Simon N. Powell, MD, PhD, FRCP

Radiation Oncologist

Chair, Department of Radiation Oncology; Enid A. Haupt Chair in Radiation Oncology

Conditions Treated:

Simon N. Powell, MD, PhD, FRCP -- Chair, Department of Radiation Oncology; Enid A. Haupt Chair in Radiation Oncology

About Me

I am a radiation oncologist who cares for people with breast cancer. I am Chair of the Department of Radiation Oncology and have been practicing medicine for 35 years. I see approximately 200 new breast cancer patients each year at Memorial Sloan Kettering in Manhattan.

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When patients come to see me, they are worried about whether we can get rid of their cancer. Many patients read about their diagnosis on the internet, and the information they find can be very scary. I always make it a priority to answer all of my patients’ questions so that they feel reassured. I want them to know that they are getting the best care possible.

My research is focused on breast cancer. I have received funding from the National Institutes of Health since 1992 and am an expert in understanding how DNA repair genes like BRCA1 and BRCA2 work to fix DNA damage, as well as how a person’s genetics may influence his or her response to radiation therapy.   

 At MSK, we are leading the way in the use of advanced radiation techniques to ensure our patients have the best outcomes possible. For our early-stage breast cancer patients, we are using hypofractionated whole-breast irradiation. This means patients are receiving fewer total treatment sessions in a shorter time period, with a slightly higher dose given each treatment day. We also have a robust delivery system for partial breast irradiation. We now deliver treatment once per day, which helps our patients tolerate their treatment better.

I have experience treating people with recurrent or metastatic triple-negative breast cancer using radiation in combination with chemotherapy, targeted therapies, and immunotherapies.

For some people, breast cancer treatment can negatively affect the heart. At MSK, we have a program dedicated to assessing this problem. We are leaders in the field of deep inspiration breath-hold techniques, which can help lessen the cardiac side effects for our breast cancer patients. We are also using proton therapy to target tumors more precisely, which can reduce the risk of other treatment-related side effects.

I am a member of advisory boards for several cancer centers in the US and abroad, including the Netherlands Cancer Institute, Winship Cancer Institute of Emory University, University of Michigan Cancer Center, and the University of Florida Health Cancer Center.

In my free time, I enjoy theater, opera, ballet, country-specific versions of history, football, American football, and golf.

  • Clinical Expertise: Radiation Oncology; Breast Cancer
  • Awards and Honors: Castle Connolly: New York Magazine Top Doctors; America’s Top Doctors; Top Doctors New York Metro Area; Boston Top Doctors; St. Louis Top Doctors
  • Languages Spoken: English
  • Education: MD, PhD, University of London (UK)
  • Residencies: Hammersmith Hospital; Whittington Hospital (UK)
  • Fellowships: Royal Marsden Hospital (UK); Harvard Medical School
  • Board Certifications: Radiation Oncology; Internal Medicine (UK)

My Research

View my lab

See Simon N. Powell’s laboratory
research at Memorial Sloan Kettering.


Visit PubMed for a full listing of Simon N. Powell’s journal articles

Pubmed is an online index of biomedical articles maintained by the U.S. National Library of Medicine and the National Institutes of Health.

Clinical Trials

Research is integral to our mission at Memorial Sloan Kettering, and clinical trials help us discover better forms of patient care and treatment. For you, this could mean access to a new therapy or therapy combination. Click to see a list of the trials I’m currently leading.


Most major health insurers offer plans that include MSK as one of their in-network providers. If MSK is in-network, it means all our doctors are too. Medicaid and New York State Medicare also provide benefits for care at MSK.

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