Survival outcomes according to the tumor location and prognostic factor in metastatic rectal cancer: a multicenter retrospective cohort study oleh Olcun Umit Unal, Olcun Umit Unal, Seval Akay, Huseyin Salih Semiz, Murat Keser, Gonul Demir, Zeliha Guzeloz Capar, Erkut Demirciler, Tugba Yavuzsen, Serkan Degirmencioglu, Bilgin Demir, Esin Oktay, Meltem Demirtas Gulmez, Mehmet Emin Arayici, Mehmet Emin Arayici