Dr. Gregory S. Sibley joins Virginia Cancer Specialists after serving as Radiation Oncologist and chair of the Cancer Committee at Sibley Memorial Hospital in Washington, D.C. for 14 years.  Throughout his career, Dr. Sibley has focused on providing the highest quality care in the field of radiation oncology. He has positioned himself as an expert in the multi-disciplinary treatment of cancer and in state-of-the-art radiation treatment planning techniques.