Patterns of failure and survival for nonoperative treatment of stage c0 distal rectal cancer following neoadjuvant chemoradiation therapy - Habr Gama, Angelita; Perez, Rodrigo O.; Proscurshim, Igor; Campos, Fabio G.; Nadalin, Wladimir; Kiss, Desiderio; Gama-Rodrigues, Joaquim José (Journal of Gastrointestinal Surgery, 2006)