Acknowledgments
Apart from the authors, the following persons were involved in working out the study protocol: Ulf Gunnarsson, Lars Lundell and Per-Olov Nyström, Department of Surgery, Karolinska Institutet, Huddinge, Per Sandström, Department of Surgery and Hans Starkhammar, Department of Oncology, University Hospital, Linköping, Sweden. This study was funded by the Medical Research Council of Southeast Sweden
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.