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Richard C. Zellars, MD

Professor and Chairman
Department of Radiation Oncology
Indiana University School of Medicine
Indianapolis, Indiana

Current Research

  • Seeking to improve outcomes in breast cancer with novel approaches to enhance radiation therapy.

  • Two clinical trials are accruing patients to test both pre-operative and adjuvant (preventive) treatment for breast cancer.

  • Radiation therapy is an important component of breast cancer treatment, but not all women respond equally. These trials may change standard of care for radiation therapy and improve outcomes in breast cancer.

For many women, neoadjuvant chemotherapy (NAC) can result in complete response, meaning the tumor is no longer clinically detectable after therapy. Women with residual disease after NAC, however, have worse outcomes than those women who achieve a pathologic complete response.

Pre-operative radiation has been used with NAC, and is well tolerated, but this combination has not clearly shown a significant improvement in the complete response rates compared to NAC alone. PARP inhibitors may be an effective strategy to improve response to pre-operative radiation by preventing repair of radiation-induced DNA damage.

Dr. Zellars is conducting a clinical trial to test this combination (NCT01618357). The trial is  open to accrual at affiliated hospitals within the Johns Hopkins Clinical Research Network and will open soon at the Simon Cancer Center at Indiana University.  As of 2017, three women have been treated with this regimen, and all showed benefit with the PARP inhibitor.

Over the last 30 years, breast conserving surgery plus radiation has become the standard recommendation for early stage breast cancer. Researchers are now considering whether decreasing radiation exposure with new techniques such as partial breast irradiation (PBI) may have similar benefits.

With support from BCRF, Dr. Zellars’s team was the first to show that PBI may be a safe and expeditious treatment option for many women with breast cancer.  Unfortunately, in some women, PBI alone may not suffice. Dr. Zellars is conducting a clinical trial (NCT01928589) to compare two combination approaches to see which achieves the best results in this high-risk population.

The trial will compare response rates with radiation prior to chemotherapy to those who receive radiation concurrent with chemotherapy. Results from this study may provide women with an alternative treatment choice to reduce the risk of recurrence.

The trial is open to accrual at affiliated hospitals within the Johns Hopkins Clinical Research Network and the Simon Cancer Center at Indiana University. The University of Texas Health Science Center at San Antonio will also begin enrolling patients soon.

Previous results showed a 15-30 percent local failure following PBI in triple negative or ER-negative patients. However, to date, no failures in ER- patients have been seen in this trial. 


Richard Zellars is Professor and Chairman of the Department of Radiation Oncology at Indiana University and the Director of the IUH Radiation Oncology Service line.  Before he joined the IU team in early 2015, he was  an Associate Professor in the Dept. of Radiation Oncology at the Johns Hopkins University School of Medicine, and Assistant Director of Clinical trial Accrual at the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins. 

He graduated from the Johns Hopkins School of Medicine and subsequently completed a residency in Radiation Oncology at University of Michigan where he was Chief Resident from 1995-1996.  Dr. Zellars was an Assistant Professor/Vice Chair and Clinic Director of the Dept. of Radiation Oncology at the University of Texas Health Science Center at San Antonio.  Prior to returning to Johns Hopkins in 2000, he was an Assistant Professor in the Dept. of Radiation Medicine at Georgetown University in Washington DC. 

His research aims to improve the facility, safety and efficacy of radiation for breast cancer.  Dr. Zellars is a member of the American Society for Therapeutic Radiology and Oncology (ASTRO), and the American Society of Clinical Oncology (ASCO).  He also serves on the National Comprehensive Cancer Network (NCCN) Breast Cancer Panel and is Co-Chair of the NCI Breast Oncology – Local Disease (BOLD) Task Force.   Dr. Zellars has been listed as one of the top doctors for women in Redbook, Ladies Home Journal and Newsweek magazines.

BCRF Investigator Since


Donor Recognition

The Delta Air Lines Award

Area(s) of Focus