Robert Ash, M.D., radiation oncologist

Robert B. Ash, M.D.

  • Assistant Clinical Professor, Department of Radiation Oncology
  • Medical Director of Radiation Oncology, St. Joseph of Orange
  • Radiation Oncologist

Robert B. Ash, M.D.

Clinical Specialties
  • Radiation Oncology
Areas of Expertise
  • Thoracic Cancer
  • Genitourinary Tumors
  • Prostate Brachytherapy
  • Stereotactic Radiosurgery
Robert Ash, M.D., brings more than two decades of radiation oncology experience to City of Hope. Throughout his career he has been top-rated for excellence in skill and interaction with his patients.

Highly trained in all aspects of radiation therapy, Dr. Ash specializes in complex procedures involving radioactive implants, precision stereotactic radiosurgery for brain tumors, as well as brachytherapy for prostate cancer.

A native of Canada, Dr. Ash received his medical degree from Memorial University of Newfoundland and continued his training at University of Western Ontario and University of California San Francisco.

A strong believer in collaboration, Dr. Ash sees the role of the radiation oncologist as a key member of a total team dedicated to providing patients with the best possible care.
  • 2018 - present, Assistant Clinical Professor, Department of Radiation Oncology, City of Hope, CA
  • 2007 - present, Medical Director of Radiation Oncology and Radiation Oncologist, St. Joseph Hospital of Orange, Orange, CA
  • 2000 - 2007, Associate Professor, University of Western Ontario, London, Ontario
  • 2000 - 2007, Staff Radiation Oncologist, London Regional Cancer Centre, London, Ontario
  • 2001 - 2005, Director, Undergraduate Medical Education for Oncology, University of Western Ontario, London, Ontario
Affiliate Location
St. Joseph Hospital of Orange
The Center for Cancer Prevention & Treatment
1000 W. La Veta Ave.
Orange, CA 92868


  • 1995, M.D., Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada
  • 1991, B.S., Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada
  • 1990, B.M., Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada


  • 2000, Postgraduate Training IMRT, University of California San Francisco, San Francisco, CA


  • 2000, Radiation Oncology Residency, University of Western Ontario, London, Ontario, Canada
Moshe E. Stein, Zvi Bernstein, Ufuc Abacioglu, Meric Sengoz, Robert C. Miller, Amichai Meirovitz, Abadou Zouhair, Salvador Villa Freixa, Philip H. Poortmans, Robert Ash, Abraham Kuten. Small Cell (Neuroendocrine) Carcinoma of the Prostate: Etiology, Diagnosis, Prognosis, and Therapeutic Implications – A Retrospective Study of 30 Patients from the Rare Cancer Network, The American Journal of The Medical Sciences, December 2008, Vol. 336, No. 6.

Yu E, Tai P, Younus J, Malthaner R, Truong P, Stitt L, Rodrigues G, Ash R, Dar R, Yaremko B, Tomiak A, Dingle B, Sanatani M, Vincent M, Kocha W, Fortin D, Inculet R. Postoperative extended-volume external-beam radiation therapy in high-risk esophageal cancer patients: a prospective experience. Curr Oncol. 2009 Aug;16(4):48-54.

William Y. Song, Bernard Chiu, Glenn S. Bauman, Michael Lock, George Rodrigues, Robert Ash, et al. Prostate contouring uncertainty in mega-voltage computed tomography (MVCT) images acquired with a helical tomotherapy unit during image-guided radiation therapy (IGRT). IJRPO, 2006; Jun 1;65(2):595-607.

Kavitha Passaperuma, Robert Ash, Varagur Venkatesan, et al. Pelvic chemoradiotherapy after chemotherapy for metastatic bladder cancer. The Canadian Journal of Urology; April 2006; 13(2);3009-3015.

Robert B. Ash, Gregory M.M. Videtic. Letter to the Editor:  Radiation Recall Dermatitis after the use of the Anorexiant Phentermine in a Patient with Breast Cancer. The Breast Journal, 2006; Vol. 12, No. 2, pp186-187.

Gregory Videtic, Pauline Truong, Robert Ash, et al. Does Sex Influence the Impact that Smoking, Treatment Interruption and Impaired Pulmonary Function have on Outcomes in Limited Stage Small Cell Lung Cancer Treatment? Can Respir J, 2005; Vol. 12, No 5, pp 245-250.

Videtic GM, Stitt LW, Ash RB, et al. Impaired diffusion capacity predicts for decreased treatment tolerance and survival in limited-stage small cell lung cancer patients treated with concurrent chemoradiation. 2004 Lung Cancer; 2004; 43: 159-166.

Rodrigues G , Chan A , Ash RB, et al. Prognosis of superior vena cava obstruction in lung cancer. Lung Cancer 2003; vol. 41: (supplement 2), p.S259.

Yu E, Dar, AR, Ash RB, et al. Is extended volume of external beam irradiation beneficial in post esophagectomy high risk patients receiving combined chemoradiation therapy?  Int J Radiat Oncol Biol Phys 2001; 50(5):#13 - p1384.
  • College of Physicians and Surgeons of Ontario
  • Canadian Association of Radiation Oncologists
  • Canadian Medical Association
  • American Society of Therapeutic Radiology and Oncology
  • American College of Radiology
  • Royal College of Physicians and Surgeons and Canada
  • Ontario Medical Association
  • International Association for the Study of Lung Cancer
  • 2006, Provincial Association of Interns and Residents of Ontario "Excellence in Clinical Teaching" award
  • 2003, "Best Curriculum on Earth" award for teaching excellence from Meds III, University of Western Ontario Trinity-Conception Regional Health Foundation
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