A comprehensive review by University of North Carolina researchers and colleagues highlights the optimal ways that focused, high-dose radiation can be delivered to various types of tumors while sparing normal tissue and mitigating long-term side effects.
The review was reported as a special issue in the International Journal of Radiation Oncology, Biology, Physics.
This analysis was based on an exhaustive review of data and the literature published largely in the past decade. It updates an earlier review that primarily focused on the effects of conventional radiation therapy on normal tissue.
This new review also includes important analyses of how well high-dose radiation can destroy small tumors, such as small brain lesions, lung lesions, and cancers that metastasize to other parts of the body.
“We undertook this review because we have an ever-increasing knowledge about the dose and volume of tissue to which we can direct radiation to both eradicate tumors while also safeguarding the surrounding normal tissue,” Lawrence B. Marks, chair of the UNC Department of Radiation Oncology and Sidney K. Simon Distinguished Professor of Oncology Research at UNC Lineberger Comprehensive Cancer Center, said in a statement. “Today, we are better able to tailor radiotherapy to optimize benefit and minimize risk.”
Conventional radiotherapy, developed nearly a century ago, often broadly hits the tumor and some healthy tissue surrounding the tumor, and is administered in low daily doses, usually over many weeks.
For some patients, their cancer can be treated with more advanced techniques, called stereotactic body radiation therapy, or radiosurgery, that target smaller areas of tissue that are primarily cancerous, treating them at a high dose per day and usually administered for one to five days. These radiosurgery treatments are the focus of this recently published report.
“New computational methods and machines allow us to deliver radiotherapy much more accurately today, allowing us to limit the area where the radiation is targeted, thereby giving us the ability to increase the dose per day,” Marks said. “However, at this point in time we can only use this approach for smallish-sized tumors, but newer techniques may allow us to extend this approach to larger tumors as well.”
The next review will be done when there are discernable shifts or changes in treatment practice patterns, the authors said. However, there is a large review due out next year, in which Marks is participating, that is focusing on use of radiotherapy in pediatric cancers. Radiotherapy is often used sparingly in children due to later-in-life side effects, therefore making it important to know when best to use these treatments.
