Loading Complete
Leif William Ellisen

Leif William Ellisen, MD, PhD

Medical Oncology

Highlights

Age Groups Seen

  • Adults
  • Geriatrics

Languages

  • French
  • English

Gender

Male

About Leif William Ellisen

Dr. Ellisen is Professor of Medicine at Harvard Medical School and Program Director for Breast Medical Oncology at the Mass General Cancer Center. He is also co-Leader of the Breast Cancer Program at the Dana-Farber/Harvard Cancer Center. He received his undergraduate degree from Harvard University, MD and PhD degrees from Stanford University, and completed residency training, oncology fellowship training, and postdoctoral research training at Brigham and Women's Hospital, the Dana-Farber Cancer Institute, and Mass General, respectively. Dr. Ellisen is widely published in the fields of cancer biology, treatment and genetics. As Director of Breast and Ovarian Cancer Genetics at Mass General, Dr. Ellisen's clinical practice is focused on cancer risk assessment, cancer prevention and early detection. Research in Dr. Ellisen's laboratory is in the vanguard of revolutionizing cancer treatment through personalized cancer therapies. Dr. Ellisen is best known for his work on triple-negative breast cancer (TNBC), one of the most aggressive forms of the disease.

Locations

  1. Mass General Brigham Cancer Institute Center for Breast Cancer Medical Oncology at Boston
    • 32 Fruit Street, Yawkey Building, 9th Floor, Suite 9a, Boston, MA 02114
    • Get Directions

Expertise

Education

  • Fellowship: Brigham and Women's Hospital, Hematology/Oncology, 1998
  • Fellowship: Massachusetts General Hospital, Hematology Oncology, 1995
  • Residency: Brigham and Women's Hospital, Internal Medicine, 1994
  • Medical Education: Stanford University School of Medicine, Medicine, 1992

Insurance

Search plans
  • Aetna
  • Beech Street
  • Blue Cross Blue Shield
  • Blue Cross Blue Shield - Indemnity
  • Blue Cross Blue Shield Medicare
  • Cigna
  • Commonwealth Care Alliance
  • Coventry
  • Fallon Health
  • Harvard Pilgrim Health Care
  • Humana
  • Maine Community Health Options
  • Mass General Brigham Health Plan
  • MassHealth
  • Medicaid ME
  • Medicaid NH
  • Medicaid RI
  • Medicaid VT
  • Medicare
  • Multiplan
  • Railroad Medicare
  • Senior Whole Health
  • TriCare
  • Tufts Health Plan
  • Tufts Medicare Preferred
  • United Health Care
  • Wellpoint
  • WellSense
  • WellSense NH

Ratings & Reviews

5 out of 5

62 ratings, 31 reviews

The Patient Satisfaction Rating is an average of all responses to the care provider related questions shown below from our survey. Patients that are treated in outpatient or hospital environments may receive different surveys, and the volume of responses will vary by question.

How likely would you be to recommend this provider to your family and friends?
Search reviews
  • Reviewed on 3/30/2026

    Dr. Ellisen is wonderful!

  • Reviewed on 3/29/2026

    An extraordinary physician. Am lucky to be a patient

  • Reviewed on 3/29/2026

    By chance, my sister had also been assigned Dr. Ellisen for her treatment, so I had heard a fair bit about him in advance, but I can't express how far he exceeded my expectations. His manner is so kind, he didn't just answer every question I had, but often expressed how they were a GOOD question, like he appreciated it, that they were in no way a burden on his time. He explained everything in a way that was easy to understand and with references to research studies. I feel totally comfortable with my treatment in his hands going forward.

  • Reviewed on 3/18/2026

    I've been seeing Dr. Ellisen for the past 20 years annually, and he is always kind, respectful, and always offers for any time I need to call or email him, and he does respond. I'm very appreciative of the care he's given to me over the past 20 years.

  • Reviewed on 3/16/2026

    He's great.

  • Reviewed on 3/9/2026

    Dr. Ellisen was very informative, very calm, very complete with all his answers and all the information he provided. He was very thorough and informative.

  • Reviewed on 2/1/2026

    Dr. Ellisen is the best. He listens, is empathetic and compassionate and very warm and caring. His knowledge is extraordinary and he always takes his time and answers all of my questions. Just a wonderful doctor who is always cheerful.

  • Reviewed on 1/26/2026

    Dr Ellisen is an outstanding Doctor and a highly respected member in his field. He knew the answers to every question that I had and also asked for very important information from me. We liked him very much and I look forward to seeing him again.

  • Reviewed on 1/26/2026

    [redacted] I continue to be thankful and grateful to Doctor Ellisen and his team at MGH. [redacted]

  • Reviewed on 1/12/2026

    Excellence in practice. The doctor listened to me, answered every question, and communicated a clear plan for follow up.

  • Reviewed on 1/7/2026

    Dr Ellisen is a great doctor. He is extremely knowledgeable; personable, thorough, and has a great sense of humor. He reviews all of my treatment options and answers all of my questions. He puts me at ease. He is a great asset to MGH !

  • Reviewed on 1/5/2026

    I've been a patient of Dr. Leif Ellisen for a number of years and he's the best. Thank you.

  • Reviewed on 12/20/2025

    Dr. Ellisen is the best. He had already reviewed my record before coming into the exam room. He explained the type of cancer I had and the progress being made with research. He never rushes through my visit and I always feel I'm getting the best care available.

  • Reviewed on 11/24/2025

    Dr. Ellisen is kind, caring and so knowledgeable. I always feel at ease and empowered when I leave these appointments!

  • Reviewed on 11/23/2025

    Dr. Ellisen explains everything in detail in layman's terminology not medical terminology which is very much appreciated. I do not feel like I'm a number with Dr. Ellisen. He 100% cares about my well being.

  • Reviewed on 11/17/2025

    Dr. Ellisen was very professional but also able to explain my diagnosis in a way that was easy to understand.

  • Reviewed on 11/15/2025

    Incredibly knowledgeable, kind, respectful physician

  • Reviewed on 11/8/2025

    Excellent. Was familiar with and recalled my history or had prepared well for the visit

  • Reviewed on 10/19/2025

    Dr Ellisen is great!

  • Reviewed on 10/14/2025

    Dr. Ellisen was awesome!

  • Reviewed on 9/28/2025

    Listens and provides excellent advise

  • Reviewed on 9/15/2025

    Dr. Leif Ellisen knows very well my medical history, he can well understand patient's felling and give the professional advice. I love this doctor very much

  • Reviewed on 9/15/2025

    Really knowledgeable and personable

  • Reviewed on 9/9/2025

    I've been going for follow ups with Dr. Ellisen for many years and he is always thorough, informative, and caring. One of the best doctors I've seen.

  • Reviewed on 6/29/2025

    Always enjoy my appointment with Dr. Ellisen.

  • Reviewed on 6/29/2025

    Very professional, very knowledgeable, very compassionate and very informative.

  • Reviewed on 6/29/2025

    superior healthcare provider. MGH cancer center is the best

  • Reviewed on 6/24/2025

    HE IS AWESOME

  • Reviewed on 6/18/2025

    Dr. Ellisen is supportive, curious, and remembers details about his patients. He is also knowledgeable, and I appreciate being able to see him.

  • Reviewed on 6/15/2025

    I have been Dr Ellisen once a year for several years and find him to be very knowledgeable, courteous and pleasant. I highly recommend him

  • Reviewed on 5/11/2025

    He is the best