In 1940, Rhoads was selected as director of Memorial Hospital, which was devoted to cancer care and research, and had recently moved into a new building. Rhoads was selected for his interest in clinical investigation in addition to laboratory research, as the hospital did research as well as treatment. He succeeded James Ewing, a noted oncologist. Ewing had written about cancer transplantation in 1931, a subject which Rhoads had referred to in his scandalous letter written in November of that year. In 1941 Rhoads was studying the use of radiation to treat leukemia.