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Rachel Jimenez, MD

Massachusetts General Hospital
Boston, Massachusetts

Titles and Affiliations

Assistant Professor of Radiation Oncology, Harvard Medical School
Chair for Quality and Safety, Department of Radiation Oncology, Massachusetts General Hospital

Conquer Cancer, The ASCO Foundation

Research area

Designing safer breast cancer radiation treatments to reduce cardiac toxicity.


Approximately 60 percent of breast cancer patients receive radiation therapy as part of their care. In the case of breast cancers that occur in the left breast, unintended radiation exposure to the heart can increase the risk of heart failure. Heart failure related to radiation is thought to be caused by stiffening (fibrosis) of the heart tissue, which eventually leads to irreversible dysfunction of the heart muscle. Early studies suggest that proton beam radiation, a special form of radiation that allows for precise radiation delivery, may be protective of the heart. It is unknown, however, if proton beam radiation is safe when used according to current standards of hyper-fractionated delivery (higher radiation doses over a shorter time period). As part of her Conquer Cancer Foundation Advanced Clinical Research Award, Dr. Jimenez and her team will evaluate if proton beam radiation is a safer alternative to conventional radiation.

Progress Thus Far

The team will test whether an accelerated five-day proton therapy radiation regimen, as compared to accelerated conventional radiation, preserves heart function. Sixty patients with left side breast cancer will receive a cardiac MRI before radiation, and six months after radiation, to assess for heart stiffening. The researchers will also test for other indicators of heart function and injury. The study is IRB approved and is currently accruing patients.

What’s next

Successful completion of this study will lay a foundation for a larger multi-center trial, focused on patients at highest risk of radiation-induced cardiac injury.


Rachel Jimenez, MD is an Assistant Professor of Radiation Oncology at Harvard Medical School and the Chair for Quality and Safety in the Department of Radiation Oncology at Massachusetts General Hospital. She holds an AB from Harvard University, an MD from Harvard Medical School, and completed her residency and chief residency training in the Harvard Radiation Oncology Program.

Dr. Jimenez’s clinical practice focuses on the treatment of patients with breast cancer. She has special expertise in the use of proton therapy and the reduction of cardiac toxicity and other late toxicities associated with breast radiation. To that end, she runs several clinical trials exploring the prevention of cardiac toxicity after breast radiotherapy. Her research has informed consensus guidelines and she has made novel contributions, specifically in the role of proton beam therapy for patients with breast cancer.

She is a prior recipient of grant funding through the American Cancer Society and The Greenwall Foundation. Dr. Jimenez serves on multiple national committees in Oncology including within the cooperative groups (NRG Oncology – Breast Locoregional Subcommittee, Alliance for Oncology in Clinical Trials – Ethics Committee), and professional societies (ASTRO, ASCO, ABR). She also serves on patient advocacy organizations including (SBC).

BCRF Investigator Since