Richard M. Gewanter, MD

Radiation Oncologist

4.8 | 199 reviews

Areas of Expertise

Conditions I Treat

Prostate cancer and conditions
Breast cancers and conditions
Lung cancer

My Specialties

Intensity-modulated radiation therapy (IMRT)
High-dose-rate (HDR) brachytherapy

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English

Get to Know Me

I am a radiation oncologist who sees patients at Memorial Sloan Kettering Nassau, on Long Island. I also see patients at Memorial Hospital in Manhattan.

I treat a wide variety of cancer types, including prostate cancer, bladder cancer, lung cancer, and breast cancer. I have been practicing for 14 years.

I was drawn to a career in radiation oncology while I was in medical school. I was impressed by how radiation oncologists combined biology, technology, and imaging to deliver targeted treatment for people with cancer. At the same time, I felt a calling to this field because of the opportunity to counsel and guide people through one of the most difficult periods in their lives.

As the field of radiation oncology has advanced, I have found it truly gratifying to be able to deliver more effective treatments with fewer side effects. These advances — such as stereotactic radiosurgery and stereotactic body radiation —allow us to greatly reduce treatment times. Patients used to spend eight to nine weeks on a typical radiation course, but with the latest technologies, they can now often complete their treatments in three to five days.

People who come for their first radiation appointment are often fearful, as there can be many unknowns: How will treatment affect quality of life? How will it affect loved ones? They also want to feel confident that they are making the right treatment choices but often feel overwhelmed by the information available on the internet, or from well-meaning friends.

I try to help my patients understand all options. If we as a patient-clinician team decide radiation is the best option, I explain how we will achieve their treatment goals. I make it a priority to develop a bond of trust from the beginning so that my patients can feel confident and reassured.

In addition to my clinical work, I am a member of the prostate cancer research team in MSK’s Department of Radiation Oncology. I have also served as an expert panel member on the American College of Radiology’s Appropriateness Criteria Committee for Lung Cancer.

What I Do at MSK

A radiation oncologist is a cancer doctor with special training in using radiation therapy (RT) to treat cancer with radiation.

Attending Radiation Oncologist

Conditions I Treat

Prostate cancer and conditions
Breast cancers and conditions
Lung cancer
Bladder cancer
Head and neck cancers

My Specialties

Intensity-modulated radiation therapy (IMRT)
High-dose-rate (HDR) brachytherapy

Education

MD, Albert Einstein College of Medicine

Residencies

Radiation Oncology - New York Presbyterian/Columbia University Medical Center

Board Certifications

Radiation Oncology

Awards and Honors

Castle Connolly: America’s Top Doctor (2025)
Castle Connolly: America’s Top Doctor (2024)
Top Doctors New York Metro Area, Castle Connolly (2023)
Castle Connolly: America's Top Doctors (2023)
Castle Connolly Newsday Top Doctors on Long Island (2010-2016)
UJA-Federation of New York, Long Island South Shore Healthcare Professionals honoree (2016)

Insurance Information

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New Patients

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Current Patients

Request an appointment by logging in to MSK MyChart or calling your Care Team. If you are not enrolled in MSK MyChart, ask your Care Team to send you an invitation. You can also go to MSK MyChart and select “Sign up now.”

Contact and Location

Dr. Gewanter sees patients at one location.

Office Phone

516-559-1526

Location

Uniondale, NY

Memorial Sloan Kettering Nassau

1101 Hempstead Turnpike Uniondale NY 11553

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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.

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Clinical Trials

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.

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Research and Publications

Publications on PubMed

Visit PubMed for a full listing of Dr. Gewanter’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.

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Patient Reviews

Your trust is our main concern

We strive to keep reviews trustworthy, honest and fair. Learn more about our patient experience reviews.

4.8 199 reviews

4.8 Provider's Explanations Easy to Understand
4.8 Trusts Provider with Care
4.9 Provider Listened Carefully
4.8 Likelihood of Recommending Provider

Mar 20, 2025

Very impressed with my doctor, in all respects

Mar 20, 2025

Wish the wait in the exam room could be less. Generally have to wait an hour or more before the doctor is available.

Mar 20, 2025

I am very confident that I am in great hands being under the care of Dr G and his team

Mar 18, 2025

Dr Gewanter was kind, thorough and understanding. Excellent provider.

Mar 13, 2025

I was given a check in time of 9:45...had to leave my home at 8:15am to arrive on time. Due to unseen circumstances I didn't meet with the doctor until after 11:30am. I am experiencing enough stress due to my diagnosis. I also have to rely on help with transportation. Not being seen around my appointment time (10am) is unacceptable. If the tables were turned and I showed up 90 minutes late for my appointment would you be happy with that?

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Disclosures

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.

Richard M. Gewanter discloses the following relationships and financial interests:

Pfizer, Inc.
Equity

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, 2023 through disclosure submission in spring 2024). 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 ecoi@mskcc.org.

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