Dr. Marks is a colorectal surgeon, researcher, and educator who is internationally recognized for achieving unsurpassed colorectal cancer treatment outcomes and seeking the highest quality-of-life for patients with cancer and other colorectal conditions. The cornerstones of his approach are multimodal therapy, surgical techniques that preserve the anal sphincter and are minimally invasive, and for select cases, a program of no immediate surgery. By 2009, he reached the milestone of performing 1,000 laparoscopic colorectal operations. Dr. Marks developed a laparoscopic method for performing a novel transanal-transabdominal proctectomy (TATA) procedure first described by his father as a strategy for sphincter preservation even in very low and bulky rectal cancers. He went on to devise a way to complete the rectal portion of the operation through the anal canal which enabled a reduction of the number of abdominal ports (transanal total mesorectal excision). He was an early adopter of Transanal Endoscopic Microsurgery (TEM), an operative platform that enables local excision of tumors under direct visualization through the anal canal, making tumors even high in the rectum accessible through the anus and avoiding removal of the entire rectum. More recently, as the first US site engaged in an ongoing Phase II Clinical Trial of the single port robot (Intuitive), he currently has the world's largest experience with single-port robot abdominal and transanal colorectal operations. He also has the world’s largest experience working with Mini Robots in FDA-approved trials.

Dr. Marks’s academic commitment is evident not just in his clinical research and innovation. Twenty years ago he piloted a Minimally Invasive Colorectal Surgery and Advanced Rectal Cancer Fellowship that is still one of only four such programs in the United States. His educational commitment also includes being a laparoscopic and robotic colorectal training center. He is training the next generation of surgical thought leaders in the US and abroad in these programs and through international and organizational involvement. He established the Multidisciplinary International Rectal Cancer Society in 2012 which convenes worldwide rectal cancer experts for an International Rectal Cancer Symposium biannually to exchange ideas and inspire one another. He is also president of the International Society of Laparoscopic and Colorectal Surgeons. Dr. Marks is especially honored to be a member of the Executive Committee of the American College of Surgeons National Accreditation Program for Rectal Cancer, which sets standards for rectal cancer care drawing on the experience he, other American, and international colleagues helped demonstrate. As co-chair of the SAGES Oncology Taskforce, he champions the wider adoption of minimally invasive surgical approaches by surgeons who operate on cancers in other organ systems.

By far, he considers his biggest accomplishments to be those of his family: daughter Lizzie bachelor’s in Mathematics at Barnard College of Columbia University (2023), son Will Harvard Law School (2024), and daughter Victoria Yale School of Medicine (2026). He’s ever grateful to his wife Meredith—lawyer, mom, saint, and companion extraordinaire.