1082 Fig. 4 a Comparison of overall survival of patients with colon cancer (all stages). b Comparison of overall survival of patients with stage I colon cancer. c Comparison of overall survival of patients with stage II colon cancer. d Comparison of overall survival of patients with stage III colon cancer p= 0.132 p= 0.743 Laparoscopic Open Laparoscopic Open Int J Colorectal Dis (2012) 27:1077–1085 Laparoscopic Open Laparoscopic Open p= 0.045 p= 0.072 hospital stay were demonstrated in most randomized con- trolled trials [3–6]. The current study showed that laparoscopic surgery not only improved the short-term outcomes of patients with colorectal cancer, but it also led to lower postoperative morbidity and mortality as well as improvement in both overall and cancer specific survivals in a center with a high volume of cases. Despite improvement in many parameters, which assessed postoperative outcomes, most individual trials were unable to demonstrate a reduction in complica- tion rate or mortality. Nevertheless, a significant reduction in mortality rate and a trend towards a lower morbidity could be demonstrated in a meta-analysis [16]. Moreover, a lower complication rate was shown in population studies which included a large number of patients [17]. The inabil- ity to demonstrate improvement in most randomized trials might be due to the fact that the trials were not powered to show the difference. In clinical practice, both in the com- munity as well as individual center with a large number of patients, laparoscopic surgery helped to reduce the compli- cation rate. Another reason for not able to demonstrate a lower complication rate following laparoscopic surgery is likely due to the high conversion rates most of the published trials. We believe that a low conversion rate is important to generate the benefit of laparoscopic surgery as most of the studies are analyzed with the intention to treat principle. There are controversies on whether conversion is associated with poor outcome. In the CLASICC trial, the conversion was associated with worse outcome when compared with open operation [6]. Other studies showed that the outcome was not worse with open operation [18, 19]. However, in cases of conversion, the outcome would at best be similar to open resection and the benefit of operation regarding the cardiopulmonary complications, ileus and wound complica- tion of laparoscopic surgery cannot be derived. Lacy et al. demonstrated fewer complications and better survival in patients with laparoscopic resection and the presence of a low conversion rate is important to obtain the beneficial results [3]. The survival is the most important outcome to assess treatment success for malignant disease. In colorectal can- cer, both the overall survival and cancer specific survival are