Dr. Andrew D. Seidman

Dr. Andrew D. Seidman, MD, is a highly experienced medical oncologist who has spent three decades specializing in the treatment of breast cancer at Memorial Sloan Kettering Cancer Center (MSK). He treats all subtypes and stages of breast cancer, from earliest diagnosis to the most advanced disease, and has developed particular expertise in the management of breast cancer that has metastasized to the brain, a condition historically addressed primarily by radiation oncologists and neurosurgeons. Seeing more than 1,000 patients annually through both in-person and remote visits, Dr. Seidman is committed to providing expert, evidence-based guidance alongside compassionate, humane care. His path to oncology was shaped by meaningful patient experiences during his internal medicine residency, early exposure to outpatient oncology practice, and the influence of strong mentors who helped him recognize the field's extraordinary demands and rewards.

Dr. Seidman's research has focused on studying new chemotherapeutic agents and targeted therapies for metastatic breast cancer, with a particular emphasis over the past decade on improving outcomes for patients with brain metastases. He has designed and led phase 1, 2, and 3 clinical trials, contributing to a broader shift in oncology away from conventional toxic chemotherapy toward targeted treatments with fewer side effects. His ongoing interdisciplinary work with colleagues at MSK and beyond is expected to influence future treatment approaches for this challenging patient population. Over his career, he has been an active participant in the rapid advances in understanding breast cancer biology that have driven steady improvements in patient outcomes over the past 30 years.

Beyond his clinical and research responsibilities, Dr. Seidman is deeply attentive to the emotional and informational needs of patients and their families, recognizing that the volume of information available online can often feel overwhelming. He works to provide clarity, hope, and realistic reassurance, supported by a skilled multidisciplinary team. Outside of medicine, he maintains an active personal life that includes biking, hiking, skiing, gardening, baking, reading, and organizing a book club that meets quarterly. He values time with family and brings the same energy and enthusiasm to his personal pursuits as he does to his work in oncology.