What is the role of tomotherapy and hypofractionated radiotherapy in the treatment of prostate cancer?

Updated: Nov 29, 2018
  • Author: Isamettin Andrew Aral, MD, MS; Chief Editor: Edward David Kim, MD, FACS  more...
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Answer

The radiotherapeutic approach to carcinoma has been relatively consistent for more than 3 decades. Although refinements in existing treatment technique have allowed higher doses of radiation treatment to be offered to patients with limited disease, there are 2 unique forms of external beam radiotherapy (EBRT) that have garnered increasing interest over the past few years.

The first of these is helical radiotherapy using a computed tomography (CT)-like gantry and a rotating radiation beam that passes through the target area of interest. This modality, termed tomotherapy, has been used in the management of primary central nervous system (CNS) tumors and viscera-based malignancies. Although the CT-like gantry generates megavoltage radiation, its design allows ready acquisition of CT-like images, which have been successfully used in optimizing patient positioning on a daily basis. [27]

The second distinct modality is hypofractionated radiotherapy. In this form of therapy, radiation is delivered from an accelerator; however, the equipment is mounted to a computer-guided robotic arm. Because the machine is capable of treating the target at angles that are not possible with conventional rotation-based equipment, it yields the theoretical advantage of conforming the dose more closely to the target organ’s shape.

Unlike conventional forms of radiotherapy, this treatment process is administered over the course of approximately 1 week. This duration is substantially shorter than that of conventional intensity-modulated radiotherapy (IMRT) or image-guided radiotherapy (IGRT), which entails daily (Monday through Friday) treatment for 6-8 weeks.

The Accuray CyberKnife is used in several clinical centers throughout the United States. Early clinical data suggest that the hypofractionated regimens may allow adequate dose delivery while causing similar (and, potentially, reduced) toxicity to normal tissue. [28]

Accelerated hypofractionated radiotherapy may offer great promise in the management of prostate carcinoma. To date, however, the clinical use of this form of therapy has been insufficient to support its routine use in all patients.


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