02 Feb Proton Radiation Therapy: Treats Pediatric Brain Tumor With Fewer Long Term Side Effects
MedicalResearch.com Interview with:
Dr. Torunn Yock, MD
Director, Pediatric Radiation Oncology
Associate Professor, Harvard Medical School
Radiation Oncology Quality Assurance
Massachusetts General Hospital, Proton Center
Medical Research: What is the background for this study?
Dr. Yock: Proton radiotherapy is a highly targeted form of radiation therapy that can spare normal tissues better than standard x-ray/photon based radiotherapy. Because, all side effects from radiotherapy come from radiation dose to normal healthy tissues, it is widely believed that proton radiotherapy has great potential to mitigate the side effects of treatment, both acute and long term side effects. There have been many planning studies that show that proton radiation can achieve a more highly conformal dose distribution and appear to spare 50% or more normal tissue from unnecessary irradiation. However, there have been only a handful of retrospective studies that report disease control and side effects of treatment. While the technology looked promising, the definitive clinical data has been lacking to date. Because of this lack of clinical outcome data, the role and benefit of proton radiotherapy has been a subject of great debate in the oncology community. Critics assert that proton radiotherapy is expensive and unproven and therefore a leading culprit in escalating costs of oncologic health care. Proponents assert that when used in the appropriate patient setting, the margin of benefit in terms of improved health outcomes, outweighs the increased cost of treatment.
We embarked on this study to answer help answer the call for prospectively collected clinical outcome data to better define the most appropriate role for proton radiotherapy. Importantly, this study addresses both disease control and side effects of treatment in a pediatric medulloblastoma cohort of children.
Medical Research: What are the main findings?
Dr. Yock: This study shows that disease control in the pediatric medulloblastoma population is very much the same as that which is achieved by photon based radiotherapy treatments. However, more importantly, late side effects commonly attributed to radiotherapy such as neurocognitive decline over time and hearing loss appear to be improved compared with published photon treated cohorts of pediatric medulloblastoma patients. Additionally, adverse late side effects on the cardiopulmonary, GI, and reproductive systems were essentially eliminated.
Medical Research: What should clinicians and patients take away from your report?
Dr. Yock: Proton radiotherapy is a promising modality for pediatric medulloblastoma and appears to dramatically decrease late side effects of treatment. When feasible and available, it should be considered an attractive alternative to photon radiotherapy.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Yock: As far as research funding allows, we plan to continue to follow this cohort of patients to allow further maturation of the data as parents want to know what will become of their child more than seven years into the future. Additionally, we will incorporate other medulloblastoma patients as well enrolled on a joint MGH/MDACC protocol funded by the NCI. We are conducting a similar ongoing study in patients with other curable brain tumors, and tumors outside of the central nervous system such as, rhabdomyosarcoma, other pediatric sarcomas, and neuroblastoma. We have and will continue to describe patient (and parent) reported quality of life metrics.
We recognize that working together with other pediatric oncology centers of excellence will help expedite research and have therefore founded the Pediatric Proton Consortium Registry (PPCR) which opened to enrollment in 2012 and now over 1000 patients have been enrolled. This is a multicenter pediatric radiation oncology registry using the REDCap platform and funded by the NCI/MGH federal share funds. Multiple centers are participating and we will be opening to both proton and photons centers in 2016 to aid and expedite comparative research and to better define the roles of each in the pediatric population requiring radiotherapy.
Medical Research: Is there anything else you would like to add?
Dr. Yock: For more information on ongoing research in pediatric radiation oncology, or if you would like to support our research please see our web site: www.protonsforkids.org and www.pedsprotonregistry.org.
The Lancet Oncology , Volume 0 , Issue 0 ,
Published Online: 29 January 2016
Dr. Torunn Yock, MD (2016). Proton Radiation Therapy: Treats Pediatric Brain Tumor With Fewer Long Term Side Effects