Dr. Gregory Tiesi was named Medical Director of Hepatobiliary Surgery at the Jersey Shore University Medical Center, Hackensack Meridian Health in 2022. He was previously a Surgical Oncologist at the Helen F. Graham Cancer Center & Research Institute at ChristianaCare. He is board certified in both Complex General Surgical Oncology and General Surgery. He completed a General Surgery residency at Rutgers-New Jersey Medical School and a research fellowship focused on Peritoneal Malignancies/Hyperthermic Intraperitoneal Chemotherapy (HIPEC). This was followed by a fellowship in Complex General Surgical Oncology at the University of Miami. He holds a fellowship from the American College of Surgeons.

Dr. Tiesi has a diverse surgical oncology practice that includes treatment of liver, pancreas, gallbladder, intestinal, colon, esophageal and stomach cancers, as well as melanoma, sarcoma, peritoneal and neuroendocrine tumors. He also maintains a very active practice in endocrine and head and neck diseases such as thyroid, parathyroid and adrenal diseases/cancers. 

He is a Clinical Instructor at the Sidney Kimmel Medical College, part of the Thomas Jefferson University, and Clinical Assistant Professor at the Philadelphia College of Osteopathic Medicine. He was previously head of the Surgical Oncology Research Fellowship at the Helen F. Graham Cancer Center, has published several peer reviewed articles and has presented his research at multiple national and international meetings.

Dr. Tiesi has earned many accolades throughout his career such as the Golden Apple Award, the Arnold P. Gold Foundation Award for Humanism (twice), the Alfred S. Ketchum, MD Award and he was inducted into the Alpha Omega Alpha Honor Medical Society, Beta Chapter. Most recently, he received the Christiana Care Rising Star Award and was selected by his peers and Delaware Today Magazine as a Top Doctor in Surgical Oncology.