[1] Univ Basel Hosp, Dept Surg, CH-4031 Basel, Switzerland
[2] Cantonal Hosp Olten, Dept Surg, Olten, Switzerland
[3] Cantonal Hosp St Gallen, Div Hematol & Oncol, St Gallen, Switzerland
[4] Viollier AG, Histopathol Cytol, Basel, Switzerland
[5] Heidelberg Univ, Inst Med Biometry & Informat, Heidelberg, Germany
[6] Cantonal Hosp St Gallen, Dept Surg, St Gallen, Switzerland