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Current Status and Future Potential of Advanced Technologies in Radiation Oncology

Current Status and Future Potential of Advanced Technologies in Radiation Oncology

ABSTRACT:   This article is part of a CME activity described in Oncology Vol. 23 No. 3  

The entry of new technology into medical practice is complex. New technology in radiation oncology includes advances in imaging (including anatomic and molecular/functional imaging) and radiation therapy planning and delivery involving intensity-modulated radiation therapy (IMRT), stereotactic radiation therapy (SRT), and therapy with particles such as protons and carbon ions. The necessary research and development includes establishing baselines as to the current state of the art, and establishing quality assurance guidelines and procedures that meet the demands of the new technology. It further involves developing consensus as to what data and studies are needed, ranging from single-institution studies to multi-institutional phase II and phase III clinical trials, including measures of cost-effectiveness as appropriate.

On November 30–December 2, 2006, the Radiation Research Program of the Division of Cancer Treatment and Diagnosis of the National Cancer Institute (NCI) hosted a workshop entitled “Advanced Technologies in Radiation Oncology: Evaluating the Current Status and Future Potential of Proton and Other Heavy Charged- Particle Radiation Therapy, Intensity Modulated Radiation Therapy and Stereotactic Radiation Therapy.” The purpose of this workshop was to discuss current issues related to the advanced technologies, with an eye toward (1) defining the specific toxicities that have limited the success of “conventional” radiation therapy, (2) examining the evidence from phase III studies for improvements attributed to the advanced technologies in the management of several cancers commonly treated with radiation therapy, and (3) determining the opportunities and priorities for further technologic development and clinical trials.

The 2½-day workshop included presentations on general topics such as quality assurance, a framework for device-based clinical trials, and device evaluation from the perspective of the US Food and Drug Administration (FDA). In addition, there were several presentations on the state of the science by anatomic site, followed by three breakout groups: (1) brain, head and neck, pediatrics; (2) trunk (breast, lung, upper abdomen); and (3) pelvis (prostate, uterus, colon/rectum).

The workshop agenda, a list of the workshop participants, and their presentations can be found at the following website (more details may be obtained from the authors): http:// www3.cancer.gov/rrp/workshop/ 2006AdvancedRadiationTech/presentations. html. The participants had been selected by National Institutes of Health (NIH) staff to represent a broad spectrum of expertise from NIH-funded grantees, cooperative cancer clinical trials groups, cancer centers, professional societies, and industry. Each participant declared their conflicts of interest to all the participants at the outset of the workshop. No formal votes were taken, but the leaders of the breakout sessions did summarize the deliberations for NIH staff, who were solely responsible for compiling this report.

General Summary
The new technologies undoubtedly offer a substantial theoretical advantage in radiation dose distributions that, if realized in clinical practice, may help many cancer patients live longer and/or better. The precision of the advanced technologies may allow us to reduce the volume of normal tissue irradiated in the vicinity of the clinical target volume (CTV) or, in other words, decrease the planning target volume so that it approximates the CTV. Therefore, defining the precise size and shape of the CTV as well as the organs at risk becomes critical, as does accounting for changes in the position (motion) and changes in size and shape (deformation) of the CTV and the organs at risk, between and within radiation fractions, in order to avoid inadvertently missing the CTV.

The advanced technologies can also result in a greater volume of healthy tissue receiving some radiation compared with “conventional” techniques of radiation therapy, due to the generation of such radiation by the machines and/or the multiple fields employed.[1,2] Therefore, investigators must also consider long-term toxicity, including the risk of new radiation-induced cancers.

The costs of the new technologies were considered in the discussions in general terms only, including the need for expert personnel, additional time for treatment planning and delivery, and the cost of equipment. Issues of reimbursement and the regulation of how and when new treatments and technologies are approved for clinical use, however, were considered to be beyond the scope of this workshop and the mission of the NCI.

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