Martin R. Weiser, MD
Vice Chair for Education and Faculty Development, Department of Surgery; Stuart H.Q. Quan Chair in Colorectal Surgery
Colon and Rectal Cancer Surgery; Anal Cancer; Appendiceal Cancer; Minimally Invasive Surgery
New Patient Appointments
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Dr. Weiser accepts the following list of insurance providers. Select your insurance provider to see more details.
Memorial Sloan Kettering is an in-network provider with Aetna HMO, POS, and PPO plans. Aetna does not include us in any of the plans you can purchase through the insurance exchanges or through Medicare. Please ask your insurance if you need a one-time referral. MSK has an agreement with the Aetna Transplant Program for all Aetna's commercial products.
In New York State
Memorial Sloan Kettering is an in-network provider with Empire Blue Cross Blue Shield (Wellpoint) of New York HMO, EPO, PPO, and POS plans, with the following exceptions:
- Empire Blue Cross Blue Shield does not include us in any of the plans you can buy through the insurance exchanges.
- Memorial Sloan Kettering is not an in-network provider for Empire's Medicare Managed Care plan known as Mediblue).
- Memorial Sloan Kettering is a designated Center of Excellence by Blue Cross Blue Shield.
In New Jersey
Memorial Sloan Kettering is an in-network provider with some Horizon Blue Cross Blue Shield of New Jersey plans for individuals, families, and small businesses. For example, the PPO plan is in-network with our Manhattan locations.
Horizon Blue Cross HMO is only in-network with our Basking Ridge, Bergen and Monmouth locations. It does not allow access to our Manhattan facilities.
Horizon Blue Cross PPO is in network with our Basking Ridge, Bergen, Monmouth and Manhattan locations.
OMNIA Plans: Tier I EPO based plan policy is only in-network with our Basking Ridge, Bergen and Monmouth locations and does not allow access to our Manhattan sites. Tier II EPO is only in-network with our Manhattan sites if it is a blue-card plan (there would be a suitcase logo indicating PPO on the front of the card).
Other plans may only be in-network at our Basking Ridge, Bergen or Monmouth locations.
Outside New York State and New Jersey
Some, but not all, Blue Cross Blue Shield plans outside of New York and New Jersey include Memorial Sloan Kettering as an in-network provider. Contact your insurance to find out if your plan provides in-network access to Memorial Sloan Kettering.
We understand that there may be many complexities involved with insurance coverage purchased through the health exchange network of the Affordable Care Act. We’re here to help. If you have questions about how your care will be covered by an insurance provider, or need help navigating a change in coverage, please call us at 646-227-3378; if you are not a resident of New York, you can call us at 866-248-1274. Our team is here to listen to your concerns and assist you in any way we can. We want our care to be as accessible and affordable for as many people as possible.
Memorial Sloan Kettering is an in-network provider with CIGNA's HMO, POS, and PPO plans. CIGNA does not include us in any of the plans you can buy through the insurance exchanges.
- If you are a New York State resident: Please ask your insurance if you need a one-time referral.
- If you live outside of New York State: Please ask your insurance if you have in-network access to Memorial Sloan Kettering.
Memorial Sloan Kettering is an in-network provider with EmblemHealth’s PPO, EPO, POS, HMO plans and Medicare plans. Emblem Health does not include us in any of its Select Care network plans. EmblemHealth includes GHI, HIP, Vytra, and ConnecticCare (in NYS Only). You must bring a referral from your Emblem primary care doctor to your first appointment.
Memorial Sloan Kettering is an in-network provider with HealthFirst’s commercial products; these commercial products are not purchased on the insurance exchanges.
Memorial Sloan Kettering is an in-network provider with HealthSmart’s Accel, HSPC, and HPO networks.
Memorial Sloan Kettering is a designated Center of Excellence by Humana.
Memorial Sloan Kettering is a designated Center of Excellence by Interlink Health Services.
Memorial Sloan Kettering is a designated Center of Excellence by Lifetrac.
