Ovarian cancer is particularly dangerous because its presence is difficult to detect until it has spread beyond the ovaries. Update Date: 06/10/2008James R. Mason, MD, Oncologist, Director, Blood and Marrow Transplantation Program and Stem Cell Processing Lab, Scripps Clinic, Torrey Pines, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.