Long term clinical outcomes and associated predictors of progression free survival in anal canal cancer - Beltrán Ponce, Sara E.; Erickson, Beth A.; Hall, William A.; Bedi, Meena; Martens, Michael J.; Siker, Malika; Thomas, James; George, Ben; Ludwig, Kirk; Peterson, Carrie; Ridolfi, Timothy; Longo, John M. (Journal of Gastrointestinal Oncology, 2022)