Meet Martin Weiser: Colorectal Surgeon at MSK

Dr. Martin Weiser treats colon, rectal, anal and appendix cancers using minimally invasive, nerve-sparing surgeries that preserve bowel, bladder, and sexual function.
Video Details
 Memorial Sloan Kettering surgical oncologist Martin Weiser

Martin R. Weiser, MD

Colorectal Surgeon

Areas of Expertise

Conditions I Treat

  • Rectal cancer
  • Colon cancer
  • Anal cancer

My Specialties

  • Minimally invasive surgery
  • Robotic surgery
  • Laparoscopic surgery
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Dr. Weiser's Office Information
Languages: English
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Get to Know Me

I’m a surgical oncologist and colorectal surgeon who treats cancers of the gastrointestinal tract. This includes, rectal cancer, colon cancer, anal cancer, small bowel cancers, gastrointestinal neuroendocrine tumors and appendiceal cancer. I treat new tumors as well as tumors that have spread (metastatic tumors), or come back after treatment.

I’m an expert in minimally invasive surgery, including laparoscopic and robotic surgery. These methods allow me to remove tumors using smaller incisions and with less pain and faster recovery. When possible, I use nerve-sparing techniques during surgery that protect sphincter, bladder, and sexual function.

I believe in a personal approach to patient care. Our advanced practice providers, nurses, and staff pay close attention to each patient’s needs. We adopt a team approach and work closely with radiation oncologists, medical oncologists, and other specialists. Our team of experts meet weekly to discuss each patient’s diagnosis and treatment. This teamwork helps us give patients the most complete and thoughtful care possible. 

I currently serve as Chair of the Department of Surgery at Memorial Sloan Kettering Cancer Center (MSK). My vision is to redefine the role of surgery in a new era of cancer care. 

As chair of the department, I’m focused on four strategic priorities. First, we are advancing precision surgery by integrating technologies such as artificial intelligence to deliver more personalized surgical care. Second, we are expanding translational research that bridges discoveries in the laboratory with innovations in the operating room. Third, we are training the next generation of surgical leaders who will advance cancer care around the world. Finally, we are investing in the people, infrastructure, and resources that drive innovation. Together, these priorities will ensure that MSK continues to set the global standard for surgical oncology.

My clinical research aims to improve the accuracy of tumor staging so we can better predict treatment results after cancer surgery. I also continue to refine MSK’s colorectal cancer database. This database helps assess patient outcomes, advance clinical research, and improve quality of care for people with colorectal cancer.

My lab studies the biology of cancer metastasis, which is how and why cancer spreads. We also study why some cancers resist treatment and the unique biology of mismatch repair–deficient colorectal cancer. We use these insights to develop better therapies and new technologies. This includes blood-based tests that detect and quantify circulating tumor DNA so we can diagnose, monitor, and treat cancer more effectively.

I have served as surgical lead for PROSPECT, an international trial, which showed that some rectal cancer patients can safely avoid radiation. I also served as surgical lead for a trial led by Dr. Andrea Cercek. This trial tested whether the immunotherapy drug, dostarlimab, could treat rectal cancer without the need for surgery. We are continuing this work through follow up clinical trials.

I have held many leadership roles in the past, including serving as MSK’s Medical Staff President. I also serve on the National Cancer Institute’s Rectal-Anal Task Force. This expert panel helps design future clinical trials for people with rectal cancer. Over my career, I have published more than 300 articles, book chapters, and reviews on robotic surgery, cancer biology, rare tumors, cancer staging, and tumor metastasis. I also lecture around the world on colorectal, anal, and appendiceal cancers, and on advances in minimally invasive surgery.

What I Do at MSK

I'm a colorectal (KOH-loh-REK-tul) surgeon, which is a doctor with special training in surgery on the colon and rectum.

  • Chair, Department of Surgery
  • Murray F. Brennan Endowed Chair in Surgical Oncology
Areas of Expertise

Conditions I Treat

  • Rectal cancer
  • Colon cancer
  • Anal cancer
  • Appendiceal (appendix) cancer and conditions
  • Gastrointestinal neuroendocrine tumors

My Specialties

  • Minimally invasive surgery
  • Robotic surgery
  • Laparoscopic surgery
  • Nerve-sparing surgery
  • Preserving bowel, bladder, and sexual function
  • Clinical trials
This list shows some key areas of focus, but it may not cover all expertise. When making an appointment, you will be matched with the best healthcare provider for your needs.
Education & Honors

Education

  • MD, University of Chicago

Residencies

  • General Surgery, Brigham and Women's Hospital

Fellowships

  • Surgical Oncology, Memorial Sloan Kettering Cancer Center
  • Colon and Rectal Surgery, Mount Sinai Medical Center

Board Certifications

  • Surgery
  • Colon and Rectal Surgery

Awards and Honors

  • Castle Connolly: America’s Top Doctor (2023-2026)
  • Newsweek: America’s Leading Doctors in Colorectal Surgery (2025)
  • Top Doctors New York Metro Area, Castle Connolly (2012-2020, 2023)
  • Castle Connolly: New York Magazine Top Doctors (2012-2025)
  • Willet F. Whitmore Award for Clinical Excellence, MSK (2023)

Insurance Information

Understanding your insurance options is an important part of managing your cancer care. We have relationships with many common healthcare providers and plans.

