The doctors at Chevy Chase Surgical Associates are experienced surgeons who are focused on treating the whole patient and ensuring not only their successful healing but also a quick and lasting recovery.  Our doctors ensure this by being with our patients every step of the way.

Dr. Elizabeth O'Leary


Dr. Elizabeth O’Leary is an experienced General Surgeon.  She received her Bachelor of Arts degree in Biology and a Minor in Spanish from the College of St. Benedicts and received her Medical Degree with honors from the University of Minnesota School of Medicine.  She has been inducted into Phi Rho Sigma Medical Society where she served as President and also the Gold Humanism Honor Society.  She received her Master of Health Science degree at Johns Hopkins Bloomberg School of Public Health in Disease Control and Prevention and was awarded the Vaccine Science and Policy Graduate Certificate.  In the Department of Oncology at Johns Hopkins, Dr. O’Leary continued her research of cancer and was involved in many studies including the Human Papilloma Virus and its relationship to Head and Neck cancer and a trial of Herceptin in Squamous Cell Carcinoma of the Head and Neck.  Dr. O’Leary completed her surgical residency at the Medstar Washington Hospital Center, where she received an award for her research on breast cancer and received first place in a competition for her research creating a risk score for patients with Small Bowel Obstructions.  She has been recognized at both a national and regional level for her surgical research and has presented her research at the national meeting of the American College of Surgeons.


Dr. O’Leary has been a member of the American Society of Breast Surgeons, American College of Surgeons, the DC Chapter of the American College of Surgeons, the Georgetown Clinical Society, the American Medical Association, and the Montgomery County Medical Society.   For multiple years, Dr. O’Leary has been awarded Washingtonian Top Doctor and has received other prestigious awards as one of America’s Top Surgeons.  She is affiliated with Georgetown University Hospital as well as Sibley Memorial and Suburban Hospitals in the Johns Hopkins Medicine System.  She was actively involved with the Women’s Cancer Resource Center in program development for the WCRC & Sisters in Harmony.  She participated in a community-based initiative with emphasis on education and awareness and helped connect patients with cancer to the resources in the community.  


Dr. O’Leary most important role is taking care of her patients and providing a safe, reassuring place that will help them to easily navigate the sometimes confusing world of surgical diseases and cancer.  Her patients come first and her greatest reward is to be able to help a patient through their most trying times and get them to other side to bring a smile back to their hearts and faces.


Dr. O’Leary lives in Maryland with her husband and three children.  In her free time, she enjoys ballroom dancing, playing Cello, knitting, cooking, skiing and spending time with family.

Dr. Thomas Zorc


Dr. Zorc is a board certified general surgeon who has been in practice in Chevy Chase for over 20 years. He is a 1981 graduate of Georgetown University with a Bachelor of Science degree in Chemistry. He received his Doctorate in Medicine from the Georgetown University School of Medicine in 1985. He completed his surgical residency at Georgetown Hospital and the Washington Hospital Center in 1990. He is a fellow of the American College of Surgeons and is a member of the American Society of Breast Surgeons, the Society for Laparoendoscopic Surgery, and the American Medical Association. Dr. Zorc has been recognized by Washingtonian Magazine as one of the areas "Top Doctors" since 1999.

Dr. Marie Pennanen


Dr. Marie Pennanen, Director of the Chevy Chase Breast Center, is one of the most knowledgeable breast surgeons in the metropolitan Washington area. She has over twenty years of experience and has treated women from all over the world. Dr. Pennanen received her Bachelor of Science degree, magna cum laude, from Georgetown University and her Medical Degree with honors from New Jersey Medical School. She has been inducted into Phi Beta Kappa, Psi Chi (the international honor society in psychology) and Alpha Omega Alpha (the national medical honor society). She completed her surgical residency at George Washington University Medical Center where she received an award for research, and then joined the faculty at Georgetown University Medical Center and the Lombardi Cancer Center. As an Associate Professor of Surgery, she has been involved in research on the diagnosis, treatment and prevention of breast cancer, including ones supported by the prestigious National Cancer Institute. She is the author of numerous medical articles regarding breast cancer. She has received grants for her innovative programs which teach our next generation of doctors about comprehensive breast cancer care. Her passion is taking care of women with breast cancer, high risk for breast cancer or benign breast disease, one woman at a time, by providing state-of-the-art, personalized, compassionate care.


Dr. Pennanen is board certified by the American Board of Surgery and is a Fellow of the American College of Surgeons. She is a member of the American Society of Breast Surgeons. She is affiliated with Georgetown University Hospital, Sibley Memorial and Suburban Hospitals in the Johns Hopkins Medicine System, and George Washington University Hospital. She has been consistently recognized by her peers as one of Washington's Top Doctors in the field of Breast Surgery in Washingtonian magazine, and by her patients through the Patient's Choice Award. She is proud to be the 2012 Honoree of Living in Pink, a foundation dedicated to the search for a cure for breast cancer. In additional to giving lectures to the medical community, she has been featured on multiple television and radio programs related to breast cancer.


Dr. Pennanen and her husband live in Washington, DC with their four children. In her free time she enjoys spending time with her family, classical music concerts, hikes through Rock Creek Park and beyond, and baking Italian and Finnish family recipes.

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Dr. Seema Patel

Dr. Patel was born and raised in New York, where she attended Cornell University as an undergraduate student. She then moved to California and obtained a Master of Public Health degree from the University of California, Berkeley. Though she loved public health, she decided that, ultimately, she needed to become a doctor to be accomplish her goals. Her first goal, however, was to dedicate time to the underserved; therefore, she spent a year in rural Colorado (Fort Morgan, to be exact) working at a health care center through the AmeriCorps program. Dr. Patel then moved back to California and earned her M.D. degree from the University of California, Irvine. She returned to the East Coast and did residency in General Surgery at MedStar Washington Hospital Center. It was in DC that she met her husband and had their first child, a daughter. Further training took her to Orlando, Florida, where she completed a fellowship in Acute Care Surgery (a combination of Surgical Critical Care, Trauma Surgery, and Emergency General Surgery.) Dr. Patel then worked as an Acute Care Surgeon in Lakeland, Florida, for five years, during which time she had her second child, a son. Finally, she and her family returned to the Washington, DC area, and she proudly joined Chevy Chase Surgical Associates.

Dr. Patel is board-certified in General Surgery and Surgical Critical Care. She is a Fellow of the American College of Surgeons, and a member of the Association of Women Surgeons, Society of American Gastrointestinal and Endoscopic Surgeons, and the Eastern Association for the Surgery of Trauma.