[1] Leiden Univ, Dept Surg, Med Ctr, K6-R,POB 9600, Leiden, Netherlands
[2] Leiden Univ, Dept Oncol, Med Ctr, Leiden, Netherlands
[3] Leiden Univ, Dept Gerontol & Geriatr, Med Ctr, Leiden, Netherlands
[4] Aarhus Univ Hosp, Dept Surg, Aarhus, Denmark
[5] Danish Colorectal Canc Grp DCCG Dk, Copenhagen, Denmark
[6] Belgian Canc Registry, Brussels, Belgium
[7] Oslo Univ Hosp, Dept Oncol, Oslo, Norway
[8] Oslo Univ Hosp, KG Jebsen Colorectal Canc Res Ctr, Oslo, Norway
[9] Otto von Guericke Univ, Inst Qual Assurance Operat Med Ltd, Magdeburg, Germany
[10] Elisabeth Hosp, Dept Gen & Visceral Surg, Kassel, Germany
[11] Karolinska Inst, Dept Mol Med & Surg, Stockholm, Sweden
[12] Umea Univ, Dept Radiat Sci, Oncol, Umea, Sweden
[13] Norwegian Univ Sci & Technol, Dept Canc Res & Mol Med, NTNU, Trondheim, Norway
[14] Canc Registry Norway, Oslo, Norway