Our Physicians


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Dr. Chad Sila graduated Summa Cum Laude from UC Riverside with a degree in Biological Sciences. He earned his medical degree from Loma Linda University where he graduated in the top 1% of his class. He completed his residency in Radiation Oncology at Loma Linda University, where he also served as Chief Resident, and scored in the top 1% nationally on the American College of Radiology in-service examinations. During his training, he presented research on Glioblastomas and Arteriovenous Malformations at the American Society for Radiation Oncology (ASTRO) Annual Conference. Dr. Sila also completed additional subspecialty training in MRI-based HDR Brachytherapy and Stereotactic Radiosurgery/Stereotactic Body Radiation Therapy at UC San Diego Moores Cancer Center.

Dr. Sila places a special emphasis on the mental and spiritual care of his patients. He is a firm advocate of the concept of "whole person care," believing that medicine is best practiced by compassionate, caring physicians who combine strong clinical acumen and cutting edge technology with an understanding of the unique needs of cancer patients.


Dr. Sila is a a member of the American Society for Radiation Oncology (ASTRO), the American Brachytherapy Society (ABS), the Radiological Society of North America (RSNA), and the American Society of Clinical Oncology (ASCO).



Dr. Arthur Chung completed his internship and specialty residency training in Radiation Oncology at Loma Linda University, where he also served as Chief Resident. During his specialty residency training, he was heavily involved in academic research, authoring peer-reviewed articles in the International Journal of Radiation Oncology Biology Physics and presenting research at the annual meetings of the American Society for Radiation Oncology (ASTRO).


Dr. Chung has also served on the ASTRO Global Health Committee, working with other physicians to improve global cancer care. He has received several awards including the RSNA Roentgen National Research Award and a 1st-place award for a research presentation at the Annual Medical Conference at Loma Linda University for his work on cavernous sinus meningiomas and optic nerve sheath meningiomas. 

Dr. Chung embodies the philosophy of whole-person care, combining compassionate, personal care with the state-of-the-art techniques for each patient.

Dr. Chung is a member of the American Society for Radiation Oncology (ASTRO), the American Brachytherapy Society (ABS), the Radiological Society of North America (RSNA), and the American Society of Clinical Oncology (ASCO).



Dr. David Hsu is a Board Certified Radiation Oncologist. He was born and raised in Taiwan and immigrated to US when he was 14. After graduating from San Marino High School, he received his BA degree in Biology from UC Berkeley. He received his MD and MBA degrees from Creighton University in Omaha, NE. He completed his residency in Radiation Oncology at Loyola University Medical Center in Chicago. Dr. Hsu also received MPH (Master of Public Health) degree from the University of Illinois at Chicago.

After completing his residency, Dr. Hsu practiced at Eisenhower Medical Center in Rancho Mirage, CA. He then moved to Omaha, Nebraska to help build and establish a new cancer center for that region, and served as the Chief of Radiation Oncology.


Dr. Hsu is now the Medical Director of the International Cancer Center as part of the Advanced Oncology network. He is fluent in English and Mandarin Chinese.



Dr. Randall Scharlach is the radiation oncologist at Golden State Cancer Center in San Fernando Valley. His primary focus is providing patients with an environment that is conducive to optimal patient recovery.

Dr. Scharlach is a 1995 graduate of the UCLA School of Medicine. He completed his residency in Radiation Oncology at Yale University in 2000, where he served as Chief Resident. Dr. Scharlach is recognized as an expert in the most advanced radiotherapeutic technologies, including IMRT and IGRT, as well as stereotactic radiation. He is also trained and experienced in the use of High Dose Rate (HDR) brachytherapy as well as Stereotactic Body Radiotherapy (SBRT).


Dr. Scharlach's publications include research in endometrial cancer and authorship of a textbook chapter on salivary gland malignancies. He has presented well over fifty lectures for professional education on multiple topics including the use of radioprotective drugs, the effects of hypoxia with radiation, oncology pain management, the use of cannabinoids in oncology, and the development of advanced radiotherapy technologies. 


Dr. Lesley Lawrenson received both BS and MS degrees from UC San Diego, then earned a PhD in Cancer Genomics and an MD degree from Wayne State University School of Medicine. She completed Radiation Oncology specialty residency training at UC Irvine School of Medicine, serving as Chief Resident.


Dr. Lawrenson has demonstrated a passion for clinical research, with publications in the fields of Image-Guided Radiation Therapy (IGRT), High-Dose-Rate radiation therapy (HDR), and Stereotactic Body Radiation Therapy (SBRT/SABR).

As part of the Advanced Oncology team, Dr. Lawrenson is dedicated to providing compassionate and personal cancer care for all of her patients.






As our Chief Network Officer, Anthony Tsun spearheads Advanced Oncology's efforts to build impactful partnerships with well-respected health systems, medical groups, and various physician groups across the nation. Aiming to make seamless connections between patients, cancer specialists and health networks, Anthony has been a driving force in developing and building partnerships with the Advanced Oncology network as he leads our business development, marketing, and community relations teams. 


Anthony Tsun has a management degree in Hotel Operations and Marketing, and his career has successfully diversified over the last 20 years to Healthcare Management as he developed several regional medical imaging and radiation oncology centers in Southern California. He also serves as Chief Operating Officer of Advanced Oncology Center in West Covina.