[1] Univ Med Ctr Goettingen, Gottingen, Germany
[2] Georg August Univ, Univ Med Ctr, Dept Med Stat, Gottingen, Germany
[3] Friedrich Alexander Univ Erlangen Nurnberg, Univ Klinikum Erlangen, Dept Radiat Oncol, Erlangen, Germany
[4] Klinikum Oldenburg, Oldenburg, Germany
[5] Univ Med Ctr Erlangen, Dept Surg, Erlangen, Germany
[6] Georg August Univ, Univ Med Ctr, Dept Gen Visceral & Pediat Surg, Gottingen, Germany
[7] Goethe Univ Frankfurt, Dept Radiotherapy & Oncol, Frankfurt, Germany
[8] Univ Med Ctr, Gen Visceral & Pediat Surg, Gottingen, Germany