Shirish A. Mahajan, M.D., Hematology and Oncology. Dr. Mahajan first came to the Rideout Cancer Center in August of 2011. He completed his residency in Internal Medicine at the State University of New York, in Stony Brook, New York. Dr. Mahajan wa Board Certified by the American Board of Internal Medicine, August 1997, Medical Oncology, November 2000, and Board Certified by the American Board of Hematology in November 2004. His hospital appointments include Rideout Memorial Hospital, Fremont Medical Center and University of California, Davis.