In many solid cancers, surgery remains a major part of treatment. In multidisciplinary treatment of these cancers, cure is not feasible without good local control, which is achieved often by surgery. To establish new treatment including surgery, surgical trials are essential. However, they are not easy due to the dilemma in high number of cases needed to provide adequate, statistical, sufficient power to detect differences and the feasibility of difficulty in maintaining quality control when the treatment is provided by numerous participating surgeons; this kind of trial remains challenge for surgical oncologists. The smaller the number of participating surgeons involved is, the easier is to ensure that high surgical standards are applied for the quality of surgery. However, as the number of the surgeons decreases, the accrual period increases and the results become less generalizable. The optimum approach to such trials would utilize a group of surgeons who can share the same surgical quality in terms of similar standards of safety, and efficacy is the only way to carry out this kind of trials. From several different types of experiences in surgical clinical trials, problems and possible solutions of surgical multicenter trials will be presented.