[1] Univ Groningen, Univ Med Ctr Groningen, Dept Surg Oncol, Groningen, Netherlands
[2] Univ Groningen, Univ Med Ctr Groningen, Dept Radiat Oncol, Groningen, Netherlands
[3] Univ Groningen, Univ Med Ctr Groningen, Dept Radiotherapy, Groningen, Netherlands
[4] Univ Groningen, Univ Med Ctr Groningen, Dept Epidemiol, Groningen, Netherlands
[5] Univ Groningen, Univ Med Ctr Groningen, Dept Pathol, Groningen, Netherlands
[6] Univ Groningen, Univ Med Ctr Groningen, Dept Nucl Med & Mol Imaging, Groningen, Netherlands
[7] Univ Twente, MIRA Inst Biomed Technol & Tech Med, POB 217, NL-7500 AE Enschede, Netherlands