Memorial Sloan Kettering is an in-network provider for all MagnaCare health plans except those products you can buy through the insurance exchanges.
In New York: Memorial Sloan Kettering’s New York locations are in-network with the Emblem
In New Jersey: Memorial Sloan Kettering’s New Jersey locations in Basking Ridge, Bergen and Monmouth are in-network with the Horizon Medicare Advantage Plan. This plan is not accepted for care provided at MSK’s New York locations.
If you are enrolled in any other Medicare Advantage plan, please contact your insurance carrier to determine your benefits and coverage at Memorial Sloan Kettering since your access may be limited.
Memorial Sloan Kettering is an in-network provider with some Multiplan/Beech Street/PHCS plans. Contact your insurance carrier to find out if your plan provides in-network access to Memorial Sloan Kettering.
Memorial Sloan Kettering is a designated Center of Excellence by Multiplan.
If you are covered by more than one insurance plan, you will want to determine your benefits from both plans. First, you need to determine which one is your primary insurance provider by contacting your employee benefits office or your insurance carriers. After you find out which is your primary insurance provider, you should then contact your insurance carrier to determine if you have access to Memorial Sloan Kettering.
Memorial Sloan Kettering is an in-network provider with some MVP plans. Contact your insurance carrier to find out if your plan provides in-network access to Memorial Sloan Kettering.
Memorial Sloan Kettering is an in-network provider for New York State employees who have enrolled in UnitedHealthcare's Cancer Resource Services. If you have the Empire Plan, you should call Cancer Resources Services at 866-936-6002 to verify and enroll in this coverage.
Memorial Sloan Kettering is in-network with Oscar’s Circle Plus Network, a part of its Small Group Broad line that is offered only to select small business groups. Oscar does not include Memorial Sloan Kettering as an in-network provider for any of its individual plans. Please confirm eligibility with your insurance carrier.
We have agreements with several insurance companies that may provide additional coverage for cancer patients. These benefit programs include:
- AXA Assistance USA
- Beech Street
- Integrated Health Plans
- National Health Administrators
- National Preferred Provider Network
- UnitedHealthcare's Cancer Resource Services
- United Resource Network
- Veterans Choice Program
Memorial Sloan Kettering is an in-network provider with Oxford’s Freedom and Liberty plans as well as the Metro Plan (which is only offered to small business groups and no longer offered as individual plans). Please confirm with your insurance if you need a one-time referral. Note: Oxford’s Medicare Managed Care plan — Secure Horizon — does not include Memorial Sloan Kettering as an in-network provider. Oxford does not include us in any of the plans you can buy through the insurance exchanges.
Memorial Sloan Kettering is an in-network provider with the World Trade Center Health Program.
Memorial Sloan Kettering is an in-network provider with QualCare's PPO and HMO/POS network.
Memorial Sloan Kettering is a designated Center of Excellence by Specialty Care Management.
Hospital and physician services may be covered by TRICARE. Please call your TRICARE plan to confirm coverage at Memorial Sloan Kettering.
Memorial Sloan Kettering is an in-network provider with UnitedHealthCare's HMO, POS, and PPO plans. Please confirm with your insurance if a one-time referral is needed.
UnitedHealthCare's Medicare Managed Care plan does not include Memorial Sloan Kettering as an in-network provider.
United does not include us in any of the plans you can buy through the insurance exchanges.
Memorial Sloan Kettering is a designated Center of Excellence by UnitedHealthcare.
Contact and Location
Memorial Sloan Kettering has locations throughout New York City, Long Island, New Jersey, and Westchester. These locations offers many services, including screening, chemotherapy, and medical testing.
MD, University of Chicago
General Surgery - Brigham and Women's Hospital
Surgical Oncology - Memorial Sloan Kettering Cancer Center; Colon and Rectal Surgery - Mount Sinai Medical Center
Surgery; Colon and Rectal Surgery
As a surgical oncologist, I specialize in treating cancers of the gastrointestinal tract such as colon cancer, rectal cancer, anal cancer, small bowel cancers, and appendiceal cancer. I am skilled at treating primary, metastatic, and recurrent tumors. My expertise in minimally invasive (laparoscopic and robotic) surgery enables me to remove tumors without causing significant trauma to the patient. Whenever possible, I use nerve-sparing surgical techniques that preserve sphincter, bladder, and sexual function.
