Santa Clarita Team

Dr. Callahan attended Yale University and obtained a BS in Biology. She later attended the University of Pennsylvania School of Medicine where she graduated with high honors, Alpha Omega Alpha. She completed her Internal Medicine and Hematology/Oncology training at UCLA.
As an assistant clinical professor of medicine at UCLA, Dr. Rena Callahan is active in the breast cancer research and treatment program. She has spoken on the topic of the evolving treatment of breast cancer at both local and national meetings.
Dr. Callahan is dedicated to providing patient centered care. She shares in decision making with patients so that this individual goals are met. She has a unique interest in how complementary therapies, such as meditation, yoga, and reiki can be integrated with Western evidence-based medicine.

Dr. Gregory Senofsky is a board-certified, fellowship-trained surgical oncologist with special expertise in breast and melanoma surgery. He sees patients for consultations in Santa Clarita, Porter Ranch and Encino, and performs surgery at nearby community hospitals and at Ronald Reagan UCLA Medical Center.

Dr. Nimit Sudan is a hematologist oncologist who practices in Encino and Santa Clarita. He is board certified in internal medicine, hematology and medical oncology, and is an assistant clinical professor in the David Geffen School of Medicine at UCLA.