point. For rectal cancer figure 5 , experts initially considered laparoscopy inferior to open surgery in — A shift towards equipoise was again noted — albeit not as strongly — from — with 50— In contrast to colon cancer, experts continued to consider laparoscopy inferior to open surgery in variable proportions A much smaller proportion of experts began to regard laparoscopy as equivalent to laparotomy for rectal cancer in onwards, although the rise was much more gradual than for colon cancer.
We have conducted a systematic review and meta-analysis of trials comparing laparoscopic and open surgery for colorectal cancer, addressing the primary outcome of overall survival. In addition, we have synthesized expert opinion on this topic by utilizing the entire body of relevant review literature as a surrogate for the acceptability of this technology among surgeons. In summary, this work identified 23 RCTs presented in 39 distinct published reports comparing laparoscopic and open surgery for patients suffering from colorectal cancer.
A meta-analysis of time-to-event data on overall survival demonstrated the non-inferiority of laparoscopy.
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Although other groups have also previously conducted meta-analyses pertaining to oncologic outcomes  , most have opted to pool survival data using the proportion of patients alive or dead at maximal follow-up. This approach has the potential to introduce bias in a meta-analysis, as the pooling of such a dichotomous outcome involves the combination of trials at different stages of maturity and completely omits information pertaining to the timing of death following cancer surgery.
In order to circumvent these issues, we have pooled hazard ratios, which are more appropriate measures of time-to-event data.
sanneudropmugg.ml Unfortunately, these data are not always reported in clinical trials. As such, we have utilized a combination of published data on hazard ratios where possible, together with best estimations of HR obtained from published survival curves. This statistical approach allowed us to generate the most comprehensive and rigorous meta-analysis of survival data pertaining to laparoscopic and open surgery for colorectal cancer available to date, as well as to confirm the non-inferiority of laparoscopy.
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These results compare favorably with existing meta-analyses  , including those that employed similar statistical methods  , . The current review is also unique in its utilization of cumulative meta-analytic techniques and its comparison to expert opinion. In addition to the above finding, we have also demonstrated that expert opinion pertaining to laparoscopic surgery for colon cancer shifted dramatically in — For rectal cancer, a similar — albeit weaker — trend was noted in In both instances, the majority opinion deemed that laparoscopic surgery was equivalent to open surgery after a long period of time during which this technique had reached clinical equipoise and was considered only acceptable in clinical trials.
We argue that the abrupt shift in opinion in was a direct result of the publication of the first moderate-size RCT by Lacy and colleagues that presented medium-term survival data . This single-center trial from Barcelona randomized patients to laparoscopic and open surgery for colon cancer and argued that laparoscopy was superior to open surgery in terms of postoperative morbidity, length of hospital stay, tumor recurrence, and cancer-related survival.
Overall survival was also found to be superior in an adjusted Cox model, but only trended towards significance in unadjusted data. Despite more modest long-term results  , this paper was undoubtedly seminal in shifting expert opinion regarding laparoscopy colon cancer surgery. Finally, we also argue that this transition was further promoted by the publication in of the COST trial, for which the influence was probably greatest in North America where this trial was funded and conducted . The above argument is further supported by the results of the cumulative meta-analysis for overall survival.
Indeed, the accumulation of survival data presented in figure 3b demonstrates that both the magnitude and precision of the survival HR has stabilized and remained essentially unchanged since publication of the COST trial 3-year data .
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In other words, both portions of the current study would indicate that laparoscopic surgery for colon cancer has been non-inferior to open surgery since , and that the surgical literature has been supportive of this finding since Taken together, these data provide a first example of pragmatic knowledge translation in surgery based on clinical trial evidence. Regarding rectal cancer surgery, it is not surprising that a notably weaker transition in expert opinion did not occur before , as neither the Lacy  nor COST  trials included any rectal cancer patients.
Although some surgeons may have extrapolated from the data on colon cancer, this is unlikely to have affected the prevailing expert opinion in the literature. Although survival data from this trial were not published until  , we argue that this publication together with mounting evidence of non-inferiority for laparoscopic colon cancer surgery began the transition for rectal cancer. That being said, since , only a fraction of patients enrolled in trials of laparoscopic and open surgery have done so for rectal cancer, and it likely that many experts in the field have continued to wait for the publication of further large scale trials addressing this topic.
Many surgeons argue that rectal cancer patients included in trials thus far have been carefully selected and have not been representative of challenging mid- to low-rectal lesions .