Dr. Martin S. Weiser

Dr. Martin R. Weiser, MD, is an internationally recognized colorectal surgeon specializing in the surgical management of gastrointestinal malignancies. He holds the Stuart H.Q. Quan Chair in Colorectal Surgery at Memorial Sloan Kettering Cancer Center, where he also serves as Vice Chair for Faculty Affairs in the Department of Surgery. Dr. Weiser earned his medical degree from the University of Chicago Pritzker School of Medicine, followed by a residency in general surgery at Brigham and Women’s Hospital. He completed fellowships in surgical oncology at Memorial Sloan Kettering and colon and rectal surgery at Mount Sinai Medical Center. Board-certified in both General Surgery and Colon & Rectal Surgery, he is widely regarded for his precision in treating cancers of the colon, rectum, anus, appendix, and small intestine.

Dr. Weiser is renowned for his expertise in minimally invasive and nerve-sparing surgical techniques, including laparoscopic and robotic approaches that aim to preserve bowel, bladder, and sexual function. He leads the surgical arm of the international PROSPECT trial, which aims to personalize rectal cancer treatment and reduce overtreatment by identifying patients who can safely avoid radiation therapy. As director of Memorial Sloan Kettering’s colorectal cancer database, Dr. Weiser has been instrumental in developing clinical tools that integrate molecular and pathological data to enhance staging accuracy and inform treatment decisions. His laboratory investigates the biological mechanisms of tumor spread, and his research has resulted in over 250 peer-reviewed publications that have helped shape contemporary colorectal cancer care.

In addition to his clinical and research contributions, Dr. Weiser is a respected educator and academic leader. He serves on the editorial boards of several prominent journals, including the Journal of Clinical Oncology and Annals of Surgical Oncology, and is section editor for colorectal surgery in UpToDate. He plays an active role in national cancer guideline development through his work with the American Joint Committee on Cancer and other professional societies. Frequently recognized for his excellence in patient care, he has been named a Castle Connolly Top Doctor and is consistently listed among New York Magazine’s Best Doctors. Through his dedication to surgical innovation, translational research, and mentorship, Dr. Weiser continues to advance the field of colorectal oncology.