[1] MedStar Georgetown Univ Hosp, Washington, DC USA
[2] MedStar Georgetown Univ Hosp, Lombardi Canc Ctr, Washington, DC USA
[3] Georgetown Univ, Ruesch Ctr Cure Gastrointestinal Canc, Lombardi Comprehens Canc Ctr, Washington, DC USA
[4] MedStar Washington Hosp Ctr, Washington, DC USA
[5] Georgetown Univ, Dept Biostat Bioinformat & Biomath, Washington, DC USA