Eastern Long Island Hematology Oncology, PC . 1333 E Main Street, Riverhead, NY . BOOK Save. Save. Diane M. Clausen, MD. DianeClausen.MD.com • Hematologist / Oncologist • 31 years experience North Shore Hematology Oncology Associates PC . 235 N Belle Mead Avenue, East Setauket, NY 11733 ..