Learn more about the insurance plans that participate with MSK.

If you don't have health insurance or are worried that your care may not be fully covered, our financial assistance programs may be able to help.

Health plans can change at any time. Call the number on the back of your insurance card to see what your plan covers. Make sure it covers the MSK location where you’ll get care.

If you have questions about insurance, call us at 646-497-9176.

Make an Appointment

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New Patients
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Current Patients
Request an appointment by calling your Care Team or messaging them in MSK MyChart.

Contact and Location

Office Phone
Location
New York, NY
Rockefeller Outpatient Pavilion
160 East 53rd Street New York NY 10022
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Looking to see a doctor at a different location? See all MSK locations.

Colleagues

Doctors at Memorial Sloan Kettering work as teams, with specialists from all different areas. This allows us to consider all your needs together, and to give you the best possible care.

See all Biobanking doctors

See all Surgery doctors

See all Colorectal Service doctors

Clinical Trials

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Find a Clinical Trial for You

Memorial Sloan Kettering's doctors and scientists are constantly developing new treatments for cancer. MSK is typically running hundreds of clinical trials at a given time.

You may be able to participate in a clinical trial even if you are new to MSK. Search our online directory to find trial information and see more about who can participate.

Search clinical trials

Research and Publications

View Dr. Weiser's Lab

Selected Book Chapters

Weiser MR and Saltz LB. Chapter 44 Adenocarcinoma of the Colon and Rectum. In Scientific American Surgery. 2015

Patel S and Weiser MR. Robotic Rectal Surgery. In Rectal Cancer: Modern Approaches to Treatment (Chang et al, editors) 2016

Pappou M and Weiser MR. Proctectomy. In The ASCRS Textbook of Colon and Rectal Surgery. 2016.

Weiser MR. Robotic Right Hemicolectomy. SAGES Manual. 2017

Pappou M and Weiser MR. Total Mesorectal Excision. In Textbook of Surgical Oncology 2016

Weiser MR. Open, Laparoscopic, and Robotic Right Hemicolectomy for Cancer. Mastery of Surgery. 2017

Fedler S and Weiser MR. Pelvic Exenteration. In Colon and Rectal Surgery: Abdominal Operations 2nd Ed. 2017.

Langan R and Weiser MR. Stage IV Colorectal Cancer. In Clinical Decision Making in Colorectal Surgery, 2nd edition, edited by Dr. Scott Steele, Justin Maykel, and Steven D. Wexner. Springer Science and Business Media. 2017

Weiser MR and Garcia-Aguilar J Basic Principles of the Operative Treatment of Colorectal Cancer In: Yeo CJ, ed. Shackelford’s Surgery of the Alimentary Tract, 8th edition. Elsevier; 2018.

Weiser MR. Perspective on colorectal neoplasms. In Zinner M and Ashley S (ed.), Maingot’s Abdominal Operations, 13th ed., in press. McGraw-Hill, New York.

Kleiman DA, Weiser MR. 2018. Locally advanced rectal cancer. In Hochwald SN and Cance WG (ed.), Complex General Surgical Oncology. Decker, Toronto. https://www.deckerip.com/products/cgso/

Publications on PubMed

Visit PubMed for a full listing of Dr. Weiser’s journal articles. Pubmed is an online index of research papers and other articles from the US National Library of Medicine and the National Institutes of Health.

See all on PubMed

Disclosures

Members of the MSK Community often work with pharmaceutical, device, biotechnology, and life sciences companies, and other organizations outside of MSK, to find safe and effective cancer treatments, to improve patient care, and to educate the health care community. These activities outside of MSK further our mission, provide productive collaborations, and promote the practical application of scientific discoveries.

MSK requires doctors, faculty members, and leaders to report (“disclose”) the relationships and financial interests they have with external entities. As a commitment to transparency with our community, we make that information available to the public. Not all disclosed interests and relationships present conflicts of interest. MSK reviews all disclosed interests and relationships to assess whether a conflict of interest exists and whether formal COI management is needed.

Martin R. Weiser discloses the following relationships and financial interests:

  • UptoDate
    Intellectual Property Rights; Professional Services and Activities

If you’re a patient at MSK and would like more information about your doctor’s external relationships, please talk with your doctor.

The information published here is a complement to other publicly reported data and is for a specific annual disclosure period. There may be differences between information on this and other public sites as a result of different reporting periods and/or the various ways relationships and financial interests are categorized by organizations that publish such data.

This page and data include information for a specific MSK annual disclosure period (January 1, 2024 through disclosure submission in spring 2025). This data reflects interests that may or may not still exist. This data is updated annually.

Learn more about MSK’s COI policies here. For questions regarding MSK’s COI-related policies and procedures, email MSK’s Compliance Office at [email protected].


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