A total of 66 published articles of RCTs comparing laparoscopically assisted and open surgery for colon cancer were identiﬁed. Of these trials, there were 19 articles just with short-term outcomes available and another 17 articles with regard to the colorectal cancer. In addition, 21 articles had not reported relevant information. So there were 9 potential articles left to further review. Of these trials, 4 studies were excluded because there were less than 100 patients included[10-13
]. Two studies were reported at a different time. So finally 3 studies involving 2147 patients reported long-term outcome data and were included in the analysis. All of the included studies were published as full articles. Baseline characteristics of included studies are described in Table . Quality assessment revealed that all studies were of good or moderate quality (Table ), indicating that all studies were of reasonable methodological quality; none of the studies had any “fatal” methodological flaws.
Characteristics of included studies (laparoscopic vs open group)
Quality assessment: internal validity of the included randomized trials
In 2009, the COLOR trial[14
] published its long-term outcomes after laparoscopic surgery vs
open surgery. 1076 patients were eligible for analysis (542 assigned open surgery and 534 assigned laparoscopic surgery). Median follow-up was 53 mo (range 0.03-60). The combined 3-year disease-free survival for all stages was 74.2% in the laparoscopic group and 76.2% in the open surgery group (P
= 0.70). The hazard ratio (HR) for disease-free survival (open vs
laparoscopic surgery) was 0.92 (95% CI: 0.74-1.15). The combined 3-year overall survival for all stages was 81.8% in the laparoscopic group and 84.2% in the open-surgery group (P
In 2008, Lacy et al[15
] reported the long-term results of a randomized clinical trial of laparoscopy-assisted vs
open surgery (LAC vs
OC) for colon cancer. Two hundred and nineteen patients entered the study. The median follow-up was 95 mo. There was a tendency towards higher cancer-related survival (P
= 0.07, NS) and overall survival (P
= 0.06, NS) for the LAC group. The regression analysis showed that LAC was independently associated with a reduced risk of tumor relapse (hazard ratio 0.47, 95% CI: 0.23-0.94), death from a cancer-related cause (0.44, 0.21-0.92) and death from any cause (0.59, 0.35-0.98). So they concluded that LAC is more effective than OC in the treatment of colon cancer. In 2002, Lacy et al[5
] reported the same study with a median length of follow-up of 43 mo, demonstrating that LAC was more effective for treatment of colon cancer in terms of morbidity, hospital stay, tumor recurrence, and cancer-related survival.
In 2007, Fleshman et al[16
] published the 5-year data from the COST study group trial. Patients were followed a median of 7 years. Disease-free 5-year survival (OC 68.4%, LAC 69.2%, P
= 0.94) and overall 5-year survival (OC 74.6%, LAC 76.4%, P
= 0.93) were similar for the 2 groups. Overall recurrence rates were similar for the 2 groups (OC 21.8%, LAC 19.4%, P
= 0.25). These recurrences were distributed similarly between the 2 treatment groups. Sites of ﬁrst recurrence were distributed similarly between the treatment arms (OC: wound 0.5%, liver 5.8%, lung 4.6%, other 8.4%; LAC: wound 0.9%, liver 5.5%, lung 4.6%, other 6.1%). Likewise, in 2004, the three-year outcomes of COST[17
] were also reported with the recurrence rate and the overall survival being similar for the two groups. So they concluded that laparoscopic colectomy for curable colon cancer is not inferior to open surgery based on oncologic endpoints.
Overall mortality and cancer-related mortality
All 3 studies reported overall mortality at maximum follow-up. 2147 patients were included in this meta-analysis. The overall mortality was similar in the two groups (24.9%, 268/1075 in the laparoscopic group and 26.4%, 283/1072 in the open group). No significant differences between laparoscopic and open surgery were found in overall mortality during the follow-up period of the study [OR (fixed) 0.92, 95% CI: 0.76-1.12, P = 0.41] (Figure ). Regarding the cancer-related mortality, only Lacy’s study reported this result (16%, 17/106 in laparoscopic group and 27%, 28/102 in open group, P = 0.07, NS).
Meta-analysis on overall mortality (A), overall recurrence (B), local recurrence (C) and distant recurrence (D) at maximum follow-up.
Overall 5-year disease-free survival and overall 5-year survival
Both COLOR and COST trials reported the overall 5-year disease-free survival and overall 5-year survival between laparoscopic and open groups. In the COLOR trial, the overall 5-year disease-free survival and overall 5-year survival were 66.5% vs 67.9% and 73.8% vs 74.2%, respectively; in the COST trial, the overall 5-year disease-free survival and overall 5-year survival were 69.2% vs 68.4% and 76.4% vs 74.6%, respectively. As seen in the two large randomized trials, these two outcomes were similar between the two groups.
Overall and local and distant recurrence
All 3 studies reported these outcomes. No signiﬁcant difference in the development of overall recurrence was found in colon cancer patients, when comparing laparoscopic and open surgery [2147 pts, 19.3% vs 20.0%; OR (ﬁxed) 0.96, 95% CI: 0.78-1.19, P = 0.71] (Figure ). The number of patients that developed a local recurrence at the maximum follow-up of the study was similar after laparoscopic and open surgery, showing that there is no significant difference between laparoscopic and open procedures [2147 pts, 4.0% vs 4.4%; OR (ﬁxed) 0.91, 95% CI: 0.59-1.39. P = 0.66] (Figure ). Similarly, no significant difference in the development of distant metastases was found in colon cancer patients, when comparing laparoscopic and open surgery [2147 pts, 12.8% vs 14.0%; OR (ﬁxed) 0.90, 95% CI: 0.70-1.16, P = 0.41] (Figure ).