Ram S. Trehan started Greater Washington Oncology Associates in 1990 after completion of his fellowship in Hematology and Oncology from The Washington hospital Center. He has been practice in the Suburban Maryland area as well as Washington D.C. and at present heads the group of five Board Certified Medical Oncologists/Hematologists.

Dr. Trehan held a very active position at Holy Cross Hospital having been the President of the Medical Staff and currently as the Secretary Treasurer of the Holy Cross Hospital Board of Trustees. He has headed multiple initiatives for the indigent and participates regularly in community benefit programs of the hospital and providing healthcare and oncology care to all people in respective to their paying status. Dr. Trehan sees patients in Silver Spring, Rockville and Germantown Offices five days a week and also at Riderwood Community in Silver Spring.