Stereotactic Radiotherapy: Potential Therapeutic Gain
Stereotactic radiotherapy, describes a more localized form of radiation that is delivered over a very short course of 1-5 treatments, using large doses per treatment (hypofractionated treatment). With stereotactic radiation approaches, it is possible to deliver a more sharply marginated form of radiation that is more sparing of surrounding tissue, allowing an increased dose to be delivered. This form of applied radiation is biologically ablative of tissue within the high dose volume, and represents a potentially more effective method of eradicating liver and bile duct/gallbladder cancers, compared with prior radiotherapy techniques (21-23).
In an ongoing Multi-Institutional stereotactic radiotherapy dose escalation protocol, liver tolerance to radiation with stereotactic radiotherapy still has not been reached, as long as 30% of the liver tissue is spared from a significant radiation dose. The radiation dose delivered in this study has been estimated as the biological equivalent of two to three times the conventional dose, representing a far more biologically potent radiotherapy application compared with prior “conventional” or standard conformal radiotherapy approaches (22,23). Such a high dose radiotherapy course is only safely delivered by very sophisticated approaches, such as stereotactic radiotherapy or stereotactic radiosurgery.
|
