The nationally recognized faculty in the UC Davis Department of Radiation Oncology focus their research on innovative treatment approaches to manage many cancers types.

Our broad interests include clinical trials and translational research on a variety of subjects. Some of our focus is on low-dose radiation biology, 3-D conformal radiation therapy, intensity-modulated radiotherapy, stereotactic radiotherapy and radiosurgery, high-dose radiotherapy, chemoprevention, quality of life, image-guided radiotherapy and translational research. Numerous departmental databases have been established that emphasize clinical outcomes and image-guided radiotherapy for performing high-quality, retrospective research. Our research has been published in many high-profile journals, and is frequently cited by radiation oncologists outside our facility.

Research faculty

Richard Valicenti, M.D.
Professor
Department Chair of Radiation Oncology

Dr. Richard Valicenti’s research focus includes the development of new treatment strategies for prostate cancers. He has published extensively on the use of IMRT and IGRT as it improves techniques in radiation therapy delivery. He also has interest in studying the quality of life after radiation treatment for prostate cancer, focusing on both the preservation of sexual function and optimally managing sexual dysfunction after radiation therapy. Dr. Valicenti is a nationally-recognized researcher in the area of post-prostatectomy radiation therapy and has led several national and investigator-initiated clinical trials. These trials are available through the Radiation Therapy Oncology Group, for which Dr. Valicenti is the Principal Investigator at UC Davis.

Allen M. Chen, M.D.
Assistant Professor
Director, Residency and Fellowship Training Program

Dr. Chen is a physician scientist with a research focus on head and neck cancers. He and his research team have published extensively on the benefits of IMRT and IGRT to improve the accuracy and precision of high-dose radiation therapy. He has a specific interest in brachial plexus nerve injuries after radiation and developed current recommendations used by the Radiation Therapy Oncology Group. Dr. Chen has also done extensive laboratory research on the potential of stem cell engineering to protect the salivary glands from radiation-induced dysfunction and to better understand mechanisms underlying the exquisite radiosensitivity of HPV-related head and neck cancers among non-smokers. Dr. Chen is also investigating techniques which may allow in vivo dosimetry using molecular transcripts obtained from oral cavity samples before and during radiation therapy for head and neck cancers.

Ruben Fragoso, M.D., Ph.D.
Assistant Professor

Dr. Fragoso’s research is focused on the immune system. He has studied the signals required for T cell lineage commitment, specifically the CD4 and CD8 co-receptor signals required to drive thymocytes to their respective lineages. His research has also included tumor surveillance by the immune system as well as glioblastoma multiforem, an aggressive grade IV glioma. A specific research interest for Dr. Fragoso includes cancer “stem” cells, a small subpopulation of a cancer tumor that can repopulate the tumor and recapitulate the histology. His research has shown these cancer stem cells are more resistant to chemotherapy and radiation, and are believed to be the culprits for recurrence. He is currently exploring adoptive immunotherapy in an attempt to use the immune system’s cells to better target these cancer stem cells.

Jyoti Mayadev, M.D.
Assistant Professor

Dr. Mayadev’s research focus is primarily on gynecological and breast malignancies, with an emphasis on brachytherapy and three-dimensional treatment planning aspects. Her research investigates image-guided brachytherapy for locally advanced cervical cancer, focusing on efforts to improve the therapeutic ratio in order to maximize tumor control and minimize normal tissue toxicity. Her research also includes in-depth studies of cervical motion both during external beam radiation treatment and in between treatments. Furthermore, Dr. Mayadev is investigating optimal dose delivery for breast cancer patients who are treated after a mastectomy, and those being treated with accelerated partial breast irradiation.

Arta Monjazeb, M.D., Ph.D.
Assistant Professor

Dr. Monjazeb is a clinician scientist and focuses his basic science research on tumor immunology and harnessing the immune system to fight cancer, on which he collaborates with Dr. William Murphy. Under the right circumstances radiotherapy not only induces tumor cell kill but may also alter the immunosuppressive tumor microenvironment. Thus, Dr. Monjazeb explores how radiotherapy can be used with immune modulation to promote anti-tumor immune responses. Clinically, Dr. Monjazeb is interested in translating his basic science research into the clinic. He is studying – within the setting of clinical trials – the use of advanced imaging and radiotherapy techniques to improve the outcomes of patients with sarcomas and gastrointestinal malignancies. He has recently published a study examining how FDG-PET response to chemo-radiotherapy can be used to determine which esophageal cancer patients may benefit from surgery.