Memorial Sloan Kettering radiation oncologist Diana Roth O'Brien

Diana Roth O’Brien, MD, MPH

Radiation Oncologist

Clinical Expertise

Image-Guided Radiotherapy (IGRT); Intensity Modulated Radiotherapy (IMRT); Stereotactic Body Radiotherapy (SBRT); Stereotactic Radiosurgery (SRS); Central Nervous System Tumors; Breast Cancer; Prostate Cancer; Lung Cancer; Head & Neck Cancer; Gastrointestinal Cancers; Gynecologic Cancers


Contact and Location

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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.

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About Me


MD, MPH, SUNY Downstate College of Medicine


Radiation Oncology – NewYork-Presbyterian/Weill Cornell Medical Center

I am a radiation oncologist who specializes in using cutting-edge radiotherapy techniques to treat a variety of cancers. These techniques include image-guided radiation therapy, intensity modulated radiation therapy, stereotactic radiosurgery, and stereotactic body radiotherapy. From early in my medical training, I was drawn to radiation oncology because of the deeply multidisciplinary nature of cancer care. MSK combines a collaborative environment, effective and innovative technology, and extensive resources that allow me to ensure that all of my patients receive optimal care.

Much of my research has focused upon identifying causes of, and reducing side effects associated with, radiotherapy. I am passionate about using my expertise and technology to ensure that my patients not only have their cancer effectively managed, but enjoy the best possible quality of life for years and decades following their treatment. During medical school, in addition to my medical degree, I pursued a Master of Public Health. This additional training has made me acutely aware of how many broad societal factors — beyond the scope of clinic visits — deeply influence the decisions that patients make. As a result, my research has also investigated the barriers that patients face in completing optimal, timely care, and methods to mitigate these obstacles.

For many patients, radiotherapy is a largely unknown and daunting process; as such, I prioritize listening and educating. Regardless of diagnosis, each patient brings unique perspective, values, concerns, and needs to a medical encounter. My aim is to explain complex treatment plans patiently and in an approachable way, such that my patients feel empowered to make informed, personalized decisions, and prepared to embark upon radiotherapy.

Outside of the office, I enjoy traveling, SCUBA diving, knitting, and spending time with my dogs.

My aim is to explain complex treatment plans patiently and in an approachable way, such that my patients feel empowered to make informed, personalized decisions, and prepared to embark upon radiotherapy.

-Dr. Roth O’Brien

Awards and Honors

  • Delta Omega Alpha Public Health Honor Society (2015)
  • Alpha Omega Alpha Honor Medical Society (2015)
  • Best of ASTRO Abstract (2017)
  • The Radiosurgery Society Resident Committee (2019)


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

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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. Roth O’Brien’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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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.

Diana Roth O’Brien 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, 2020 through disclosure submission in spring 2021). 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

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