Prior to his appointment at MSKCC, he was Deputy Director for Extramural Sciences and Director of the Division of Cancer Treatment and Diagnosis at the National Cancer Institute, where he oversaw NCI's extramural clinical and basic research programs, including the evaluation of new therapeutics, diagnostics, and translational research.
He began his tenure with MSKCC in 1972 as a medical oncology fellow, rising over the next decade to Assistant Chief of its Solid Tumor Service.
As Physician-in-Chief at MSKCC beginning in 2002, Wittes presided over a period of extraordinary growth in both its clinical and research programs.
He also oversaw the construction of major new clinical facilities that have enhanced the center's programs in Surgery, Pathology, Pediatrics, Imaging, and the treatment of a full range of cancers.
Vincent Astor Chair of Clinical Research – July 17, 2003 to 2012 The Geoffrey Beene Cancer Research Center 2010 Progress Report, Page 3 Memorial Sloan-Kettering Cancer Center NIH Director’s Award – July 11, 2001 The National Institutes of Health Annual Director's Awards Ceremony 2001, Page 8 Public Health Service Distinguished Service Medal – June 22, 2000.