Naren Ramakrishna, MD, PhD, is the Director of Proton Therapy, and Neurologic and Pediatric Radiation Oncology, and Co-Director of the Brain and Spine Tumor Program at Orlando Health UF Health Cancer Center. Dr. Ramakrishna completed his bachelor's degree in biology at Johns Hopkins University, and graduate education in the Medical Scientist Training Program at Cornell University Medical College where he received his MD, and a PhD in Cell Biology and Genetics.
Dr. Ramakrishna served for eight years on the faculty of Harvard Medical School where he was an Instructor in Radiation Oncology and was the Chief of Central Nervous System Radiation Oncology at Dana-Farber Cancer Institute and Brigham and Women's Hospital, and the Director of the Central Nervous System Radiosurgery/Radiotherapy Fellowship program. He is currently a Professor in Radiation Oncology at the University of Central Florida College of Medicine. His current research centers on radiobiological modeling, and advanced applications of stereotactic radiosurgery, and proton treatment for primary and metastatic brain tumors.
Orlando Medical News asked Dr. Ramakrishna about the Center and some of the controversies surrounding proton therapy in general.
OMN: Can you update us on the innovative factors involved in your program at the center and why that is drawing patients from around the world for treatment at the center?
Dr. Ramakrishna: Our multidisciplinary cancer program pursues innovative clinical research and treatment including cancer vaccines, immunotherapy, cellular therapy, tumor-treating fields, and development of treatment guidelines which are referred to internationally. Our radiation oncology program is recognized for important contributions to the field of image-guided radiotherapy. The proton therapy program was among the first single vault centers internationally and is known for its multidisciplinary expertise, diverse patient mix, and advanced image-guidance capabilities.
OMN: Tell us about the versatility of the program in treating many different kinds of cancer with the unit?
Dr. Ramakrishna: The range of patients treated at our center include those with pediatric cancer, brain and spine tumors, head and neck cancer, breast cancer, lung cancer, lymphoma, sarcomas, and gastrointestinal cancer. This diverse patient mix reflects our disease-specific expertise in these areas and the versatility of our image-guided proton therapy platform. Our proton therapy platform and treatment planning systems have undergone rigorous certification for adult and pediatric clinical trial participation.
OMN: Please explain how the use of advanced mobile CT works with the unit to monitor response of the treatments?
Dr. Ramakrishna: One of the critical factors underlying precise proton therapy is the mapping of patient anatomy, tumor position, and tumor size which may change from day to day. These changes have a greater impact on the quality of proton treatment than on conventional X-ray treatment. The in-room mobile AIRO CT unit allows for monitoring these variables on a daily basis and this facilitates accurate treatment of tumor and better sparing of surrounding normal tissue.
OMN: Critics of proton therapy say the cost isn't justified when looking at the benefits considering purchase and installation of a unit with the relatively small number of patients that qualify for treatment. Can you tell us y0ur views?
Dr. Ramakrishna: Complications following radiation treatment may not manifest for many years following treatment. As the long-term prognosis of cancer patients improve, the number of patients who may benefit from proton therapy increases, as the dose to normal tissue and resulting risk of complications is lower with protons than with conventional X-rays. The economic benefit of this reduction in long term complications is an area of active investigation. At our center, we are modeling this incremental cost/effectiveness ratio for adult brain tumors treated with protons vs. conventional treatment. By doing so, we hope to demonstrate the economic cost-effectiveness of proton treatment for selected patients and improve access for those patients.
OMN: Another criticism is that there haven't been comprehensive studies that compare proton therapy with traditional treatments. Can you also give your views on that and explain why those types of studies may or may not be relevant?
Dr. Ramakrishna: The improvement in dose distribution achievable with proton therapy relative to conventional radiation is indisputable. This prompted the historical use of this modality for critical applications such as pediatric cancers, brain and spine tumors, and certain eye tumors. Given the dosimetric and theoretical advantage in these patient groups, there will likely never be comparative clinical trials comparing outcomes for these high-risk settings. The use of proton therapy for more common cancers has been relatively recent and the long-term data necessary to validate the benefits of treatment will require completion of ongoing clinical trials involving disease sites such as prostate, breast, and lung cancer.
OMN: There has been concern expressed over neutron radiation risk to patients and staff from proton therapy. Can you tell us what the latest information is on that?
Dr. Ramakrishna: Secondary neutrons may be produced both inside and outside the patient during treatment with proton systems as well as high energy conventional X-ray units. However, the magnitude of this neutron exposure is extremely small compared to the delivered dose of protons, and there have been no observed clinical effects attributed to this neutron dose. The occupational exposure for staff to secondary neutrons is mitigated by shielding and distance to safe levels. The level of secondary neutrons is further reduced using pencil-beam scanning systems.
OMN: Can you tell us a little more on what improvements to the unit and the program at the center are planned for the future?
Dr. Ramakrishna: As our clinical volume and range of disease sites expands, we plan to add additional treatment capacity and incorporate next generation dose-shaping and treatment verification technology. We are currently evaluating next generation pencil-beam scanning systems and in vivo dose imaging technology to further enhance our ability to deliver dose accurately and with the least side effects.