My clinical research focuses on increasing the accuracy of tumor staging and improving the methods of predicting outcomes following cancer surgery. I monitor and update Memorial Sloan Kettering’s colorectal cancer database, which we use to track patient outcomes and ensure that we are providing the highest quality of care. My laboratory research focuses on understanding the mechanisms underlying tumor spread and metastasis and on targeting those mechanisms in designing effective treatments. This work includes developing new tools to identify and measure tumor DNA in the bloodstream. I am also the surgical lead for the international prospective randomized trial PROSPECT, which is aimed at individualizing rectal cancer treatment in order to improve outcomes and reduce treatment-related toxicity.
In my practice, I emphasize personalized patient care. Physician assistants, nurses, and staff at our clinic pay careful attention to each patient’s particular needs. We also emphasize a team approach and work closely with specialists in radiation oncology, medical oncology, and other services. Members of this multidisciplinary team discuss individual cases at our weekly conferences with the goal of providing the most comprehensive care possible.
I have served as MSK’s Medical Staff President, Chair of the Colorectal Task Group for the Society of Surgical Oncology, Colorectal Track Leader for the Education Committee of the American Society of Clinical Oncology, and Program Chair of the Annual Meeting of the American Society of Colon and Rectal Surgeons. Currently, I serve on the staging committee and the precision medicine committee of the American Joint Committee on Cancer, which works on updating the colorectal cancer staging system used by cancer centers throughout the United States.
I am a member of the editorial boards of the Journal of Clinical Oncology, Annals of Surgical Oncology, International Journal of Surgery, and Scientific American Surgery, and I serve as the Colorectal Surgery section editor for UpToDate, an online resource for patients and physicians. I often review submitted manuscripts for the New England Journal of Medicine, Science, the Journal of the American Medical Association, and Lancet Oncology. My publications include over 250 research articles, book chapters, reviews, and editorials on a variety of topics, such as laparoscopic and robotic surgery, the biology of colon and rectal cancers, the treatment of rare anorectal tumors, cancer staging, predictors of outcomes following surgery, and the mechanisms of tumor metastasis. I also lecture nationally and internationally on the management of colorectal, anal, and appendiceal cancers and on the latest advances in minimally invasive surgery.
In my practice, I emphasize personalized patient care. Physician assistants, nurses, and staff at our clinic pay careful attention to each patient’s particular needs.
Awards and Honors
- Castle Connolly: New York Magazine Top Doctors (2012-2020)
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.
Research and Publications
Selected Book Chapters
“Adenocarcinoma of the colon and rectum.” Weiser MR, Saltz LB, Posner MC. In: Shackelford’s Surgery of the Alimentary Tract. 7th ed. Yeo CJ, ed. Philadelphia: WB Saunders; 2012.
“Left hemicolectomy for cancer.” Weiser MR. In: Mastery of Surgery. 6th ed. Fischer JE, ed. Chicago: Lippincott Williams & Wilkins; 2012.
“Endorectal ultrasound for preoperative staging.” Loh B, Weiser MR, Wong WD. In: Intersphincteric Resection of Low Rectal Tumors. Schiessel R, Metzger P, eds. New York: Springer; 2012.
“Rectal cancer.” Kim H, Weiser MR. In: Clinical Scenarios in Surgery: Decision Making and Operative Techniques. Dimick JB, Upchurch GR Jr, Sonnenday CJ. Philadelphia: Lippincott Williams & Wilkins; 2013.
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.
Doctors and faculty members 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.
MSK requires doctors and faculty members 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.
Martin R. Weiser discloses the following relationships and financial interests:
No disclosures meeting criteria for time period
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 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, 2019 through disclosure submission in spring 2020). This data reflects interests that may or may not still exist. This data is updated annually.